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bazarr/libs/sqlalchemy/sql/elements.py

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Replaced peewee with sqlalchemy as ORM. This is a major change, please report related issues on Discord.
1 year ago
# sql/elements.py
# Copyright (C) 2005-2023 the SQLAlchemy authors and contributors
# <see AUTHORS file>
#
# This module is part of SQLAlchemy and is released under
# the MIT License: https://www.opensource.org/licenses/mit-license.php
# mypy: allow-untyped-defs, allow-untyped-calls
"""Core SQL expression elements, including :class:`_expression.ClauseElement`,
:class:`_expression.ColumnElement`, and derived classes.
"""
from __future__ import annotations
from decimal import Decimal
from enum import IntEnum
import itertools
import operator
import re
import typing
from typing import AbstractSet
from typing import Any
from typing import Callable
from typing import cast
from typing import Dict
from typing import FrozenSet
from typing import Generic
from typing import Iterable
from typing import Iterator
from typing import List
from typing import Mapping
from typing import Optional
from typing import overload
from typing import Sequence
from typing import Set
from typing import Tuple as typing_Tuple
from typing import Type
from typing import TYPE_CHECKING
from typing import TypeVar
from typing import Union
from . import coercions
from . import operators
from . import roles
from . import traversals
from . import type_api
from ._typing import has_schema_attr
from ._typing import is_named_from_clause
from ._typing import is_quoted_name
from ._typing import is_tuple_type
from .annotation import Annotated
from .annotation import SupportsWrappingAnnotations
from .base import _clone
from .base import _expand_cloned
from .base import _generative
from .base import _NoArg
from .base import Executable
from .base import Generative
from .base import HasMemoized
from .base import Immutable
from .base import NO_ARG
from .base import SingletonConstant
from .cache_key import MemoizedHasCacheKey
from .cache_key import NO_CACHE
from .coercions import _document_text_coercion # noqa
from .operators import ColumnOperators
from .traversals import HasCopyInternals
from .visitors import cloned_traverse
from .visitors import ExternallyTraversible
from .visitors import InternalTraversal
from .visitors import traverse
from .visitors import Visitable
from .. import exc
from .. import inspection
from .. import util
from ..util import HasMemoized_ro_memoized_attribute
from ..util import TypingOnly
from ..util.typing import Literal
from ..util.typing import Self
if typing.TYPE_CHECKING:
from ._typing import _ColumnExpressionArgument
from ._typing import _ColumnExpressionOrStrLabelArgument
from ._typing import _InfoType
from ._typing import _PropagateAttrsType
from ._typing import _TypeEngineArgument
from .cache_key import _CacheKeyTraversalType
from .cache_key import CacheKey
from .compiler import Compiled
from .compiler import SQLCompiler
from .functions import FunctionElement
from .operators import OperatorType
from .schema import _ServerDefaultType
from .schema import Column
from .schema import DefaultGenerator
from .schema import FetchedValue
from .schema import ForeignKey
from .selectable import _SelectIterable
from .selectable import FromClause
from .selectable import NamedFromClause
from .selectable import TextualSelect
from .sqltypes import TupleType
from .type_api import TypeEngine
from .visitors import _CloneCallableType
from .visitors import _TraverseInternalsType
from ..engine import Connection
from ..engine import Dialect
from ..engine import Engine
from ..engine.interfaces import _CoreMultiExecuteParams
from ..engine.interfaces import CacheStats
from ..engine.interfaces import CompiledCacheType
from ..engine.interfaces import CoreExecuteOptionsParameter
from ..engine.interfaces import SchemaTranslateMapType
from ..engine.result import Result
_NUMERIC = Union[float, Decimal]
_NUMBER = Union[float, int, Decimal]
_T = TypeVar("_T", bound="Any")
_OPT = TypeVar("_OPT", bound="Any")
_NT = TypeVar("_NT", bound="_NUMERIC")
_NMT = TypeVar("_NMT", bound="_NUMBER")
def literal(
value: Any,
type_: Optional[_TypeEngineArgument[_T]] = None,
literal_execute: bool = False,
) -> BindParameter[_T]:
r"""Return a literal clause, bound to a bind parameter.
Literal clauses are created automatically when non-
:class:`_expression.ClauseElement` objects (such as strings, ints, dates,
etc.) are
used in a comparison operation with a :class:`_expression.ColumnElement`
subclass,
such as a :class:`~sqlalchemy.schema.Column` object. Use this function
to force the generation of a literal clause, which will be created as a
:class:`BindParameter` with a bound value.
:param value: the value to be bound. Can be any Python object supported by
the underlying DB-API, or is translatable via the given type argument.
:param type\_: an optional :class:`~sqlalchemy.types.TypeEngine` which will
provide bind-parameter translation for this literal.
:param literal_execute: optional bool, when True, the SQL engine will
attempt to render the bound value directly in the SQL statement at
execution time rather than providing as a parameter value.
.. versionadded:: 2.0
"""
return coercions.expect(
roles.LiteralValueRole,
value,
type_=type_,
literal_execute=literal_execute,
)
def literal_column(
text: str, type_: Optional[_TypeEngineArgument[_T]] = None
) -> ColumnClause[_T]:
r"""Produce a :class:`.ColumnClause` object that has the
:paramref:`_expression.column.is_literal` flag set to True.
:func:`_expression.literal_column` is similar to
:func:`_expression.column`, except that
it is more often used as a "standalone" column expression that renders
exactly as stated; while :func:`_expression.column`
stores a string name that
will be assumed to be part of a table and may be quoted as such,
:func:`_expression.literal_column` can be that,
or any other arbitrary column-oriented
expression.
:param text: the text of the expression; can be any SQL expression.
Quoting rules will not be applied. To specify a column-name expression
which should be subject to quoting rules, use the :func:`column`
function.
:param type\_: an optional :class:`~sqlalchemy.types.TypeEngine`
object which will
provide result-set translation and additional expression semantics for
this column. If left as ``None`` the type will be :class:`.NullType`.
.. seealso::
:func:`_expression.column`
:func:`_expression.text`
:ref:`tutorial_select_arbitrary_text`
"""
return ColumnClause(text, type_=type_, is_literal=True)
class CompilerElement(Visitable):
"""base class for SQL elements that can be compiled to produce a
SQL string.
.. versionadded:: 2.0
"""
__slots__ = ()
__visit_name__ = "compiler_element"
supports_execution = False
stringify_dialect = "default"
@util.preload_module("sqlalchemy.engine.default")
@util.preload_module("sqlalchemy.engine.url")
def compile(
self,
bind: Optional[Union[Engine, Connection]] = None,
dialect: Optional[Dialect] = None,
**kw: Any,
) -> Compiled:
"""Compile this SQL expression.
The return value is a :class:`~.Compiled` object.
Calling ``str()`` or ``unicode()`` on the returned value will yield a
string representation of the result. The
:class:`~.Compiled` object also can return a
dictionary of bind parameter names and values
using the ``params`` accessor.
:param bind: An :class:`.Connection` or :class:`.Engine` which
can provide a :class:`.Dialect` in order to generate a
:class:`.Compiled` object. If the ``bind`` and
``dialect`` parameters are both omitted, a default SQL compiler
is used.
:param column_keys: Used for INSERT and UPDATE statements, a list of
column names which should be present in the VALUES clause of the
compiled statement. If ``None``, all columns from the target table
object are rendered.
:param dialect: A :class:`.Dialect` instance which can generate
a :class:`.Compiled` object. This argument takes precedence over
the ``bind`` argument.
:param compile_kwargs: optional dictionary of additional parameters
that will be passed through to the compiler within all "visit"
methods. This allows any custom flag to be passed through to
a custom compilation construct, for example. It is also used
for the case of passing the ``literal_binds`` flag through::
from sqlalchemy.sql import table, column, select
t = table('t', column('x'))
s = select(t).where(t.c.x == 5)
print(s.compile(compile_kwargs={"literal_binds": True}))
.. versionadded:: 0.9.0
.. seealso::
:ref:`faq_sql_expression_string`
"""
if dialect is None:
if bind:
dialect = bind.dialect
elif self.stringify_dialect == "default":
default = util.preloaded.engine_default
dialect = default.StrCompileDialect()
else:
url = util.preloaded.engine_url
dialect = url.URL.create(
self.stringify_dialect
).get_dialect()()
return self._compiler(dialect, **kw)
def _compiler(self, dialect: Dialect, **kw: Any) -> Compiled:
"""Return a compiler appropriate for this ClauseElement, given a
Dialect."""
if TYPE_CHECKING:
assert isinstance(self, ClauseElement)
return dialect.statement_compiler(dialect, self, **kw)
def __str__(self) -> str:
return str(self.compile())
@inspection._self_inspects
class ClauseElement(
SupportsWrappingAnnotations,
MemoizedHasCacheKey,
HasCopyInternals,
ExternallyTraversible,
CompilerElement,
):
"""Base class for elements of a programmatically constructed SQL
expression.
"""
__visit_name__ = "clause"
if TYPE_CHECKING:
@util.memoized_property
def _propagate_attrs(self) -> _PropagateAttrsType:
"""like annotations, however these propagate outwards liberally
as SQL constructs are built, and are set up at construction time.
"""
...
else:
_propagate_attrs = util.EMPTY_DICT
@util.ro_memoized_property
def description(self) -> Optional[str]:
return None
_is_clone_of: Optional[ClauseElement] = None
is_clause_element = True
is_selectable = False
is_dml = False
_is_column_element = False
_is_keyed_column_element = False
_is_table = False
_gen_static_annotations_cache_key = False
_is_textual = False
_is_from_clause = False
_is_returns_rows = False
_is_text_clause = False
_is_from_container = False
_is_select_container = False
_is_select_base = False
_is_select_statement = False
_is_bind_parameter = False
_is_clause_list = False
_is_lambda_element = False
_is_singleton_constant = False
_is_immutable = False
_is_star = False
@property
def _order_by_label_element(self) -> Optional[Label[Any]]:
return None
_cache_key_traversal: _CacheKeyTraversalType = None
negation_clause: ColumnElement[bool]
if typing.TYPE_CHECKING:
def get_children(
self, *, omit_attrs: typing_Tuple[str, ...] = ..., **kw: Any
) -> Iterable[ClauseElement]:
...
@util.ro_non_memoized_property
def _from_objects(self) -> List[FromClause]:
return []
def _set_propagate_attrs(self, values: Mapping[str, Any]) -> Self:
# usually, self._propagate_attrs is empty here. one case where it's
# not is a subquery against ORM select, that is then pulled as a
# property of an aliased class. should all be good
# assert not self._propagate_attrs
self._propagate_attrs = util.immutabledict(values)
return self
def _clone(self, **kw: Any) -> Self:
"""Create a shallow copy of this ClauseElement.
This method may be used by a generative API. Its also used as
part of the "deep" copy afforded by a traversal that combines
the _copy_internals() method.
"""
skip = self._memoized_keys
c = self.__class__.__new__(self.__class__)
if skip:
# ensure this iteration remains atomic
c.__dict__ = {
k: v for k, v in self.__dict__.copy().items() if k not in skip
}
else:
c.__dict__ = self.__dict__.copy()
# this is a marker that helps to "equate" clauses to each other
# when a Select returns its list of FROM clauses. the cloning
# process leaves around a lot of remnants of the previous clause
# typically in the form of column expressions still attached to the
# old table.
cc = self._is_clone_of
c._is_clone_of = cc if cc is not None else self
return c
def _negate_in_binary(self, negated_op, original_op):
"""a hook to allow the right side of a binary expression to respond
to a negation of the binary expression.
Used for the special case of expanding bind parameter with IN.
"""
return self
def _with_binary_element_type(self, type_):
"""in the context of binary expression, convert the type of this
object to the one given.
applies only to :class:`_expression.ColumnElement` classes.
"""
return self
@property
def _constructor(self):
"""return the 'constructor' for this ClauseElement.
This is for the purposes for creating a new object of
this type. Usually, its just the element's __class__.
However, the "Annotated" version of the object overrides
to return the class of its proxied element.
"""
return self.__class__
@HasMemoized.memoized_attribute
def _cloned_set(self):
"""Return the set consisting all cloned ancestors of this
ClauseElement.
Includes this ClauseElement. This accessor tends to be used for
FromClause objects to identify 'equivalent' FROM clauses, regardless
of transformative operations.
"""
s = util.column_set()
f: Optional[ClauseElement] = self
# note this creates a cycle, asserted in test_memusage. however,
# turning this into a plain @property adds tends of thousands of method
# calls to Core / ORM performance tests, so the small overhead
# introduced by the relatively small amount of short term cycles
# produced here is preferable
while f is not None:
s.add(f)
f = f._is_clone_of
return s
@property
def entity_namespace(self):
raise AttributeError(
"This SQL expression has no entity namespace "
"with which to filter from."
)
def __getstate__(self):
d = self.__dict__.copy()
d.pop("_is_clone_of", None)
d.pop("_generate_cache_key", None)
return d
def _execute_on_connection(
self,
connection: Connection,
distilled_params: _CoreMultiExecuteParams,
execution_options: CoreExecuteOptionsParameter,
) -> Result[Any]:
if self.supports_execution:
if TYPE_CHECKING:
assert isinstance(self, Executable)
return connection._execute_clauseelement(
self, distilled_params, execution_options
)
else:
raise exc.ObjectNotExecutableError(self)
def _execute_on_scalar(
self,
connection: Connection,
distilled_params: _CoreMultiExecuteParams,
execution_options: CoreExecuteOptionsParameter,
) -> Any:
"""an additional hook for subclasses to provide a different
implementation for connection.scalar() vs. connection.execute().
.. versionadded:: 2.0
"""
return self._execute_on_connection(
connection, distilled_params, execution_options
).scalar()
def unique_params(
self,
__optionaldict: Optional[Dict[str, Any]] = None,
**kwargs: Any,
) -> Self:
"""Return a copy with :func:`_expression.bindparam` elements
replaced.
Same functionality as :meth:`_expression.ClauseElement.params`,
except adds `unique=True`
to affected bind parameters so that multiple statements can be
used.
"""
return self._replace_params(True, __optionaldict, kwargs)
def params(
self,
__optionaldict: Optional[Mapping[str, Any]] = None,
**kwargs: Any,
) -> Self:
"""Return a copy with :func:`_expression.bindparam` elements
replaced.
Returns a copy of this ClauseElement with
:func:`_expression.bindparam`
elements replaced with values taken from the given dictionary::
>>> clause = column('x') + bindparam('foo')
>>> print(clause.compile().params)
{'foo':None}
>>> print(clause.params({'foo':7}).compile().params)
{'foo':7}
"""
return self._replace_params(False, __optionaldict, kwargs)
def _replace_params(
self,
unique: bool,
optionaldict: Optional[Mapping[str, Any]],
kwargs: Dict[str, Any],
) -> Self:
if optionaldict:
kwargs.update(optionaldict)
def visit_bindparam(bind: BindParameter[Any]) -> None:
if bind.key in kwargs:
bind.value = kwargs[bind.key]
bind.required = False
if unique:
bind._convert_to_unique()
return cloned_traverse(
self,
{"maintain_key": True, "detect_subquery_cols": True},
{"bindparam": visit_bindparam},
)
def compare(self, other: ClauseElement, **kw: Any) -> bool:
r"""Compare this :class:`_expression.ClauseElement` to
the given :class:`_expression.ClauseElement`.
Subclasses should override the default behavior, which is a
straight identity comparison.
\**kw are arguments consumed by subclass ``compare()`` methods and
may be used to modify the criteria for comparison
(see :class:`_expression.ColumnElement`).
"""
return traversals.compare(self, other, **kw)
def self_group(
self, against: Optional[OperatorType] = None
) -> ClauseElement:
"""Apply a 'grouping' to this :class:`_expression.ClauseElement`.
This method is overridden by subclasses to return a "grouping"
construct, i.e. parenthesis. In particular it's used by "binary"
expressions to provide a grouping around themselves when placed into a
larger expression, as well as by :func:`_expression.select`
constructs when placed into the FROM clause of another
:func:`_expression.select`. (Note that subqueries should be
normally created using the :meth:`_expression.Select.alias` method,
as many
platforms require nested SELECT statements to be named).
As expressions are composed together, the application of
:meth:`self_group` is automatic - end-user code should never
need to use this method directly. Note that SQLAlchemy's
clause constructs take operator precedence into account -
so parenthesis might not be needed, for example, in
an expression like ``x OR (y AND z)`` - AND takes precedence
over OR.
The base :meth:`self_group` method of
:class:`_expression.ClauseElement`
just returns self.
"""
return self
def _ungroup(self) -> ClauseElement:
"""Return this :class:`_expression.ClauseElement`
without any groupings.
"""
return self
def _compile_w_cache(
self,
dialect: Dialect,
*,
compiled_cache: Optional[CompiledCacheType],
column_keys: List[str],
for_executemany: bool = False,
schema_translate_map: Optional[SchemaTranslateMapType] = None,
**kw: Any,
) -> typing_Tuple[
Compiled, Optional[Sequence[BindParameter[Any]]], CacheStats
]:
elem_cache_key: Optional[CacheKey]
if compiled_cache is not None and dialect._supports_statement_cache:
elem_cache_key = self._generate_cache_key()
else:
elem_cache_key = None
if elem_cache_key is not None:
if TYPE_CHECKING:
assert compiled_cache is not None
cache_key, extracted_params = elem_cache_key
key = (
dialect,
cache_key,
tuple(column_keys),
bool(schema_translate_map),
for_executemany,
)
compiled_sql = compiled_cache.get(key)
if compiled_sql is None:
cache_hit = dialect.CACHE_MISS
compiled_sql = self._compiler(
dialect,
cache_key=elem_cache_key,
column_keys=column_keys,
for_executemany=for_executemany,
schema_translate_map=schema_translate_map,
**kw,
)
compiled_cache[key] = compiled_sql
else:
cache_hit = dialect.CACHE_HIT
else:
extracted_params = None
compiled_sql = self._compiler(
dialect,
cache_key=elem_cache_key,
column_keys=column_keys,
for_executemany=for_executemany,
schema_translate_map=schema_translate_map,
**kw,
)
if not dialect._supports_statement_cache:
cache_hit = dialect.NO_DIALECT_SUPPORT
elif compiled_cache is None:
cache_hit = dialect.CACHING_DISABLED
else:
cache_hit = dialect.NO_CACHE_KEY
return compiled_sql, extracted_params, cache_hit
def __invert__(self):
# undocumented element currently used by the ORM for
# relationship.contains()
if hasattr(self, "negation_clause"):
return self.negation_clause
else:
return self._negate()
def _negate(self) -> ClauseElement:
grouped = self.self_group(against=operators.inv)
assert isinstance(grouped, ColumnElement)
return UnaryExpression(grouped, operator=operators.inv)
def __bool__(self):
raise TypeError("Boolean value of this clause is not defined")
def __repr__(self):
friendly = self.description
if friendly is None:
return object.__repr__(self)
else:
return "<%s.%s at 0x%x; %s>" % (
self.__module__,
self.__class__.__name__,
id(self),
friendly,
)
class DQLDMLClauseElement(ClauseElement):
"""represents a :class:`.ClauseElement` that compiles to a DQL or DML
expression, not DDL.
.. versionadded:: 2.0
"""
if typing.TYPE_CHECKING:
def _compiler(self, dialect: Dialect, **kw: Any) -> SQLCompiler:
"""Return a compiler appropriate for this ClauseElement, given a
Dialect."""
...
def compile( # noqa: A001
self,
bind: Optional[Union[Engine, Connection]] = None,
dialect: Optional[Dialect] = None,
**kw: Any,
) -> SQLCompiler:
...
class CompilerColumnElement(
roles.DMLColumnRole,
roles.DDLConstraintColumnRole,
roles.ColumnsClauseRole,
CompilerElement,
):
"""A compiler-only column element used for ad-hoc string compilations.
.. versionadded:: 2.0
"""
__slots__ = ()
_propagate_attrs = util.EMPTY_DICT
# SQLCoreOperations should be suiting the ExpressionElementRole
# and ColumnsClauseRole. however the MRO issues become too elaborate
# at the moment.
class SQLCoreOperations(Generic[_T], ColumnOperators, TypingOnly):
__slots__ = ()
# annotations for comparison methods
# these are from operators->Operators / ColumnOperators,
# redefined with the specific types returned by ColumnElement hierarchies
if typing.TYPE_CHECKING:
@util.non_memoized_property
def _propagate_attrs(self) -> _PropagateAttrsType:
...
def operate(
self, op: OperatorType, *other: Any, **kwargs: Any
) -> ColumnElement[Any]:
...
def reverse_operate(
self, op: OperatorType, other: Any, **kwargs: Any
) -> ColumnElement[Any]:
...
def op(
self,
opstring: str,
precedence: int = 0,
is_comparison: bool = False,
return_type: Optional[_TypeEngineArgument[_OPT]] = None,
python_impl: Optional[Callable[..., Any]] = None,
) -> Callable[[Any], BinaryExpression[_OPT]]:
...
def bool_op(
self,
opstring: str,
precedence: int = 0,
python_impl: Optional[Callable[..., Any]] = None,
) -> Callable[[Any], BinaryExpression[bool]]:
...
def __and__(self, other: Any) -> BooleanClauseList:
...
def __or__(self, other: Any) -> BooleanClauseList:
...
def __invert__(self) -> ColumnElement[_T]:
...
def __lt__(self, other: Any) -> ColumnElement[bool]:
...
def __le__(self, other: Any) -> ColumnElement[bool]:
...
def __eq__(self, other: Any) -> ColumnElement[bool]: # type: ignore[override] # noqa: E501
...
def __ne__(self, other: Any) -> ColumnElement[bool]: # type: ignore[override] # noqa: E501
...
def is_distinct_from(self, other: Any) -> ColumnElement[bool]:
...
def is_not_distinct_from(self, other: Any) -> ColumnElement[bool]:
...
def __gt__(self, other: Any) -> ColumnElement[bool]:
...
def __ge__(self, other: Any) -> ColumnElement[bool]:
...
def __neg__(self) -> UnaryExpression[_T]:
...
def __contains__(self, other: Any) -> ColumnElement[bool]:
...
def __getitem__(self, index: Any) -> ColumnElement[Any]:
...
@overload
def concat(self: _SQO[str], other: Any) -> ColumnElement[str]:
...
@overload
def concat(self, other: Any) -> ColumnElement[Any]:
...
def concat(self, other: Any) -> ColumnElement[Any]:
...
def like(
self, other: Any, escape: Optional[str] = None
) -> BinaryExpression[bool]:
...
def ilike(
self, other: Any, escape: Optional[str] = None
) -> BinaryExpression[bool]:
...
def in_(
self,
other: Union[
Iterable[Any], BindParameter[Any], roles.InElementRole
],
) -> BinaryExpression[bool]:
...
def not_in(
self,
other: Union[
Iterable[Any], BindParameter[Any], roles.InElementRole
],
) -> BinaryExpression[bool]:
...
def notin_(
self,
other: Union[
Iterable[Any], BindParameter[Any], roles.InElementRole
],
) -> BinaryExpression[bool]:
...
def not_like(
self, other: Any, escape: Optional[str] = None
) -> BinaryExpression[bool]:
...
def notlike(
self, other: Any, escape: Optional[str] = None
) -> BinaryExpression[bool]:
...
def not_ilike(
self, other: Any, escape: Optional[str] = None
) -> BinaryExpression[bool]:
...
def notilike(
self, other: Any, escape: Optional[str] = None
) -> BinaryExpression[bool]:
...
def is_(self, other: Any) -> BinaryExpression[bool]:
...
def is_not(self, other: Any) -> BinaryExpression[bool]:
...
def isnot(self, other: Any) -> BinaryExpression[bool]:
...
def startswith(
self,
other: Any,
escape: Optional[str] = None,
autoescape: bool = False,
) -> ColumnElement[bool]:
...
def endswith(
self,
other: Any,
escape: Optional[str] = None,
autoescape: bool = False,
) -> ColumnElement[bool]:
...
def contains(self, other: Any, **kw: Any) -> ColumnElement[bool]:
...
def match(self, other: Any, **kwargs: Any) -> ColumnElement[bool]:
...
def regexp_match(
self, pattern: Any, flags: Optional[str] = None
) -> ColumnElement[bool]:
...
def regexp_replace(
self, pattern: Any, replacement: Any, flags: Optional[str] = None
) -> ColumnElement[str]:
...
def desc(self) -> UnaryExpression[_T]:
...
def asc(self) -> UnaryExpression[_T]:
...
def nulls_first(self) -> UnaryExpression[_T]:
...
def nullsfirst(self) -> UnaryExpression[_T]:
...
def nulls_last(self) -> UnaryExpression[_T]:
...
def nullslast(self) -> UnaryExpression[_T]:
...
def collate(self, collation: str) -> CollationClause:
...
def between(
self, cleft: Any, cright: Any, symmetric: bool = False
) -> BinaryExpression[bool]:
...
def distinct(self: _SQO[_T]) -> UnaryExpression[_T]:
...
def any_(self) -> CollectionAggregate[Any]:
...
def all_(self) -> CollectionAggregate[Any]:
...
# numeric overloads. These need more tweaking
# in particular they all need to have a variant for Optiona[_T]
# because Optional only applies to the data side, not the expression
# side
@overload
def __add__(
self: _SQO[_NMT],
other: Any,
) -> ColumnElement[_NMT]:
...
@overload
def __add__(
self: _SQO[str],
other: Any,
) -> ColumnElement[str]:
...
def __add__(self, other: Any) -> ColumnElement[Any]:
...
@overload
def __radd__(self: _SQO[_NT], other: Any) -> ColumnElement[_NT]:
...
@overload
def __radd__(self: _SQO[int], other: Any) -> ColumnElement[int]:
...
@overload
def __radd__(self: _SQO[str], other: Any) -> ColumnElement[str]:
...
def __radd__(self, other: Any) -> ColumnElement[Any]:
...
@overload
def __sub__(
self: _SQO[_NMT],
other: Any,
) -> ColumnElement[_NMT]:
...
@overload
def __sub__(self, other: Any) -> ColumnElement[Any]:
...
def __sub__(self, other: Any) -> ColumnElement[Any]:
...
@overload
def __rsub__(
self: _SQO[_NMT],
other: Any,
) -> ColumnElement[_NMT]:
...
@overload
def __rsub__(self, other: Any) -> ColumnElement[Any]:
...
def __rsub__(self, other: Any) -> ColumnElement[Any]:
...
@overload
def __mul__(
self: _SQO[_NMT],
other: Any,
) -> ColumnElement[_NMT]:
...
@overload
def __mul__(self, other: Any) -> ColumnElement[Any]:
...
def __mul__(self, other: Any) -> ColumnElement[Any]:
...
@overload
def __rmul__(
self: _SQO[_NMT],
other: Any,
) -> ColumnElement[_NMT]:
...
@overload
def __rmul__(self, other: Any) -> ColumnElement[Any]:
...
def __rmul__(self, other: Any) -> ColumnElement[Any]:
...
@overload
def __mod__(self: _SQO[_NMT], other: Any) -> ColumnElement[_NMT]:
...
@overload
def __mod__(self, other: Any) -> ColumnElement[Any]:
...
def __mod__(self, other: Any) -> ColumnElement[Any]:
...
@overload
def __rmod__(self: _SQO[_NMT], other: Any) -> ColumnElement[_NMT]:
...
@overload
def __rmod__(self, other: Any) -> ColumnElement[Any]:
...
def __rmod__(self, other: Any) -> ColumnElement[Any]:
...
@overload
def __truediv__(
self: _SQO[int], other: Any
) -> ColumnElement[_NUMERIC]:
...
@overload
def __truediv__(self: _SQO[_NT], other: Any) -> ColumnElement[_NT]:
...
@overload
def __truediv__(self, other: Any) -> ColumnElement[Any]:
...
def __truediv__(self, other: Any) -> ColumnElement[Any]:
...
@overload
def __rtruediv__(
self: _SQO[_NMT], other: Any
) -> ColumnElement[_NUMERIC]:
...
@overload
def __rtruediv__(self, other: Any) -> ColumnElement[Any]:
...
def __rtruediv__(self, other: Any) -> ColumnElement[Any]:
...
@overload
def __floordiv__(self: _SQO[_NMT], other: Any) -> ColumnElement[_NMT]:
...
@overload
def __floordiv__(self, other: Any) -> ColumnElement[Any]:
...
def __floordiv__(self, other: Any) -> ColumnElement[Any]:
...
@overload
def __rfloordiv__(self: _SQO[_NMT], other: Any) -> ColumnElement[_NMT]:
...
@overload
def __rfloordiv__(self, other: Any) -> ColumnElement[Any]:
...
def __rfloordiv__(self, other: Any) -> ColumnElement[Any]:
...
class SQLColumnExpression(
SQLCoreOperations[_T], roles.ExpressionElementRole[_T], TypingOnly
):
"""A type that may be used to indicate any SQL column element or object
that acts in place of one.
:class:`.SQLColumnExpression` is a base of
:class:`.ColumnElement`, as well as within the bases of ORM elements
such as :class:`.InstrumentedAttribute`, and may be used in :pep:`484`
typing to indicate arguments or return values that should behave
as column expressions.
.. versionadded:: 2.0.0b4
"""
__slots__ = ()
_SQO = SQLCoreOperations
class ColumnElement(
roles.ColumnArgumentOrKeyRole,
roles.StatementOptionRole,
roles.WhereHavingRole,
roles.BinaryElementRole[_T],
roles.OrderByRole,
roles.ColumnsClauseRole,
roles.LimitOffsetRole,
roles.DMLColumnRole,
roles.DDLConstraintColumnRole,
roles.DDLExpressionRole,
SQLColumnExpression[_T],
DQLDMLClauseElement,
):
"""Represent a column-oriented SQL expression suitable for usage in the
"columns" clause, WHERE clause etc. of a statement.
While the most familiar kind of :class:`_expression.ColumnElement` is the
:class:`_schema.Column` object, :class:`_expression.ColumnElement`
serves as the basis
for any unit that may be present in a SQL expression, including
the expressions themselves, SQL functions, bound parameters,
literal expressions, keywords such as ``NULL``, etc.
:class:`_expression.ColumnElement`
is the ultimate base class for all such elements.
A wide variety of SQLAlchemy Core functions work at the SQL expression
level, and are intended to accept instances of
:class:`_expression.ColumnElement` as
arguments. These functions will typically document that they accept a
"SQL expression" as an argument. What this means in terms of SQLAlchemy
usually refers to an input which is either already in the form of a
:class:`_expression.ColumnElement` object,
or a value which can be **coerced** into
one. The coercion rules followed by most, but not all, SQLAlchemy Core
functions with regards to SQL expressions are as follows:
* a literal Python value, such as a string, integer or floating
point value, boolean, datetime, ``Decimal`` object, or virtually
any other Python object, will be coerced into a "literal bound
value". This generally means that a :func:`.bindparam` will be
produced featuring the given value embedded into the construct; the
resulting :class:`.BindParameter` object is an instance of
:class:`_expression.ColumnElement`.
The Python value will ultimately be sent
to the DBAPI at execution time as a parameterized argument to the
``execute()`` or ``executemany()`` methods, after SQLAlchemy
type-specific converters (e.g. those provided by any associated
:class:`.TypeEngine` objects) are applied to the value.
* any special object value, typically ORM-level constructs, which
feature an accessor called ``__clause_element__()``. The Core
expression system looks for this method when an object of otherwise
unknown type is passed to a function that is looking to coerce the
argument into a :class:`_expression.ColumnElement` and sometimes a
:class:`_expression.SelectBase` expression.
It is used within the ORM to
convert from ORM-specific objects like mapped classes and
mapped attributes into Core expression objects.
* The Python ``None`` value is typically interpreted as ``NULL``,
which in SQLAlchemy Core produces an instance of :func:`.null`.
A :class:`_expression.ColumnElement` provides the ability to generate new
:class:`_expression.ColumnElement`
objects using Python expressions. This means that Python operators
such as ``==``, ``!=`` and ``<`` are overloaded to mimic SQL operations,
and allow the instantiation of further :class:`_expression.ColumnElement`
instances
which are composed from other, more fundamental
:class:`_expression.ColumnElement`
objects. For example, two :class:`.ColumnClause` objects can be added
together with the addition operator ``+`` to produce
a :class:`.BinaryExpression`.
Both :class:`.ColumnClause` and :class:`.BinaryExpression` are subclasses
of :class:`_expression.ColumnElement`:
.. sourcecode:: pycon+sql
>>> from sqlalchemy.sql import column
>>> column('a') + column('b')
<sqlalchemy.sql.expression.BinaryExpression object at 0x101029dd0>
>>> print(column('a') + column('b'))
{printsql}a + b
.. seealso::
:class:`_schema.Column`
:func:`_expression.column`
"""
__visit_name__ = "column_element"
primary_key: bool = False
_is_clone_of: Optional[ColumnElement[_T]]
_is_column_element = True
foreign_keys: AbstractSet[ForeignKey] = frozenset()
@util.memoized_property
def _proxies(self) -> List[ColumnElement[Any]]:
return []
@util.non_memoized_property
def _tq_label(self) -> Optional[str]:
"""The named label that can be used to target
this column in a result set in a "table qualified" context.
This label is almost always the label used when
rendering <expr> AS <label> in a SELECT statement when using
the LABEL_STYLE_TABLENAME_PLUS_COL label style, which is what the
legacy ORM ``Query`` object uses as well.
For a regular Column bound to a Table, this is typically the label
<tablename>_<columnname>. For other constructs, different rules
may apply, such as anonymized labels and others.
.. versionchanged:: 1.4.21 renamed from ``._label``
"""
return None
key: Optional[str] = None
"""The 'key' that in some circumstances refers to this object in a
Python namespace.
This typically refers to the "key" of the column as present in the
``.c`` collection of a selectable, e.g. ``sometable.c["somekey"]`` would
return a :class:`_schema.Column` with a ``.key`` of "somekey".
"""
@HasMemoized.memoized_attribute
def _tq_key_label(self) -> Optional[str]:
"""A label-based version of 'key' that in some circumstances refers
to this object in a Python namespace.
_tq_key_label comes into play when a select() statement is constructed
with apply_labels(); in this case, all Column objects in the ``.c``
collection are rendered as <tablename>_<columnname> in SQL; this is
essentially the value of ._label. But to locate those columns in the
``.c`` collection, the name is along the lines of <tablename>_<key>;
that's the typical value of .key_label.
.. versionchanged:: 1.4.21 renamed from ``._key_label``
"""
return self._proxy_key
@property
def _key_label(self) -> Optional[str]:
"""legacy; renamed to _tq_key_label"""
return self._tq_key_label
@property
def _label(self) -> Optional[str]:
"""legacy; renamed to _tq_label"""
return self._tq_label
@property
def _non_anon_label(self) -> Optional[str]:
"""the 'name' that naturally applies this element when rendered in
SQL.
Concretely, this is the "name" of a column or a label in a
SELECT statement; ``<columnname>`` and ``<labelname>`` below::
SELECT <columnmame> FROM table
SELECT column AS <labelname> FROM table
Above, the two names noted will be what's present in the DBAPI
``cursor.description`` as the names.
If this attribute returns ``None``, it means that the SQL element as
written does not have a 100% fully predictable "name" that would appear
in the ``cursor.description``. Examples include SQL functions, CAST
functions, etc. While such things do return names in
``cursor.description``, they are only predictable on a
database-specific basis; e.g. an expression like ``MAX(table.col)`` may
appear as the string ``max`` on one database (like PostgreSQL) or may
appear as the whole expression ``max(table.col)`` on SQLite.
The default implementation looks for a ``.name`` attribute on the
object, as has been the precedent established in SQLAlchemy for many
years. An exception is made on the ``FunctionElement`` subclass
so that the return value is always ``None``.
.. versionadded:: 1.4.21
"""
return getattr(self, "name", None)
_render_label_in_columns_clause = True
"""A flag used by select._columns_plus_names that helps to determine
we are actually going to render in terms of "SELECT <col> AS <label>".
This flag can be returned as False for some Column objects that want
to be rendered as simple "SELECT <col>"; typically columns that don't have
any parent table and are named the same as what the label would be
in any case.
"""
_allow_label_resolve = True
"""A flag that can be flipped to prevent a column from being resolvable
by string label name.
The joined eager loader strategy in the ORM uses this, for example.
"""
_is_implicitly_boolean = False
_alt_names: Sequence[str] = ()
@overload
def self_group(
self: ColumnElement[_T], against: Optional[OperatorType] = None
) -> ColumnElement[_T]:
...
@overload
def self_group(
self: ColumnElement[Any], against: Optional[OperatorType] = None
) -> ColumnElement[Any]:
...
def self_group(
self, against: Optional[OperatorType] = None
) -> ColumnElement[Any]:
if (
against in (operators.and_, operators.or_, operators._asbool)
and self.type._type_affinity is type_api.BOOLEANTYPE._type_affinity
):
return AsBoolean(self, operators.is_true, operators.is_false)
elif against in (operators.any_op, operators.all_op):
return Grouping(self)
else:
return self
@overload
def _negate(self: ColumnElement[bool]) -> ColumnElement[bool]:
...
@overload
def _negate(self: ColumnElement[_T]) -> ColumnElement[_T]:
...
def _negate(self) -> ColumnElement[Any]:
if self.type._type_affinity is type_api.BOOLEANTYPE._type_affinity:
return AsBoolean(self, operators.is_false, operators.is_true)
else:
grouped = self.self_group(against=operators.inv)
assert isinstance(grouped, ColumnElement)
return UnaryExpression(
grouped, operator=operators.inv, wraps_column_expression=True
)
type: TypeEngine[_T]
if not TYPE_CHECKING:
@util.memoized_property
def type(self) -> TypeEngine[_T]: # noqa: A001
# used for delayed setup of
# type_api
return type_api.NULLTYPE
@HasMemoized.memoized_attribute
def comparator(self) -> TypeEngine.Comparator[_T]:
try:
comparator_factory = self.type.comparator_factory
except AttributeError as err:
raise TypeError(
"Object %r associated with '.type' attribute "
"is not a TypeEngine class or object" % self.type
) from err
else:
return comparator_factory(self)
def __getattr__(self, key: str) -> Any:
try:
return getattr(self.comparator, key)
except AttributeError as err:
raise AttributeError(
"Neither %r object nor %r object has an attribute %r"
% (
type(self).__name__,
type(self.comparator).__name__,
key,
)
) from err
def operate(
self,
op: operators.OperatorType,
*other: Any,
**kwargs: Any,
) -> ColumnElement[Any]:
return op(self.comparator, *other, **kwargs) # type: ignore[return-value] # noqa: E501
def reverse_operate(
self, op: operators.OperatorType, other: Any, **kwargs: Any
) -> ColumnElement[Any]:
return op(other, self.comparator, **kwargs) # type: ignore[return-value] # noqa: E501
def _bind_param(
self,
operator: operators.OperatorType,
obj: Any,
type_: Optional[TypeEngine[_T]] = None,
expanding: bool = False,
) -> BindParameter[_T]:
return BindParameter(
None,
obj,
_compared_to_operator=operator,
type_=type_,
_compared_to_type=self.type,
unique=True,
expanding=expanding,
)
@property
def expression(self) -> ColumnElement[Any]:
"""Return a column expression.
Part of the inspection interface; returns self.
"""
return self
@property
def _select_iterable(self) -> _SelectIterable:
return (self,)
@util.memoized_property
def base_columns(self) -> FrozenSet[ColumnElement[Any]]:
return frozenset(c for c in self.proxy_set if not c._proxies)
@util.memoized_property
def proxy_set(self) -> FrozenSet[ColumnElement[Any]]:
"""set of all columns we are proxying
as of 2.0 this is explicitly deannotated columns. previously it was
effectively deannotated columns but wasn't enforced. annotated
columns should basically not go into sets if at all possible because
their hashing behavior is very non-performant.
"""
return frozenset([self._deannotate()]).union(
itertools.chain(*[c.proxy_set for c in self._proxies])
)
@util.memoized_property
def _expanded_proxy_set(self) -> FrozenSet[ColumnElement[Any]]:
return frozenset(_expand_cloned(self.proxy_set))
def _uncached_proxy_list(self) -> List[ColumnElement[Any]]:
"""An 'uncached' version of proxy set.
This list includes annotated columns which perform very poorly in
set operations.
"""
return [self] + list(
itertools.chain(*[c._uncached_proxy_list() for c in self._proxies])
)
def shares_lineage(self, othercolumn: ColumnElement[Any]) -> bool:
"""Return True if the given :class:`_expression.ColumnElement`
has a common ancestor to this :class:`_expression.ColumnElement`."""
return bool(self.proxy_set.intersection(othercolumn.proxy_set))
def _compare_name_for_result(self, other: ColumnElement[Any]) -> bool:
"""Return True if the given column element compares to this one
when targeting within a result row."""
return (
hasattr(other, "name")
and hasattr(self, "name")
and other.name == self.name
)
@HasMemoized.memoized_attribute
def _proxy_key(self) -> Optional[str]:
if self._annotations and "proxy_key" in self._annotations:
return cast(str, self._annotations["proxy_key"])
name = self.key
if not name:
# there's a bit of a seeming contradiction which is that the
# "_non_anon_label" of a column can in fact be an
# "_anonymous_label"; this is when it's on a column that is
# proxying for an anonymous expression in a subquery.
name = self._non_anon_label
if isinstance(name, _anonymous_label):
return None
else:
return name
@HasMemoized.memoized_attribute
def _expression_label(self) -> Optional[str]:
"""a suggested label to use in the case that the column has no name,
which should be used if possible as the explicit 'AS <label>'
where this expression would normally have an anon label.
this is essentially mostly what _proxy_key does except it returns
None if the column has a normal name that can be used.
"""
if getattr(self, "name", None) is not None:
return None
elif self._annotations and "proxy_key" in self._annotations:
return cast(str, self._annotations["proxy_key"])
else:
return None
def _make_proxy(
self,
selectable: FromClause,
*,
name: Optional[str] = None,
key: Optional[str] = None,
name_is_truncatable: bool = False,
compound_select_cols: Optional[Sequence[ColumnElement[Any]]] = None,
**kw: Any,
) -> typing_Tuple[str, ColumnClause[_T]]:
"""Create a new :class:`_expression.ColumnElement` representing this
:class:`_expression.ColumnElement` as it appears in the select list of
a descending selectable.
"""
if name is None:
name = self._anon_name_label
if key is None:
key = self._proxy_key
else:
key = name
assert key is not None
co: ColumnClause[_T] = ColumnClause(
coercions.expect(roles.TruncatedLabelRole, name)
if name_is_truncatable
else name,
type_=getattr(self, "type", None),
_selectable=selectable,
)
co._propagate_attrs = selectable._propagate_attrs
if compound_select_cols:
co._proxies = list(compound_select_cols)
else:
co._proxies = [self]
if selectable._is_clone_of is not None:
co._is_clone_of = selectable._is_clone_of.columns.get(key)
return key, co
def cast(self, type_: _TypeEngineArgument[_OPT]) -> Cast[_OPT]:
"""Produce a type cast, i.e. ``CAST(<expression> AS <type>)``.
This is a shortcut to the :func:`_expression.cast` function.
.. seealso::
:ref:`tutorial_casts`
:func:`_expression.cast`
:func:`_expression.type_coerce`
.. versionadded:: 1.0.7
"""
return Cast(self, type_)
def label(self, name: Optional[str]) -> Label[_T]:
"""Produce a column label, i.e. ``<columnname> AS <name>``.
This is a shortcut to the :func:`_expression.label` function.
If 'name' is ``None``, an anonymous label name will be generated.
"""
return Label(name, self, self.type)
def _anon_label(
self, seed: Optional[str], add_hash: Optional[int] = None
) -> _anonymous_label:
while self._is_clone_of is not None:
self = self._is_clone_of
# as of 1.4 anonymous label for ColumnElement uses hash(), not id(),
# as the identifier, because a column and its annotated version are
# the same thing in a SQL statement
hash_value = hash(self)
if add_hash:
# this path is used for disambiguating anon labels that would
# otherwise be the same name for the same element repeated.
# an additional numeric value is factored in for each label.
# shift hash(self) (which is id(self), typically 8 byte integer)
# 16 bits leftward. fill extra add_hash on right
assert add_hash < (2 << 15)
assert seed
hash_value = (hash_value << 16) | add_hash
# extra underscore is added for labels with extra hash
# values, to isolate the "deduped anon" namespace from the
# regular namespace. eliminates chance of these
# manufactured hash values overlapping with regular ones for some
# undefined python interpreter
seed = seed + "_"
if isinstance(seed, _anonymous_label):
return _anonymous_label.safe_construct(
hash_value, "", enclosing_label=seed
)
return _anonymous_label.safe_construct(hash_value, seed or "anon")
@util.memoized_property
def _anon_name_label(self) -> str:
"""Provides a constant 'anonymous label' for this ColumnElement.
This is a label() expression which will be named at compile time.
The same label() is returned each time ``anon_label`` is called so
that expressions can reference ``anon_label`` multiple times,
producing the same label name at compile time.
The compiler uses this function automatically at compile time
for expressions that are known to be 'unnamed' like binary
expressions and function calls.
.. versionchanged:: 1.4.9 - this attribute was not intended to be
public and is renamed to _anon_name_label. anon_name exists
for backwards compat
"""
name = getattr(self, "name", None)
return self._anon_label(name)
@util.memoized_property
def _anon_key_label(self) -> _anonymous_label:
"""Provides a constant 'anonymous key label' for this ColumnElement.
Compare to ``anon_label``, except that the "key" of the column,
if available, is used to generate the label.
This is used when a deduplicating key is placed into the columns
collection of a selectable.
.. versionchanged:: 1.4.9 - this attribute was not intended to be
public and is renamed to _anon_key_label. anon_key_label exists
for backwards compat
"""
return self._anon_label(self._proxy_key)
@property
@util.deprecated(
"1.4",
"The :attr:`_expression.ColumnElement.anon_label` attribute is now "
"private, and the public accessor is deprecated.",
)
def anon_label(self) -> str:
return self._anon_name_label
@property
@util.deprecated(
"1.4",
"The :attr:`_expression.ColumnElement.anon_key_label` attribute is "
"now private, and the public accessor is deprecated.",
)
def anon_key_label(self) -> str:
return self._anon_key_label
def _dedupe_anon_label_idx(self, idx: int) -> str:
"""label to apply to a column that is anon labeled, but repeated
in the SELECT, so that we have to make an "extra anon" label that
disambiguates it from the previous appearance.
these labels come out like "foo_bar_id__1" and have double underscores
in them.
"""
label = getattr(self, "name", None)
# current convention is that if the element doesn't have a
# ".name" (usually because it is not NamedColumn), we try to
# use a "table qualified" form for the "dedupe anon" label,
# based on the notion that a label like
# "CAST(casttest.v1 AS DECIMAL) AS casttest_v1__1" looks better than
# "CAST(casttest.v1 AS DECIMAL) AS anon__1"
if label is None:
return self._dedupe_anon_tq_label_idx(idx)
else:
return self._anon_label(label, add_hash=idx)
@util.memoized_property
def _anon_tq_label(self) -> _anonymous_label:
return self._anon_label(getattr(self, "_tq_label", None))
@util.memoized_property
def _anon_tq_key_label(self) -> _anonymous_label:
return self._anon_label(getattr(self, "_tq_key_label", None))
def _dedupe_anon_tq_label_idx(self, idx: int) -> _anonymous_label:
label = getattr(self, "_tq_label", None) or "anon"
return self._anon_label(label, add_hash=idx)
class KeyedColumnElement(ColumnElement[_T]):
"""ColumnElement where ``.key`` is non-None."""
_is_keyed_column_element = True
key: str
class WrapsColumnExpression(ColumnElement[_T]):
"""Mixin that defines a :class:`_expression.ColumnElement`
as a wrapper with special
labeling behavior for an expression that already has a name.
.. versionadded:: 1.4
.. seealso::
:ref:`change_4449`
"""
@property
def wrapped_column_expression(self) -> ColumnElement[_T]:
raise NotImplementedError()
@util.non_memoized_property
def _tq_label(self) -> Optional[str]:
wce = self.wrapped_column_expression
if hasattr(wce, "_tq_label"):
return wce._tq_label
else:
return None
@property
def _label(self) -> Optional[str]:
return self._tq_label
@property
def _non_anon_label(self) -> Optional[str]:
return None
@util.non_memoized_property
def _anon_name_label(self) -> str:
wce = self.wrapped_column_expression
# this logic tries to get the WrappedColumnExpression to render
# with "<expr> AS <name>", where "<name>" is the natural name
# within the expression itself. e.g. "CAST(table.foo) AS foo".
if not wce._is_text_clause:
nal = wce._non_anon_label
if nal:
return nal
elif hasattr(wce, "_anon_name_label"):
return wce._anon_name_label
return super()._anon_name_label
def _dedupe_anon_label_idx(self, idx: int) -> str:
wce = self.wrapped_column_expression
nal = wce._non_anon_label
if nal:
return self._anon_label(nal + "_")
else:
return self._dedupe_anon_tq_label_idx(idx)
@property
def _proxy_key(self):
wce = self.wrapped_column_expression
if not wce._is_text_clause:
return wce._proxy_key
return super()._proxy_key
class BindParameter(roles.InElementRole, KeyedColumnElement[_T]):
r"""Represent a "bound expression".
:class:`.BindParameter` is invoked explicitly using the
:func:`.bindparam` function, as in::
from sqlalchemy import bindparam
stmt = select(users_table).\
where(users_table.c.name == bindparam('username'))
Detailed discussion of how :class:`.BindParameter` is used is
at :func:`.bindparam`.
.. seealso::
:func:`.bindparam`
"""
__visit_name__ = "bindparam"
_traverse_internals: _TraverseInternalsType = [
("key", InternalTraversal.dp_anon_name),
("type", InternalTraversal.dp_type),
("callable", InternalTraversal.dp_plain_dict),
("value", InternalTraversal.dp_plain_obj),
("literal_execute", InternalTraversal.dp_boolean),
]
key: str
type: TypeEngine[_T]
value: Optional[_T]
_is_crud = False
_is_bind_parameter = True
_key_is_anon = False
# bindparam implements its own _gen_cache_key() method however
# we check subclasses for this flag, else no cache key is generated
inherit_cache = True
def __init__(
self,
key: Optional[str],
value: Any = _NoArg.NO_ARG,
type_: Optional[_TypeEngineArgument[_T]] = None,
unique: bool = False,
required: Union[bool, Literal[_NoArg.NO_ARG]] = _NoArg.NO_ARG,
quote: Optional[bool] = None,
callable_: Optional[Callable[[], Any]] = None,
expanding: bool = False,
isoutparam: bool = False,
literal_execute: bool = False,
_compared_to_operator: Optional[OperatorType] = None,
_compared_to_type: Optional[TypeEngine[Any]] = None,
_is_crud: bool = False,
):
if required is _NoArg.NO_ARG:
required = value is _NoArg.NO_ARG and callable_ is None
if value is _NoArg.NO_ARG:
value = None
if quote is not None:
key = quoted_name.construct(key, quote)
if unique:
self.key = _anonymous_label.safe_construct(
id(self),
key
if key is not None and not isinstance(key, _anonymous_label)
else "param",
sanitize_key=True,
)
self._key_is_anon = True
elif key:
self.key = key
else:
self.key = _anonymous_label.safe_construct(id(self), "param")
self._key_is_anon = True
# identifying key that won't change across
# clones, used to identify the bind's logical
# identity
self._identifying_key = self.key
# key that was passed in the first place, used to
# generate new keys
self._orig_key = key or "param"
self.unique = unique
self.value = value
self.callable = callable_
self.isoutparam = isoutparam
self.required = required
# indicate an "expanding" parameter; the compiler sets this
# automatically in the compiler _render_in_expr_w_bindparam method
# for an IN expression
self.expanding = expanding
# this is another hint to help w/ expanding and is typically
# set in the compiler _render_in_expr_w_bindparam method for an
# IN expression
self.expand_op = None
self.literal_execute = literal_execute
if _is_crud:
self._is_crud = True
if type_ is None:
if expanding:
if value:
check_value = value[0]
else:
check_value = type_api._NO_VALUE_IN_LIST
else:
check_value = value
if _compared_to_type is not None:
self.type = _compared_to_type.coerce_compared_value(
_compared_to_operator, check_value
)
else:
self.type = type_api._resolve_value_to_type(check_value)
elif isinstance(type_, type):
self.type = type_()
elif is_tuple_type(type_):
if value:
if expanding:
check_value = value[0]
else:
check_value = value
cast(
"BindParameter[typing_Tuple[Any, ...]]", self
).type = type_._resolve_values_to_types(check_value)
else:
cast(
"BindParameter[typing_Tuple[Any, ...]]", self
).type = type_
else:
self.type = type_
def _with_value(self, value, maintain_key=False, required=NO_ARG):
"""Return a copy of this :class:`.BindParameter` with the given value
set.
"""
cloned = self._clone(maintain_key=maintain_key)
cloned.value = value
cloned.callable = None
cloned.required = required if required is not NO_ARG else self.required
if cloned.type is type_api.NULLTYPE:
cloned.type = type_api._resolve_value_to_type(value)
return cloned
@property
def effective_value(self) -> Optional[_T]:
"""Return the value of this bound parameter,
taking into account if the ``callable`` parameter
was set.
The ``callable`` value will be evaluated
and returned if present, else ``value``.
"""
if self.callable:
# TODO: set up protocol for bind parameter callable
return self.callable() # type: ignore
else:
return self.value
def render_literal_execute(self) -> BindParameter[_T]:
"""Produce a copy of this bound parameter that will enable the
:paramref:`_sql.BindParameter.literal_execute` flag.
The :paramref:`_sql.BindParameter.literal_execute` flag will
have the effect of the parameter rendered in the compiled SQL
string using ``[POSTCOMPILE]`` form, which is a special form that
is converted to be a rendering of the literal value of the parameter
at SQL execution time. The rationale is to support caching
of SQL statement strings that can embed per-statement literal values,
such as LIMIT and OFFSET parameters, in the final SQL string that
is passed to the DBAPI. Dialects in particular may want to use
this method within custom compilation schemes.
.. versionadded:: 1.4.5
.. seealso::
:ref:`engine_thirdparty_caching`
"""
return self.__class__(
self.key,
self.value,
type_=self.type,
literal_execute=True,
)
def _negate_in_binary(self, negated_op, original_op):
if self.expand_op is original_op:
bind = self._clone()
bind.expand_op = negated_op
return bind
else:
return self
def _with_binary_element_type(self, type_):
c = ClauseElement._clone(self)
c.type = type_
return c
def _clone(self, maintain_key: bool = False, **kw: Any) -> Self:
c = ClauseElement._clone(self, **kw)
# ensure all the BindParameter objects stay in cloned set.
# in #7823, we changed "clone" so that a clone only keeps a reference
# to the "original" element, since for column correspondence, that's
# all we need. However, for BindParam, _cloned_set is used by
# the "cache key bind match" lookup, which means if any of those
# interim BindParameter objects became part of a cache key in the
# cache, we need it. So here, make sure all clones keep carrying
# forward.
c._cloned_set.update(self._cloned_set)
if not maintain_key and self.unique:
c.key = _anonymous_label.safe_construct(
id(c), c._orig_key or "param", sanitize_key=True
)
return c
def _gen_cache_key(self, anon_map, bindparams):
_gen_cache_ok = self.__class__.__dict__.get("inherit_cache", False)
if not _gen_cache_ok:
if anon_map is not None:
anon_map[NO_CACHE] = True
return None
id_, found = anon_map.get_anon(self)
if found:
return (id_, self.__class__)
if bindparams is not None:
bindparams.append(self)
return (
id_,
self.__class__,
self.type._static_cache_key,
self.key % anon_map if self._key_is_anon else self.key,
self.literal_execute,
)
def _convert_to_unique(self):
if not self.unique:
self.unique = True
self.key = _anonymous_label.safe_construct(
id(self), self._orig_key or "param", sanitize_key=True
)
def __getstate__(self):
"""execute a deferred value for serialization purposes."""
d = self.__dict__.copy()
v = self.value
if self.callable:
v = self.callable()
d["callable"] = None
d["value"] = v
return d
def __setstate__(self, state):
if state.get("unique", False):
state["key"] = _anonymous_label.safe_construct(
id(self), state.get("_orig_key", "param"), sanitize_key=True
)
self.__dict__.update(state)
def __repr__(self):
return "%s(%r, %r, type_=%r)" % (
self.__class__.__name__,
self.key,
self.value,
self.type,
)
class TypeClause(DQLDMLClauseElement):
"""Handle a type keyword in a SQL statement.
Used by the ``Case`` statement.
"""
__visit_name__ = "typeclause"
_traverse_internals: _TraverseInternalsType = [
("type", InternalTraversal.dp_type)
]
def __init__(self, type_):
self.type = type_
class TextClause(
roles.DDLConstraintColumnRole,
roles.DDLExpressionRole,
roles.StatementOptionRole,
roles.WhereHavingRole,
roles.OrderByRole,
roles.FromClauseRole,
roles.SelectStatementRole,
roles.InElementRole,
Generative,
Executable,
DQLDMLClauseElement,
roles.BinaryElementRole[Any],
inspection.Inspectable["TextClause"],
):
"""Represent a literal SQL text fragment.
E.g.::
from sqlalchemy import text
t = text("SELECT * FROM users")
result = connection.execute(t)
The :class:`_expression.TextClause` construct is produced using the
:func:`_expression.text`
function; see that function for full documentation.
.. seealso::
:func:`_expression.text`
"""
__visit_name__ = "textclause"
_traverse_internals: _TraverseInternalsType = [
("_bindparams", InternalTraversal.dp_string_clauseelement_dict),
("text", InternalTraversal.dp_string),
]
_is_text_clause = True
_is_textual = True
_bind_params_regex = re.compile(r"(?<![:\w\x5c]):(\w+)(?!:)", re.UNICODE)
_is_implicitly_boolean = False
_render_label_in_columns_clause = False
@property
def _hide_froms(self) -> Iterable[FromClause]:
return ()
def __and__(self, other):
# support use in select.where(), query.filter()
return and_(self, other)
@property
def _select_iterable(self) -> _SelectIterable:
return (self,)
# help in those cases where text() is
# interpreted in a column expression situation
key: Optional[str] = None
_label: Optional[str] = None
_allow_label_resolve = False
@property
def _is_star(self):
return self.text == "*"
def __init__(self, text: str):
self._bindparams: Dict[str, BindParameter[Any]] = {}
def repl(m):
self._bindparams[m.group(1)] = BindParameter(m.group(1))
return ":%s" % m.group(1)
# scan the string and search for bind parameter names, add them
# to the list of bindparams
self.text = self._bind_params_regex.sub(repl, text)
@_generative
def bindparams(
self,
*binds: BindParameter[Any],
**names_to_values: Any,
) -> Self:
"""Establish the values and/or types of bound parameters within
this :class:`_expression.TextClause` construct.
Given a text construct such as::
from sqlalchemy import text
stmt = text("SELECT id, name FROM user WHERE name=:name "
"AND timestamp=:timestamp")
the :meth:`_expression.TextClause.bindparams`
method can be used to establish
the initial value of ``:name`` and ``:timestamp``,
using simple keyword arguments::
stmt = stmt.bindparams(name='jack',
timestamp=datetime.datetime(2012, 10, 8, 15, 12, 5))
Where above, new :class:`.BindParameter` objects
will be generated with the names ``name`` and ``timestamp``, and
values of ``jack`` and ``datetime.datetime(2012, 10, 8, 15, 12, 5)``,
respectively. The types will be
inferred from the values given, in this case :class:`.String` and
:class:`.DateTime`.
When specific typing behavior is needed, the positional ``*binds``
argument can be used in which to specify :func:`.bindparam` constructs
directly. These constructs must include at least the ``key``
argument, then an optional value and type::
from sqlalchemy import bindparam
stmt = stmt.bindparams(
bindparam('name', value='jack', type_=String),
bindparam('timestamp', type_=DateTime)
)
Above, we specified the type of :class:`.DateTime` for the
``timestamp`` bind, and the type of :class:`.String` for the ``name``
bind. In the case of ``name`` we also set the default value of
``"jack"``.
Additional bound parameters can be supplied at statement execution
time, e.g.::
result = connection.execute(stmt,
timestamp=datetime.datetime(2012, 10, 8, 15, 12, 5))
The :meth:`_expression.TextClause.bindparams`
method can be called repeatedly,
where it will re-use existing :class:`.BindParameter` objects to add
new information. For example, we can call
:meth:`_expression.TextClause.bindparams`
first with typing information, and a
second time with value information, and it will be combined::
stmt = text("SELECT id, name FROM user WHERE name=:name "
"AND timestamp=:timestamp")
stmt = stmt.bindparams(
bindparam('name', type_=String),
bindparam('timestamp', type_=DateTime)
)
stmt = stmt.bindparams(
name='jack',
timestamp=datetime.datetime(2012, 10, 8, 15, 12, 5)
)
The :meth:`_expression.TextClause.bindparams`
method also supports the concept of
**unique** bound parameters. These are parameters that are
"uniquified" on name at statement compilation time, so that multiple
:func:`_expression.text`
constructs may be combined together without the names
conflicting. To use this feature, specify the
:paramref:`.BindParameter.unique` flag on each :func:`.bindparam`
object::
stmt1 = text("select id from table where name=:name").bindparams(
bindparam("name", value='name1', unique=True)
)
stmt2 = text("select id from table where name=:name").bindparams(
bindparam("name", value='name2', unique=True)
)
union = union_all(
stmt1.columns(column("id")),
stmt2.columns(column("id"))
)
The above statement will render as::
select id from table where name=:name_1
UNION ALL select id from table where name=:name_2
.. versionadded:: 1.3.11 Added support for the
:paramref:`.BindParameter.unique` flag to work with
:func:`_expression.text`
constructs.
"""
self._bindparams = new_params = self._bindparams.copy()
for bind in binds:
try:
# the regex used for text() currently will not match
# a unique/anonymous key in any case, so use the _orig_key
# so that a text() construct can support unique parameters
existing = new_params[bind._orig_key]
except KeyError as err:
raise exc.ArgumentError(
"This text() construct doesn't define a "
"bound parameter named %r" % bind._orig_key
) from err
else:
new_params[existing._orig_key] = bind
for key, value in names_to_values.items():
try:
existing = new_params[key]
except KeyError as err:
raise exc.ArgumentError(
"This text() construct doesn't define a "
"bound parameter named %r" % key
) from err
else:
new_params[key] = existing._with_value(value, required=False)
return self
@util.preload_module("sqlalchemy.sql.selectable")
def columns(
self, *cols: _ColumnExpressionArgument[Any], **types: TypeEngine[Any]
) -> TextualSelect:
r"""Turn this :class:`_expression.TextClause` object into a
:class:`_expression.TextualSelect`
object that serves the same role as a SELECT
statement.
The :class:`_expression.TextualSelect` is part of the
:class:`_expression.SelectBase`
hierarchy and can be embedded into another statement by using the
:meth:`_expression.TextualSelect.subquery` method to produce a
:class:`.Subquery`
object, which can then be SELECTed from.
This function essentially bridges the gap between an entirely
textual SELECT statement and the SQL expression language concept
of a "selectable"::
from sqlalchemy.sql import column, text
stmt = text("SELECT id, name FROM some_table")
stmt = stmt.columns(column('id'), column('name')).subquery('st')
stmt = select(mytable).\
select_from(
mytable.join(stmt, mytable.c.name == stmt.c.name)
).where(stmt.c.id > 5)
Above, we pass a series of :func:`_expression.column` elements to the
:meth:`_expression.TextClause.columns` method positionally. These
:func:`_expression.column`
elements now become first class elements upon the
:attr:`_expression.TextualSelect.selected_columns` column collection,
which then
become part of the :attr:`.Subquery.c` collection after
:meth:`_expression.TextualSelect.subquery` is invoked.
The column expressions we pass to
:meth:`_expression.TextClause.columns` may
also be typed; when we do so, these :class:`.TypeEngine` objects become
the effective return type of the column, so that SQLAlchemy's
result-set-processing systems may be used on the return values.
This is often needed for types such as date or boolean types, as well
as for unicode processing on some dialect configurations::
stmt = text("SELECT id, name, timestamp FROM some_table")
stmt = stmt.columns(
column('id', Integer),
column('name', Unicode),
column('timestamp', DateTime)
)
for id, name, timestamp in connection.execute(stmt):
print(id, name, timestamp)
As a shortcut to the above syntax, keyword arguments referring to
types alone may be used, if only type conversion is needed::
stmt = text("SELECT id, name, timestamp FROM some_table")
stmt = stmt.columns(
id=Integer,
name=Unicode,
timestamp=DateTime
)
for id, name, timestamp in connection.execute(stmt):
print(id, name, timestamp)
The positional form of :meth:`_expression.TextClause.columns`
also provides the
unique feature of **positional column targeting**, which is
particularly useful when using the ORM with complex textual queries. If
we specify the columns from our model to
:meth:`_expression.TextClause.columns`,
the result set will match to those columns positionally, meaning the
name or origin of the column in the textual SQL doesn't matter::
stmt = text("SELECT users.id, addresses.id, users.id, "
"users.name, addresses.email_address AS email "
"FROM users JOIN addresses ON users.id=addresses.user_id "
"WHERE users.id = 1").columns(
User.id,
Address.id,
Address.user_id,
User.name,
Address.email_address
)
query = session.query(User).from_statement(stmt).options(
contains_eager(User.addresses))
.. versionadded:: 1.1 the :meth:`_expression.TextClause.columns`
method now
offers positional column targeting in the result set when
the column expressions are passed purely positionally.
The :meth:`_expression.TextClause.columns` method provides a direct
route to calling :meth:`_expression.FromClause.subquery` as well as
:meth:`_expression.SelectBase.cte`
against a textual SELECT statement::
stmt = stmt.columns(id=Integer, name=String).cte('st')
stmt = select(sometable).where(sometable.c.id == stmt.c.id)
:param \*cols: A series of :class:`_expression.ColumnElement` objects,
typically
:class:`_schema.Column` objects from a :class:`_schema.Table`
or ORM level
column-mapped attributes, representing a set of columns that this
textual string will SELECT from.
:param \**types: A mapping of string names to :class:`.TypeEngine`
type objects indicating the datatypes to use for names that are
SELECTed from the textual string. Prefer to use the ``*cols``
argument as it also indicates positional ordering.
"""
selectable = util.preloaded.sql_selectable
input_cols: List[NamedColumn[Any]] = [
coercions.expect(roles.LabeledColumnExprRole, col) for col in cols
]
positional_input_cols = [
ColumnClause(col.key, types.pop(col.key))
if col.key in types
else col
for col in input_cols
]
keyed_input_cols: List[NamedColumn[Any]] = [
ColumnClause(key, type_) for key, type_ in types.items()
]
elem = selectable.TextualSelect.__new__(selectable.TextualSelect)
elem._init(
self,
positional_input_cols + keyed_input_cols,
positional=bool(positional_input_cols) and not keyed_input_cols,
)
return elem
@property
def type(self) -> TypeEngine[Any]:
return type_api.NULLTYPE
@property
def comparator(self):
# TODO: this seems wrong, it seems like we might not
# be using this method.
return self.type.comparator_factory(self) # type: ignore
def self_group(self, against=None):
if against is operators.in_op:
return Grouping(self)
else:
return self
class Null(SingletonConstant, roles.ConstExprRole[None], ColumnElement[None]):
"""Represent the NULL keyword in a SQL statement.
:class:`.Null` is accessed as a constant via the
:func:`.null` function.
"""
__visit_name__ = "null"
_traverse_internals: _TraverseInternalsType = []
_singleton: Null
@util.memoized_property
def type(self):
return type_api.NULLTYPE
@classmethod
def _instance(cls) -> Null:
"""Return a constant :class:`.Null` construct."""
return Null._singleton
Null._create_singleton()
class False_(
SingletonConstant, roles.ConstExprRole[bool], ColumnElement[bool]
):
"""Represent the ``false`` keyword, or equivalent, in a SQL statement.
:class:`.False_` is accessed as a constant via the
:func:`.false` function.
"""
__visit_name__ = "false"
_traverse_internals: _TraverseInternalsType = []
_singleton: False_
@util.memoized_property
def type(self):
return type_api.BOOLEANTYPE
def _negate(self) -> True_:
return True_._singleton
@classmethod
def _instance(cls) -> False_:
return False_._singleton
False_._create_singleton()
class True_(SingletonConstant, roles.ConstExprRole[bool], ColumnElement[bool]):
"""Represent the ``true`` keyword, or equivalent, in a SQL statement.
:class:`.True_` is accessed as a constant via the
:func:`.true` function.
"""
__visit_name__ = "true"
_traverse_internals: _TraverseInternalsType = []
_singleton: True_
@util.memoized_property
def type(self):
return type_api.BOOLEANTYPE
def _negate(self) -> False_:
return False_._singleton
@classmethod
def _ifnone(
cls, other: Optional[ColumnElement[Any]]
) -> ColumnElement[Any]:
if other is None:
return cls._instance()
else:
return other
@classmethod
def _instance(cls) -> True_:
return True_._singleton
True_._create_singleton()
class ClauseList(
roles.InElementRole,
roles.OrderByRole,
roles.ColumnsClauseRole,
roles.DMLColumnRole,
DQLDMLClauseElement,
):
"""Describe a list of clauses, separated by an operator.
By default, is comma-separated, such as a column listing.
"""
__visit_name__ = "clauselist"
# this is used only by the ORM in a legacy use case for
# composite attributes
_is_clause_list = True
_traverse_internals: _TraverseInternalsType = [
("clauses", InternalTraversal.dp_clauseelement_list),
("operator", InternalTraversal.dp_operator),
]
clauses: List[ColumnElement[Any]]
def __init__(
self,
*clauses: _ColumnExpressionArgument[Any],
operator: OperatorType = operators.comma_op,
group: bool = True,
group_contents: bool = True,
_literal_as_text_role: Type[roles.SQLRole] = roles.WhereHavingRole,
):
self.operator = operator
self.group = group
self.group_contents = group_contents
clauses_iterator: Iterable[_ColumnExpressionArgument[Any]] = clauses
text_converter_role: Type[roles.SQLRole] = _literal_as_text_role
self._text_converter_role = text_converter_role
if self.group_contents:
self.clauses = [
coercions.expect(
text_converter_role, clause, apply_propagate_attrs=self
).self_group(against=self.operator)
for clause in clauses_iterator
]
else:
self.clauses = [
coercions.expect(
text_converter_role, clause, apply_propagate_attrs=self
)
for clause in clauses_iterator
]
self._is_implicitly_boolean = operators.is_boolean(self.operator)
@classmethod
def _construct_raw(
cls,
operator: OperatorType,
clauses: Optional[Sequence[ColumnElement[Any]]] = None,
) -> ClauseList:
self = cls.__new__(cls)
self.clauses = list(clauses) if clauses else []
self.group = True
self.operator = operator
self.group_contents = True
self._is_implicitly_boolean = False
return self
def __iter__(self) -> Iterator[ColumnElement[Any]]:
return iter(self.clauses)
def __len__(self) -> int:
return len(self.clauses)
@property
def _select_iterable(self) -> _SelectIterable:
return itertools.chain.from_iterable(
[elem._select_iterable for elem in self.clauses]
)
def append(self, clause):
if self.group_contents:
self.clauses.append(
coercions.expect(self._text_converter_role, clause).self_group(
against=self.operator
)
)
else:
self.clauses.append(
coercions.expect(self._text_converter_role, clause)
)
@util.ro_non_memoized_property
def _from_objects(self) -> List[FromClause]:
return list(itertools.chain(*[c._from_objects for c in self.clauses]))
def self_group(self, against=None):
if self.group and operators.is_precedent(self.operator, against):
return Grouping(self)
else:
return self
class OperatorExpression(ColumnElement[_T]):
"""base for expressions that contain an operator and operands
.. versionadded:: 2.0
"""
operator: OperatorType
type: TypeEngine[_T]
group: bool = True
@property
def is_comparison(self):
return operators.is_comparison(self.operator)
def self_group(self, against=None):
if (
self.group
and operators.is_precedent(self.operator, against)
or (
# a negate against a non-boolean operator
# doesn't make too much sense but we should
# group for that
against is operators.inv
and not operators.is_boolean(self.operator)
)
):
return Grouping(self)
else:
return self
@property
def _flattened_operator_clauses(
self,
) -> typing_Tuple[ColumnElement[Any], ...]:
raise NotImplementedError()
@classmethod
def _construct_for_op(
cls,
left: ColumnElement[Any],
right: ColumnElement[Any],
op: OperatorType,
*,
type_: TypeEngine[_T],
negate: Optional[OperatorType] = None,
modifiers: Optional[Mapping[str, Any]] = None,
) -> OperatorExpression[_T]:
if operators.is_associative(op):
assert (
negate is None
), f"negate not supported for associative operator {op}"
multi = False
if getattr(
left, "operator", None
) is op and type_._compare_type_affinity(left.type):
multi = True
left_flattened = left._flattened_operator_clauses
else:
left_flattened = (left,)
if getattr(
right, "operator", None
) is op and type_._compare_type_affinity(right.type):
multi = True
right_flattened = right._flattened_operator_clauses
else:
right_flattened = (right,)
if multi:
return ExpressionClauseList._construct_for_list(
op,
type_,
*(left_flattened + right_flattened),
)
return BinaryExpression(
left, right, op, type_=type_, negate=negate, modifiers=modifiers
)
class ExpressionClauseList(OperatorExpression[_T]):
"""Describe a list of clauses, separated by an operator,
in a column expression context.
:class:`.ExpressionClauseList` differs from :class:`.ClauseList` in that
it represents a column-oriented DQL expression only, not an open ended
list of anything comma separated.
.. versionadded:: 2.0
"""
__visit_name__ = "expression_clauselist"
_traverse_internals: _TraverseInternalsType = [
("clauses", InternalTraversal.dp_clauseelement_tuple),
("operator", InternalTraversal.dp_operator),
]
clauses: typing_Tuple[ColumnElement[Any], ...]
group: bool
def __init__(
self,
operator: OperatorType,
*clauses: _ColumnExpressionArgument[Any],
type_: Optional[_TypeEngineArgument[_T]] = None,
):
self.operator = operator
self.clauses = tuple(
coercions.expect(
roles.ExpressionElementRole, clause, apply_propagate_attrs=self
)
for clause in clauses
)
self._is_implicitly_boolean = operators.is_boolean(self.operator)
self.type = type_api.to_instance(type_) # type: ignore
@property
def _flattened_operator_clauses(
self,
) -> typing_Tuple[ColumnElement[Any], ...]:
return self.clauses
def __iter__(self) -> Iterator[ColumnElement[Any]]:
return iter(self.clauses)
def __len__(self) -> int:
return len(self.clauses)
@property
def _select_iterable(self) -> _SelectIterable:
return (self,)
@util.ro_non_memoized_property
def _from_objects(self) -> List[FromClause]:
return list(itertools.chain(*[c._from_objects for c in self.clauses]))
def _append_inplace(self, clause: ColumnElement[Any]) -> None:
self.clauses += (clause,)
@classmethod
def _construct_for_list(
cls,
operator: OperatorType,
type_: TypeEngine[_T],
*clauses: ColumnElement[Any],
group: bool = True,
) -> ExpressionClauseList[_T]:
self = cls.__new__(cls)
self.group = group
if group:
self.clauses = tuple(
c.self_group(against=operator) for c in clauses
)
else:
self.clauses = clauses
self.operator = operator
self.type = type_
return self
def _negate(self) -> Any:
grouped = self.self_group(against=operators.inv)
assert isinstance(grouped, ColumnElement)
return UnaryExpression(
grouped, operator=operators.inv, wraps_column_expression=True
)
class BooleanClauseList(ExpressionClauseList[bool]):
__visit_name__ = "expression_clauselist"
inherit_cache = True
def __init__(self, *arg, **kw):
raise NotImplementedError(
"BooleanClauseList has a private constructor"
)
@classmethod
def _process_clauses_for_boolean(
cls,
operator: OperatorType,
continue_on: Any,
skip_on: Any,
clauses: Iterable[ColumnElement[Any]],
) -> typing_Tuple[int, List[ColumnElement[Any]]]:
has_continue_on = None
convert_clauses = []
against = operators._asbool
lcc = 0
for clause in clauses:
if clause is continue_on:
# instance of continue_on, like and_(x, y, True, z), store it
# if we didn't find one already, we will use it if there
# are no other expressions here.
has_continue_on = clause
elif clause is skip_on:
# instance of skip_on, e.g. and_(x, y, False, z), cancels
# the rest out
convert_clauses = [clause]
lcc = 1
break
else:
if not lcc:
lcc = 1
else:
against = operator
# technically this would be len(convert_clauses) + 1
# however this only needs to indicate "greater than one"
lcc = 2
convert_clauses.append(clause)
if not convert_clauses and has_continue_on is not None:
convert_clauses = [has_continue_on]
lcc = 1
return lcc, [c.self_group(against=against) for c in convert_clauses]
@classmethod
def _construct(
cls,
operator: OperatorType,
continue_on: Any,
skip_on: Any,
initial_clause: Any = _NoArg.NO_ARG,
*clauses: Any,
**kw: Any,
) -> ColumnElement[Any]:
if initial_clause is _NoArg.NO_ARG:
# no elements period. deprecated use case. return an empty
# ClauseList construct that generates nothing unless it has
# elements added to it.
name = operator.__name__
util.warn_deprecated(
f"Invoking {name}() without arguments is deprecated, and "
f"will be disallowed in a future release. For an empty "
f"""{name}() construct, use '{name}({
'true()' if continue_on is True_._singleton else 'false()'
}, *args)' """
f"""or '{name}({
'True' if continue_on is True_._singleton else 'False'
}, *args)'.""",
version="1.4",
)
return cls._construct_raw(operator) # type: ignore[no-any-return]
lcc, convert_clauses = cls._process_clauses_for_boolean(
operator,
continue_on,
skip_on,
[
coercions.expect(roles.WhereHavingRole, clause)
for clause in util.coerce_generator_arg(
(initial_clause,) + clauses
)
],
)
if lcc > 1:
# multiple elements. Return regular BooleanClauseList
# which will link elements against the operator.
flattened_clauses = itertools.chain.from_iterable(
(c for c in to_flat._flattened_operator_clauses)
if getattr(to_flat, "operator", None) is operator
else (to_flat,)
for to_flat in convert_clauses
)
return cls._construct_raw(operator, flattened_clauses) # type: ignore # noqa: E501
else:
assert lcc
# just one element. return it as a single boolean element,
# not a list and discard the operator.
return convert_clauses[0] # type: ignore[no-any-return] # noqa: E501
@classmethod
def _construct_for_whereclause(
cls, clauses: Iterable[ColumnElement[Any]]
) -> Optional[ColumnElement[bool]]:
operator, continue_on, skip_on = (
operators.and_,
True_._singleton,
False_._singleton,
)
lcc, convert_clauses = cls._process_clauses_for_boolean(
operator,
continue_on,
skip_on,
clauses, # these are assumed to be coerced already
)
if lcc > 1:
# multiple elements. Return regular BooleanClauseList
# which will link elements against the operator.
return cls._construct_raw(operator, convert_clauses)
elif lcc == 1:
# just one element. return it as a single boolean element,
# not a list and discard the operator.
return convert_clauses[0]
else:
return None
@classmethod
def _construct_raw(
cls,
operator: OperatorType,
clauses: Optional[Sequence[ColumnElement[Any]]] = None,
) -> BooleanClauseList:
self = cls.__new__(cls)
self.clauses = tuple(clauses) if clauses else ()
self.group = True
self.operator = operator
self.type = type_api.BOOLEANTYPE
self._is_implicitly_boolean = True
return self
@classmethod
def and_(
cls,
initial_clause: Union[
Literal[True], _ColumnExpressionArgument[bool], _NoArg
] = _NoArg.NO_ARG,
*clauses: _ColumnExpressionArgument[bool],
) -> ColumnElement[bool]:
r"""Produce a conjunction of expressions joined by ``AND``.
See :func:`_sql.and_` for full documentation.
"""
return cls._construct(
operators.and_,
True_._singleton,
False_._singleton,
initial_clause,
*clauses,
)
@classmethod
def or_(
cls,
initial_clause: Union[
Literal[False], _ColumnExpressionArgument[bool], _NoArg
] = _NoArg.NO_ARG,
*clauses: _ColumnExpressionArgument[bool],
) -> ColumnElement[bool]:
"""Produce a conjunction of expressions joined by ``OR``.
See :func:`_sql.or_` for full documentation.
"""
return cls._construct(
operators.or_,
False_._singleton,
True_._singleton,
initial_clause,
*clauses,
)
@property
def _select_iterable(self) -> _SelectIterable:
return (self,)
def self_group(self, against=None):
if not self.clauses:
return self
else:
return super().self_group(against=against)
and_ = BooleanClauseList.and_
or_ = BooleanClauseList.or_
class Tuple(ClauseList, ColumnElement[typing_Tuple[Any, ...]]):
"""Represent a SQL tuple."""
__visit_name__ = "tuple"
_traverse_internals: _TraverseInternalsType = (
ClauseList._traverse_internals + []
)
type: TupleType
@util.preload_module("sqlalchemy.sql.sqltypes")
def __init__(
self,
*clauses: _ColumnExpressionArgument[Any],
types: Optional[Sequence[_TypeEngineArgument[Any]]] = None,
):
sqltypes = util.preloaded.sql_sqltypes
if types is None:
init_clauses: List[ColumnElement[Any]] = [
coercions.expect(roles.ExpressionElementRole, c)
for c in clauses
]
else:
if len(types) != len(clauses):
raise exc.ArgumentError(
"Wrong number of elements for %d-tuple: %r "
% (len(types), clauses)
)
init_clauses = [
coercions.expect(
roles.ExpressionElementRole,
c,
type_=typ if not typ._isnull else None,
)
for typ, c in zip(types, clauses)
]
self.type = sqltypes.TupleType(*[arg.type for arg in init_clauses])
super().__init__(*init_clauses)
@property
def _select_iterable(self) -> _SelectIterable:
return (self,)
def _bind_param(self, operator, obj, type_=None, expanding=False):
if expanding:
return BindParameter(
None,
value=obj,
_compared_to_operator=operator,
unique=True,
expanding=True,
type_=type_,
_compared_to_type=self.type,
)
else:
return Tuple(
*[
BindParameter(
None,
o,
_compared_to_operator=operator,
_compared_to_type=compared_to_type,
unique=True,
type_=type_,
)
for o, compared_to_type in zip(obj, self.type.types)
]
)
def self_group(self, against=None):
# Tuple is parenthesized by definition.
return self
class Case(ColumnElement[_T]):
"""Represent a ``CASE`` expression.
:class:`.Case` is produced using the :func:`.case` factory function,
as in::
from sqlalchemy import case
stmt = select(users_table).\
where(
case(
(users_table.c.name == 'wendy', 'W'),
(users_table.c.name == 'jack', 'J'),
else_='E'
)
)
Details on :class:`.Case` usage is at :func:`.case`.
.. seealso::
:func:`.case`
"""
__visit_name__ = "case"
_traverse_internals: _TraverseInternalsType = [
("value", InternalTraversal.dp_clauseelement),
("whens", InternalTraversal.dp_clauseelement_tuples),
("else_", InternalTraversal.dp_clauseelement),
]
# for case(), the type is derived from the whens. so for the moment
# users would have to cast() the case to get a specific type
whens: List[typing_Tuple[ColumnElement[bool], ColumnElement[_T]]]
else_: Optional[ColumnElement[_T]]
value: Optional[ColumnElement[Any]]
def __init__(
self,
*whens: Union[
typing_Tuple[_ColumnExpressionArgument[bool], Any],
Mapping[Any, Any],
],
value: Optional[Any] = None,
else_: Optional[Any] = None,
):
new_whens: Iterable[Any] = coercions._expression_collection_was_a_list(
"whens", "case", whens
)
try:
new_whens = util.dictlike_iteritems(new_whens)
except TypeError:
pass
whenlist = [
(
coercions.expect(
roles.ExpressionElementRole,
c,
apply_propagate_attrs=self,
).self_group(),
coercions.expect(roles.ExpressionElementRole, r),
)
for (c, r) in new_whens
]
if whenlist:
type_ = whenlist[-1][-1].type
else:
type_ = None
if value is None:
self.value = None
else:
self.value = coercions.expect(roles.ExpressionElementRole, value)
self.type = cast(_T, type_)
self.whens = whenlist
if else_ is not None:
self.else_ = coercions.expect(roles.ExpressionElementRole, else_)
else:
self.else_ = None
@util.ro_non_memoized_property
def _from_objects(self) -> List[FromClause]:
return list(
itertools.chain(*[x._from_objects for x in self.get_children()])
)
class Cast(WrapsColumnExpression[_T]):
"""Represent a ``CAST`` expression.
:class:`.Cast` is produced using the :func:`.cast` factory function,
as in::
from sqlalchemy import cast, Numeric
stmt = select(cast(product_table.c.unit_price, Numeric(10, 4)))
Details on :class:`.Cast` usage is at :func:`.cast`.
.. seealso::
:ref:`tutorial_casts`
:func:`.cast`
:func:`.type_coerce` - an alternative to CAST that coerces the type
on the Python side only, which is often sufficient to generate the
correct SQL and data coercion.
"""
__visit_name__ = "cast"
_traverse_internals: _TraverseInternalsType = [
("clause", InternalTraversal.dp_clauseelement),
("type", InternalTraversal.dp_type),
]
clause: ColumnElement[Any]
type: TypeEngine[_T]
typeclause: TypeClause
def __init__(
self,
expression: _ColumnExpressionArgument[Any],
type_: _TypeEngineArgument[_T],
):
self.type = type_api.to_instance(type_)
self.clause = coercions.expect(
roles.ExpressionElementRole,
expression,
type_=self.type,
apply_propagate_attrs=self,
)
self.typeclause = TypeClause(self.type)
@util.ro_non_memoized_property
def _from_objects(self) -> List[FromClause]:
return self.clause._from_objects
@property
def wrapped_column_expression(self):
return self.clause
class TypeCoerce(WrapsColumnExpression[_T]):
"""Represent a Python-side type-coercion wrapper.
:class:`.TypeCoerce` supplies the :func:`_expression.type_coerce`
function; see that function for usage details.
.. versionchanged:: 1.1 The :func:`.type_coerce` function now produces
a persistent :class:`.TypeCoerce` wrapper object rather than
translating the given object in place.
.. seealso::
:func:`_expression.type_coerce`
:func:`.cast`
"""
__visit_name__ = "type_coerce"
_traverse_internals: _TraverseInternalsType = [
("clause", InternalTraversal.dp_clauseelement),
("type", InternalTraversal.dp_type),
]
clause: ColumnElement[Any]
type: TypeEngine[_T]
def __init__(
self,
expression: _ColumnExpressionArgument[Any],
type_: _TypeEngineArgument[_T],
):
self.type = type_api.to_instance(type_)
self.clause = coercions.expect(
roles.ExpressionElementRole,
expression,
type_=self.type,
apply_propagate_attrs=self,
)
@util.ro_non_memoized_property
def _from_objects(self) -> List[FromClause]:
return self.clause._from_objects
@HasMemoized.memoized_attribute
def typed_expression(self):
if isinstance(self.clause, BindParameter):
bp = self.clause._clone()
bp.type = self.type
return bp
else:
return self.clause
@property
def wrapped_column_expression(self):
return self.clause
def self_group(self, against=None):
grouped = self.clause.self_group(against=against)
if grouped is not self.clause:
return TypeCoerce(grouped, self.type)
else:
return self
class Extract(ColumnElement[int]):
"""Represent a SQL EXTRACT clause, ``extract(field FROM expr)``."""
__visit_name__ = "extract"
_traverse_internals: _TraverseInternalsType = [
("expr", InternalTraversal.dp_clauseelement),
("field", InternalTraversal.dp_string),
]
expr: ColumnElement[Any]
field: str
def __init__(self, field: str, expr: _ColumnExpressionArgument[Any]):
self.type = type_api.INTEGERTYPE
self.field = field
self.expr = coercions.expect(roles.ExpressionElementRole, expr)
@util.ro_non_memoized_property
def _from_objects(self) -> List[FromClause]:
return self.expr._from_objects
class _label_reference(ColumnElement[_T]):
"""Wrap a column expression as it appears in a 'reference' context.
This expression is any that includes an _order_by_label_element,
which is a Label, or a DESC / ASC construct wrapping a Label.
The production of _label_reference() should occur when an expression
is added to this context; this includes the ORDER BY or GROUP BY of a
SELECT statement, as well as a few other places, such as the ORDER BY
within an OVER clause.
"""
__visit_name__ = "label_reference"
_traverse_internals: _TraverseInternalsType = [
("element", InternalTraversal.dp_clauseelement)
]
element: ColumnElement[_T]
def __init__(self, element: ColumnElement[_T]):
self.element = element
@util.ro_non_memoized_property
def _from_objects(self) -> List[FromClause]:
return []
class _textual_label_reference(ColumnElement[Any]):
__visit_name__ = "textual_label_reference"
_traverse_internals: _TraverseInternalsType = [
("element", InternalTraversal.dp_string)
]
def __init__(self, element: str):
self.element = element
@util.memoized_property
def _text_clause(self) -> TextClause:
return TextClause(self.element)
class UnaryExpression(ColumnElement[_T]):
"""Define a 'unary' expression.
A unary expression has a single column expression
and an operator. The operator can be placed on the left
(where it is called the 'operator') or right (where it is called the
'modifier') of the column expression.
:class:`.UnaryExpression` is the basis for several unary operators
including those used by :func:`.desc`, :func:`.asc`, :func:`.distinct`,
:func:`.nulls_first` and :func:`.nulls_last`.
"""
__visit_name__ = "unary"
_traverse_internals: _TraverseInternalsType = [
("element", InternalTraversal.dp_clauseelement),
("operator", InternalTraversal.dp_operator),
("modifier", InternalTraversal.dp_operator),
]
element: ClauseElement
def __init__(
self,
element: ColumnElement[Any],
operator: Optional[OperatorType] = None,
modifier: Optional[OperatorType] = None,
type_: Optional[_TypeEngineArgument[_T]] = None,
wraps_column_expression: bool = False,
):
self.operator = operator
self.modifier = modifier
self._propagate_attrs = element._propagate_attrs
self.element = element.self_group(
against=self.operator or self.modifier
)
# if type is None, we get NULLTYPE, which is our _T. But I don't
# know how to get the overloads to express that correctly
self.type = type_api.to_instance(type_) # type: ignore
self.wraps_column_expression = wraps_column_expression
@classmethod
def _create_nulls_first(
cls,
column: _ColumnExpressionArgument[_T],
) -> UnaryExpression[_T]:
return UnaryExpression(
coercions.expect(roles.ByOfRole, column),
modifier=operators.nulls_first_op,
wraps_column_expression=False,
)
@classmethod
def _create_nulls_last(
cls,
column: _ColumnExpressionArgument[_T],
) -> UnaryExpression[_T]:
return UnaryExpression(
coercions.expect(roles.ByOfRole, column),
modifier=operators.nulls_last_op,
wraps_column_expression=False,
)
@classmethod
def _create_desc(
cls, column: _ColumnExpressionOrStrLabelArgument[_T]
) -> UnaryExpression[_T]:
return UnaryExpression(
coercions.expect(roles.ByOfRole, column),
modifier=operators.desc_op,
wraps_column_expression=False,
)
@classmethod
def _create_asc(
cls,
column: _ColumnExpressionOrStrLabelArgument[_T],
) -> UnaryExpression[_T]:
return UnaryExpression(
coercions.expect(roles.ByOfRole, column),
modifier=operators.asc_op,
wraps_column_expression=False,
)
@classmethod
def _create_distinct(
cls,
expr: _ColumnExpressionArgument[_T],
) -> UnaryExpression[_T]:
col_expr: ColumnElement[_T] = coercions.expect(
roles.ExpressionElementRole, expr
)
return UnaryExpression(
col_expr,
operator=operators.distinct_op,
type_=col_expr.type,
wraps_column_expression=False,
)
@classmethod
def _create_bitwise_not(
cls,
expr: _ColumnExpressionArgument[_T],
) -> UnaryExpression[_T]:
col_expr: ColumnElement[_T] = coercions.expect(
roles.ExpressionElementRole, expr
)
return UnaryExpression(
col_expr,
operator=operators.bitwise_not_op,
type_=col_expr.type,
wraps_column_expression=False,
)
@property
def _order_by_label_element(self) -> Optional[Label[Any]]:
if self.modifier in (operators.desc_op, operators.asc_op):
return self.element._order_by_label_element
else:
return None
@util.ro_non_memoized_property
def _from_objects(self) -> List[FromClause]:
return self.element._from_objects
def _negate(self):
if self.type._type_affinity is type_api.BOOLEANTYPE._type_affinity:
return UnaryExpression(
self.self_group(against=operators.inv),
operator=operators.inv,
type_=type_api.BOOLEANTYPE,
wraps_column_expression=self.wraps_column_expression,
)
else:
return ClauseElement._negate(self)
def self_group(self, against=None):
if self.operator and operators.is_precedent(self.operator, against):
return Grouping(self)
else:
return self
class CollectionAggregate(UnaryExpression[_T]):
"""Forms the basis for right-hand collection operator modifiers
ANY and ALL.
The ANY and ALL keywords are available in different ways on different
backends. On PostgreSQL, they only work for an ARRAY type. On
MySQL, they only work for subqueries.
"""
inherit_cache = True
@classmethod
def _create_any(
cls, expr: _ColumnExpressionArgument[_T]
) -> CollectionAggregate[bool]:
col_expr: ColumnElement[_T] = coercions.expect(
roles.ExpressionElementRole,
expr,
)
col_expr = col_expr.self_group()
return CollectionAggregate(
col_expr,
operator=operators.any_op,
type_=type_api.BOOLEANTYPE,
wraps_column_expression=False,
)
@classmethod
def _create_all(
cls, expr: _ColumnExpressionArgument[_T]
) -> CollectionAggregate[bool]:
col_expr: ColumnElement[_T] = coercions.expect(
roles.ExpressionElementRole,
expr,
)
col_expr = col_expr.self_group()
return CollectionAggregate(
col_expr,
operator=operators.all_op,
type_=type_api.BOOLEANTYPE,
wraps_column_expression=False,
)
# operate and reverse_operate are hardwired to
# dispatch onto the type comparator directly, so that we can
# ensure "reversed" behavior.
def operate(self, op, *other, **kwargs):
if not operators.is_comparison(op):
raise exc.ArgumentError(
"Only comparison operators may be used with ANY/ALL"
)
kwargs["reverse"] = kwargs["_any_all_expr"] = True
return self.comparator.operate(operators.mirror(op), *other, **kwargs)
def reverse_operate(self, op, other, **kwargs):
# comparison operators should never call reverse_operate
assert not operators.is_comparison(op)
raise exc.ArgumentError(
"Only comparison operators may be used with ANY/ALL"
)
class AsBoolean(WrapsColumnExpression[bool], UnaryExpression[bool]):
inherit_cache = True
def __init__(self, element, operator, negate):
self.element = element
self.type = type_api.BOOLEANTYPE
self.operator = operator
self.negate = negate
self.modifier = None
self.wraps_column_expression = True
self._is_implicitly_boolean = element._is_implicitly_boolean
@property
def wrapped_column_expression(self):
return self.element
def self_group(self, against=None):
return self
def _negate(self):
if isinstance(self.element, (True_, False_)):
return self.element._negate()
else:
return AsBoolean(self.element, self.negate, self.operator)
class BinaryExpression(OperatorExpression[_T]):
"""Represent an expression that is ``LEFT <operator> RIGHT``.
A :class:`.BinaryExpression` is generated automatically
whenever two column expressions are used in a Python binary expression:
.. sourcecode:: pycon+sql
>>> from sqlalchemy.sql import column
>>> column('a') + column('b')
<sqlalchemy.sql.expression.BinaryExpression object at 0x101029dd0>
>>> print(column('a') + column('b'))
{printsql}a + b
"""
__visit_name__ = "binary"
_traverse_internals: _TraverseInternalsType = [
("left", InternalTraversal.dp_clauseelement),
("right", InternalTraversal.dp_clauseelement),
("operator", InternalTraversal.dp_operator),
("negate", InternalTraversal.dp_operator),
("modifiers", InternalTraversal.dp_plain_dict),
(
"type",
InternalTraversal.dp_type,
),
]
_cache_key_traversal = [
("left", InternalTraversal.dp_clauseelement),
("right", InternalTraversal.dp_clauseelement),
("operator", InternalTraversal.dp_operator),
("modifiers", InternalTraversal.dp_plain_dict),
# "type" affects JSON CAST operators, so while redundant in most cases,
# is needed for that one
(
"type",
InternalTraversal.dp_type,
),
]
_is_implicitly_boolean = True
"""Indicates that any database will know this is a boolean expression
even if the database does not have an explicit boolean datatype.
"""
modifiers: Optional[Mapping[str, Any]]
left: ColumnElement[Any]
right: ColumnElement[Any]
def __init__(
self,
left: ColumnElement[Any],
right: ColumnElement[Any],
operator: OperatorType,
type_: Optional[_TypeEngineArgument[_T]] = None,
negate: Optional[OperatorType] = None,
modifiers: Optional[Mapping[str, Any]] = None,
):
# allow compatibility with libraries that
# refer to BinaryExpression directly and pass strings
if isinstance(operator, str):
operator = operators.custom_op(operator)
self._orig = (left.__hash__(), right.__hash__())
self._propagate_attrs = left._propagate_attrs or right._propagate_attrs
self.left = left.self_group(against=operator)
self.right = right.self_group(against=operator)
self.operator = operator
# if type is None, we get NULLTYPE, which is our _T. But I don't
# know how to get the overloads to express that correctly
self.type = type_api.to_instance(type_) # type: ignore
self.negate = negate
self._is_implicitly_boolean = operators.is_boolean(operator)
if modifiers is None:
self.modifiers = {}
else:
self.modifiers = modifiers
@property
def _flattened_operator_clauses(
self,
) -> typing_Tuple[ColumnElement[Any], ...]:
return (self.left, self.right)
def __bool__(self):
"""Implement Python-side "bool" for BinaryExpression as a
simple "identity" check for the left and right attributes,
if the operator is "eq" or "ne". Otherwise the expression
continues to not support "bool" like all other column expressions.
The rationale here is so that ColumnElement objects can be hashable.
What? Well, suppose you do this::
c1, c2 = column('x'), column('y')
s1 = set([c1, c2])
We do that **a lot**, columns inside of sets is an extremely basic
thing all over the ORM for example.
So what happens if we do this? ::
c1 in s1
Hashing means it will normally use ``__hash__()`` of the object,
but in case of hash collision, it's going to also do ``c1 == c1``
and/or ``c1 == c2`` inside. Those operations need to return a
True/False value. But because we override ``==`` and ``!=``, they're
going to get a BinaryExpression. Hence we implement ``__bool__`` here
so that these comparisons behave in this particular context mostly
like regular object comparisons. Thankfully Python is OK with
that! Otherwise we'd have to use special set classes for columns
(which we used to do, decades ago).
"""
if self.operator in (operators.eq, operators.ne):
# this is using the eq/ne operator given int hash values,
# rather than Operator, so that "bool" can be based on
# identity
return self.operator(*self._orig) # type: ignore
else:
raise TypeError("Boolean value of this clause is not defined")
if typing.TYPE_CHECKING:
def __invert__(
self: BinaryExpression[_T],
) -> BinaryExpression[_T]:
...
@util.ro_non_memoized_property
def _from_objects(self) -> List[FromClause]:
return self.left._from_objects + self.right._from_objects
def _negate(self):
if self.negate is not None:
return BinaryExpression(
self.left,
self.right._negate_in_binary(self.negate, self.operator),
self.negate,
negate=self.operator,
type_=self.type,
modifiers=self.modifiers,
)
else:
return super()._negate()
class Slice(ColumnElement[Any]):
"""Represent SQL for a Python array-slice object.
This is not a specific SQL construct at this level, but
may be interpreted by specific dialects, e.g. PostgreSQL.
"""
__visit_name__ = "slice"
_traverse_internals: _TraverseInternalsType = [
("start", InternalTraversal.dp_clauseelement),
("stop", InternalTraversal.dp_clauseelement),
("step", InternalTraversal.dp_clauseelement),
]
def __init__(self, start, stop, step, _name=None):
self.start = coercions.expect(
roles.ExpressionElementRole,
start,
name=_name,
type_=type_api.INTEGERTYPE,
)
self.stop = coercions.expect(
roles.ExpressionElementRole,
stop,
name=_name,
type_=type_api.INTEGERTYPE,
)
self.step = coercions.expect(
roles.ExpressionElementRole,
step,
name=_name,
type_=type_api.INTEGERTYPE,
)
self.type = type_api.NULLTYPE
def self_group(self, against=None):
assert against is operator.getitem
return self
class IndexExpression(BinaryExpression[Any]):
"""Represent the class of expressions that are like an "index"
operation."""
inherit_cache = True
class GroupedElement(DQLDMLClauseElement):
"""Represent any parenthesized expression"""
__visit_name__ = "grouping"
element: ClauseElement
def self_group(self, against=None):
return self
def _ungroup(self):
return self.element._ungroup()
class Grouping(GroupedElement, ColumnElement[_T]):
"""Represent a grouping within a column expression"""
_traverse_internals: _TraverseInternalsType = [
("element", InternalTraversal.dp_clauseelement),
("type", InternalTraversal.dp_type),
]
_cache_key_traversal = [
("element", InternalTraversal.dp_clauseelement),
]
element: Union[TextClause, ClauseList, ColumnElement[_T]]
def __init__(
self, element: Union[TextClause, ClauseList, ColumnElement[_T]]
):
self.element = element
# nulltype assignment issue
self.type = getattr(element, "type", type_api.NULLTYPE) # type: ignore
def _with_binary_element_type(self, type_):
return self.__class__(self.element._with_binary_element_type(type_))
@util.memoized_property
def _is_implicitly_boolean(self):
return self.element._is_implicitly_boolean
@util.non_memoized_property
def _tq_label(self) -> Optional[str]:
return (
getattr(self.element, "_tq_label", None) or self._anon_name_label
)
@util.non_memoized_property
def _proxies(self) -> List[ColumnElement[Any]]:
if isinstance(self.element, ColumnElement):
return [self.element]
else:
return []
@util.ro_non_memoized_property
def _from_objects(self) -> List[FromClause]:
return self.element._from_objects
def __getattr__(self, attr):
return getattr(self.element, attr)
def __getstate__(self):
return {"element": self.element, "type": self.type}
def __setstate__(self, state):
self.element = state["element"]
self.type = state["type"]
class _OverRange(IntEnum):
RANGE_UNBOUNDED = 0
RANGE_CURRENT = 1
RANGE_UNBOUNDED = _OverRange.RANGE_UNBOUNDED
RANGE_CURRENT = _OverRange.RANGE_CURRENT
class Over(ColumnElement[_T]):
"""Represent an OVER clause.
This is a special operator against a so-called
"window" function, as well as any aggregate function,
which produces results relative to the result set
itself. Most modern SQL backends now support window functions.
"""
__visit_name__ = "over"
_traverse_internals: _TraverseInternalsType = [
("element", InternalTraversal.dp_clauseelement),
("order_by", InternalTraversal.dp_clauseelement),
("partition_by", InternalTraversal.dp_clauseelement),
("range_", InternalTraversal.dp_plain_obj),
("rows", InternalTraversal.dp_plain_obj),
]
order_by: Optional[ClauseList] = None
partition_by: Optional[ClauseList] = None
element: ColumnElement[_T]
"""The underlying expression object to which this :class:`.Over`
object refers towards."""
range_: Optional[typing_Tuple[int, int]]
def __init__(
self,
element: ColumnElement[_T],
partition_by: Optional[
Union[
Iterable[_ColumnExpressionArgument[Any]],
_ColumnExpressionArgument[Any],
]
] = None,
order_by: Optional[
Union[
Iterable[_ColumnExpressionArgument[Any]],
_ColumnExpressionArgument[Any],
]
] = None,
range_: Optional[typing_Tuple[Optional[int], Optional[int]]] = None,
rows: Optional[typing_Tuple[Optional[int], Optional[int]]] = None,
):
self.element = element
if order_by is not None:
self.order_by = ClauseList(
*util.to_list(order_by), _literal_as_text_role=roles.ByOfRole
)
if partition_by is not None:
self.partition_by = ClauseList(
*util.to_list(partition_by),
_literal_as_text_role=roles.ByOfRole,
)
if range_:
self.range_ = self._interpret_range(range_)
if rows:
raise exc.ArgumentError(
"'range_' and 'rows' are mutually exclusive"
)
else:
self.rows = None
elif rows:
self.rows = self._interpret_range(rows)
self.range_ = None
else:
self.rows = self.range_ = None
def __reduce__(self):
return self.__class__, (
self.element,
self.partition_by,
self.order_by,
self.range_,
self.rows,
)
def _interpret_range(
self, range_: typing_Tuple[Optional[int], Optional[int]]
) -> typing_Tuple[int, int]:
if not isinstance(range_, tuple) or len(range_) != 2:
raise exc.ArgumentError("2-tuple expected for range/rows")
lower: int
upper: int
if range_[0] is None:
lower = RANGE_UNBOUNDED
else:
try:
lower = int(range_[0])
except ValueError as err:
raise exc.ArgumentError(
"Integer or None expected for range value"
) from err
else:
if lower == 0:
lower = RANGE_CURRENT
if range_[1] is None:
upper = RANGE_UNBOUNDED
else:
try:
upper = int(range_[1])
except ValueError as err:
raise exc.ArgumentError(
"Integer or None expected for range value"
) from err
else:
if upper == 0:
upper = RANGE_CURRENT
return lower, upper
@util.memoized_property
def type(self):
return self.element.type
@util.ro_non_memoized_property
def _from_objects(self) -> List[FromClause]:
return list(
itertools.chain(
*[
c._from_objects
for c in (self.element, self.partition_by, self.order_by)
if c is not None
]
)
)
class WithinGroup(ColumnElement[_T]):
"""Represent a WITHIN GROUP (ORDER BY) clause.
This is a special operator against so-called
"ordered set aggregate" and "hypothetical
set aggregate" functions, including ``percentile_cont()``,
``rank()``, ``dense_rank()``, etc.
It's supported only by certain database backends, such as PostgreSQL,
Oracle and MS SQL Server.
The :class:`.WithinGroup` construct extracts its type from the
method :meth:`.FunctionElement.within_group_type`. If this returns
``None``, the function's ``.type`` is used.
"""
__visit_name__ = "withingroup"
_traverse_internals: _TraverseInternalsType = [
("element", InternalTraversal.dp_clauseelement),
("order_by", InternalTraversal.dp_clauseelement),
]
order_by: Optional[ClauseList] = None
def __init__(
self,
element: FunctionElement[_T],
*order_by: _ColumnExpressionArgument[Any],
):
self.element = element
if order_by is not None:
self.order_by = ClauseList(
*util.to_list(order_by), _literal_as_text_role=roles.ByOfRole
)
def __reduce__(self):
return self.__class__, (self.element,) + (
tuple(self.order_by) if self.order_by is not None else ()
)
def over(self, partition_by=None, order_by=None, range_=None, rows=None):
"""Produce an OVER clause against this :class:`.WithinGroup`
construct.
This function has the same signature as that of
:meth:`.FunctionElement.over`.
"""
return Over(
self,
partition_by=partition_by,
order_by=order_by,
range_=range_,
rows=rows,
)
@util.memoized_property
def type(self):
wgt = self.element.within_group_type(self)
if wgt is not None:
return wgt
else:
return self.element.type
@util.ro_non_memoized_property
def _from_objects(self) -> List[FromClause]:
return list(
itertools.chain(
*[
c._from_objects
for c in (self.element, self.order_by)
if c is not None
]
)
)
class FunctionFilter(ColumnElement[_T]):
"""Represent a function FILTER clause.
This is a special operator against aggregate and window functions,
which controls which rows are passed to it.
It's supported only by certain database backends.
Invocation of :class:`.FunctionFilter` is via
:meth:`.FunctionElement.filter`::
func.count(1).filter(True)
.. versionadded:: 1.0.0
.. seealso::
:meth:`.FunctionElement.filter`
"""
__visit_name__ = "funcfilter"
_traverse_internals: _TraverseInternalsType = [
("func", InternalTraversal.dp_clauseelement),
("criterion", InternalTraversal.dp_clauseelement),
]
criterion: Optional[ColumnElement[bool]] = None
def __init__(
self,
func: FunctionElement[_T],
*criterion: _ColumnExpressionArgument[bool],
):
self.func = func
self.filter(*criterion)
def filter(self, *criterion):
"""Produce an additional FILTER against the function.
This method adds additional criteria to the initial criteria
set up by :meth:`.FunctionElement.filter`.
Multiple criteria are joined together at SQL render time
via ``AND``.
"""
for crit in list(criterion):
crit = coercions.expect(roles.WhereHavingRole, crit)
if self.criterion is not None:
self.criterion = self.criterion & crit
else:
self.criterion = crit
return self
def over(
self,
partition_by: Optional[
Union[
Iterable[_ColumnExpressionArgument[Any]],
_ColumnExpressionArgument[Any],
]
] = None,
order_by: Optional[
Union[
Iterable[_ColumnExpressionArgument[Any]],
_ColumnExpressionArgument[Any],
]
] = None,
range_: Optional[typing_Tuple[Optional[int], Optional[int]]] = None,
rows: Optional[typing_Tuple[Optional[int], Optional[int]]] = None,
) -> Over[_T]:
"""Produce an OVER clause against this filtered function.
Used against aggregate or so-called "window" functions,
for database backends that support window functions.
The expression::
func.rank().filter(MyClass.y > 5).over(order_by='x')
is shorthand for::
from sqlalchemy import over, funcfilter
over(funcfilter(func.rank(), MyClass.y > 5), order_by='x')
See :func:`_expression.over` for a full description.
"""
return Over(
self,
partition_by=partition_by,
order_by=order_by,
range_=range_,
rows=rows,
)
def self_group(self, against=None):
if operators.is_precedent(operators.filter_op, against):
return Grouping(self)
else:
return self
@util.memoized_property
def type(self):
return self.func.type
@util.ro_non_memoized_property
def _from_objects(self) -> List[FromClause]:
return list(
itertools.chain(
*[
c._from_objects
for c in (self.func, self.criterion)
if c is not None
]
)
)
class NamedColumn(KeyedColumnElement[_T]):
is_literal = False
table: Optional[FromClause] = None
name: str
key: str
def _compare_name_for_result(self, other):
return (hasattr(other, "name") and self.name == other.name) or (
hasattr(other, "_label") and self._label == other._label
)
@util.ro_memoized_property
def description(self) -> str:
return self.name
@HasMemoized.memoized_attribute
def _tq_key_label(self):
"""table qualified label based on column key.
for table-bound columns this is <tablename>_<column key/proxy key>;
all other expressions it resolves to key/proxy key.
"""
proxy_key = self._proxy_key
if proxy_key and proxy_key != self.name:
return self._gen_tq_label(proxy_key)
else:
return self._tq_label
@HasMemoized.memoized_attribute
def _tq_label(self) -> Optional[str]:
"""table qualified label based on column name.
for table-bound columns this is <tablename>_<columnname>; all other
expressions it resolves to .name.
"""
return self._gen_tq_label(self.name)
@HasMemoized.memoized_attribute
def _render_label_in_columns_clause(self):
return True
@HasMemoized.memoized_attribute
def _non_anon_label(self):
return self.name
def _gen_tq_label(
self, name: str, dedupe_on_key: bool = True
) -> Optional[str]:
return name
def _bind_param(
self,
operator: OperatorType,
obj: Any,
type_: Optional[TypeEngine[_T]] = None,
expanding: bool = False,
) -> BindParameter[_T]:
return BindParameter(
self.key,
obj,
_compared_to_operator=operator,
_compared_to_type=self.type,
type_=type_,
unique=True,
expanding=expanding,
)
def _make_proxy(
self,
selectable: FromClause,
*,
name: Optional[str] = None,
key: Optional[str] = None,
name_is_truncatable: bool = False,
compound_select_cols: Optional[Sequence[ColumnElement[Any]]] = None,
disallow_is_literal: bool = False,
**kw: Any,
) -> typing_Tuple[str, ColumnClause[_T]]:
c = ColumnClause(
coercions.expect(roles.TruncatedLabelRole, name or self.name)
if name_is_truncatable
else (name or self.name),
type_=self.type,
_selectable=selectable,
is_literal=False,
)
c._propagate_attrs = selectable._propagate_attrs
if name is None:
c.key = self.key
if compound_select_cols:
c._proxies = list(compound_select_cols)
else:
c._proxies = [self]
if selectable._is_clone_of is not None:
c._is_clone_of = selectable._is_clone_of.columns.get(c.key)
return c.key, c
class Label(roles.LabeledColumnExprRole[_T], NamedColumn[_T]):
"""Represents a column label (AS).
Represent a label, as typically applied to any column-level
element using the ``AS`` sql keyword.
"""
__visit_name__ = "label"
_traverse_internals: _TraverseInternalsType = [
("name", InternalTraversal.dp_anon_name),
("type", InternalTraversal.dp_type),
("_element", InternalTraversal.dp_clauseelement),
]
_cache_key_traversal = [
("name", InternalTraversal.dp_anon_name),
("_element", InternalTraversal.dp_clauseelement),
]
_element: ColumnElement[_T]
name: str
def __init__(
self,
name: Optional[str],
element: _ColumnExpressionArgument[_T],
type_: Optional[_TypeEngineArgument[_T]] = None,
):
orig_element = element
element = coercions.expect(
roles.ExpressionElementRole,
element,
apply_propagate_attrs=self,
)
while isinstance(element, Label):
# TODO: this is only covered in test_text.py, but nothing
# fails if it's removed. determine rationale
element = element.element
if name:
self.name = name
else:
self.name = _anonymous_label.safe_construct(
id(self), getattr(element, "name", "anon")
)
if isinstance(orig_element, Label):
# TODO: no coverage for this block, again would be in
# test_text.py where the resolve_label concept is important
self._resolve_label = orig_element._label
self.key = self._tq_label = self._tq_key_label = self.name
self._element = element
self.type = (
type_api.to_instance(type_)
if type_ is not None
else self._element.type
)
self._proxies = [element]
def __reduce__(self):
return self.__class__, (self.name, self._element, self.type)
@HasMemoized.memoized_attribute
def _render_label_in_columns_clause(self):
return True
def _bind_param(self, operator, obj, type_=None, expanding=False):
return BindParameter(
None,
obj,
_compared_to_operator=operator,
type_=type_,
_compared_to_type=self.type,
unique=True,
expanding=expanding,
)
@util.memoized_property
def _is_implicitly_boolean(self):
return self.element._is_implicitly_boolean
@HasMemoized.memoized_attribute
def _allow_label_resolve(self):
return self.element._allow_label_resolve
@property
def _order_by_label_element(self):
return self
@HasMemoized.memoized_attribute
def element(self) -> ColumnElement[_T]:
return self._element.self_group(against=operators.as_)
def self_group(self, against=None):
return self._apply_to_inner(self._element.self_group, against=against)
def _negate(self):
return self._apply_to_inner(self._element._negate)
def _apply_to_inner(self, fn, *arg, **kw):
sub_element = fn(*arg, **kw)
if sub_element is not self._element:
return Label(self.name, sub_element, type_=self.type)
else:
return self
@property
def primary_key(self):
return self.element.primary_key
@property
def foreign_keys(self):
return self.element.foreign_keys
def _copy_internals(
self,
*,
clone: _CloneCallableType = _clone,
anonymize_labels: bool = False,
**kw: Any,
) -> None:
self._reset_memoizations()
self._element = clone(self._element, **kw)
if anonymize_labels:
self.name = _anonymous_label.safe_construct(
id(self), getattr(self.element, "name", "anon")
)
self.key = self._tq_label = self._tq_key_label = self.name
@util.ro_non_memoized_property
def _from_objects(self) -> List[FromClause]:
return self.element._from_objects
def _make_proxy(
self,
selectable: FromClause,
*,
name: Optional[str] = None,
compound_select_cols: Optional[Sequence[ColumnElement[Any]]] = None,
**kw: Any,
) -> typing_Tuple[str, ColumnClause[_T]]:
name = self.name if not name else name
key, e = self.element._make_proxy(
selectable,
name=name,
disallow_is_literal=True,
name_is_truncatable=isinstance(name, _truncated_label),
compound_select_cols=compound_select_cols,
)
# there was a note here to remove this assertion, which was here
# to determine if we later could support a use case where
# the key and name of a label are separate. But I don't know what
# that case was. For now, this is an unexpected case that occurs
# when a label name conflicts with other columns and select()
# is attempting to disambiguate an explicit label, which is not what
# the user would want. See issue #6090.
if key != self.name and not isinstance(self.name, _anonymous_label):
raise exc.InvalidRequestError(
"Label name %s is being renamed to an anonymous label due "
"to disambiguation "
"which is not supported right now. Please use unique names "
"for explicit labels." % (self.name)
)
e._propagate_attrs = selectable._propagate_attrs
e._proxies.append(self)
if self.type is not None:
e.type = self.type
return self.key, e
class ColumnClause(
roles.DDLReferredColumnRole,
roles.LabeledColumnExprRole[_T],
roles.StrAsPlainColumnRole,
Immutable,
NamedColumn[_T],
):
"""Represents a column expression from any textual string.
The :class:`.ColumnClause`, a lightweight analogue to the
:class:`_schema.Column` class, is typically invoked using the
:func:`_expression.column` function, as in::
from sqlalchemy import column
id, name = column("id"), column("name")
stmt = select(id, name).select_from("user")
The above statement would produce SQL like::
SELECT id, name FROM user
:class:`.ColumnClause` is the immediate superclass of the schema-specific
:class:`_schema.Column` object. While the :class:`_schema.Column`
class has all the
same capabilities as :class:`.ColumnClause`, the :class:`.ColumnClause`
class is usable by itself in those cases where behavioral requirements
are limited to simple SQL expression generation. The object has none of
the associations with schema-level metadata or with execution-time
behavior that :class:`_schema.Column` does,
so in that sense is a "lightweight"
version of :class:`_schema.Column`.
Full details on :class:`.ColumnClause` usage is at
:func:`_expression.column`.
.. seealso::
:func:`_expression.column`
:class:`_schema.Column`
"""
table: Optional[FromClause]
is_literal: bool
__visit_name__ = "column"
_traverse_internals: _TraverseInternalsType = [
("name", InternalTraversal.dp_anon_name),
("type", InternalTraversal.dp_type),
("table", InternalTraversal.dp_clauseelement),
("is_literal", InternalTraversal.dp_boolean),
]
onupdate: Optional[DefaultGenerator] = None
default: Optional[DefaultGenerator] = None
server_default: Optional[_ServerDefaultType] = None
server_onupdate: Optional[FetchedValue] = None
_is_multiparam_column = False
@property
def _is_star(self):
return self.is_literal and self.name == "*"
def __init__(
self,
text: str,
type_: Optional[_TypeEngineArgument[_T]] = None,
is_literal: bool = False,
_selectable: Optional[FromClause] = None,
):
self.key = self.name = text
self.table = _selectable
# if type is None, we get NULLTYPE, which is our _T. But I don't
# know how to get the overloads to express that correctly
self.type = type_api.to_instance(type_) # type: ignore
self.is_literal = is_literal
def get_children(self, *, column_tables=False, **kw):
# override base get_children() to not return the Table
# or selectable that is parent to this column. Traversals
# expect the columns of tables and subqueries to be leaf nodes.
return []
@property
def entity_namespace(self):
if self.table is not None:
return self.table.entity_namespace
else:
return super().entity_namespace
def _clone(self, detect_subquery_cols=False, **kw):
if (
detect_subquery_cols
and self.table is not None
and self.table._is_subquery
):
clone = kw.pop("clone")
table = clone(self.table, **kw)
new = table.c.corresponding_column(self)
return new
return super()._clone(**kw)
@HasMemoized_ro_memoized_attribute
def _from_objects(self) -> List[FromClause]:
t = self.table
if t is not None:
return [t]
else:
return []
@HasMemoized.memoized_attribute
def _render_label_in_columns_clause(self):
return self.table is not None
@property
def _ddl_label(self):
return self._gen_tq_label(self.name, dedupe_on_key=False)
def _compare_name_for_result(self, other):
if (
self.is_literal
or self.table is None
or self.table._is_textual
or not hasattr(other, "proxy_set")
or (
isinstance(other, ColumnClause)
and (
other.is_literal
or other.table is None
or other.table._is_textual
)
)
):
return (hasattr(other, "name") and self.name == other.name) or (
hasattr(other, "_tq_label")
and self._tq_label == other._tq_label
)
else:
return other.proxy_set.intersection(self.proxy_set)
def _gen_tq_label(
self, name: str, dedupe_on_key: bool = True
) -> Optional[str]:
"""generate table-qualified label
for a table-bound column this is <tablename>_<columnname>.
used primarily for LABEL_STYLE_TABLENAME_PLUS_COL
as well as the .columns collection on a Join object.
"""
label: str
t = self.table
if self.is_literal:
return None
elif t is not None and is_named_from_clause(t):
if has_schema_attr(t) and t.schema:
label = t.schema.replace(".", "_") + "_" + t.name + "_" + name
else:
assert not TYPE_CHECKING or isinstance(t, NamedFromClause)
label = t.name + "_" + name
# propagate name quoting rules for labels.
if is_quoted_name(name) and name.quote is not None:
if is_quoted_name(label):
label.quote = name.quote
else:
label = quoted_name(label, name.quote)
elif is_quoted_name(t.name) and t.name.quote is not None:
# can't get this situation to occur, so let's
# assert false on it for now
assert not isinstance(label, quoted_name)
label = quoted_name(label, t.name.quote)
if dedupe_on_key:
# ensure the label name doesn't conflict with that of an
# existing column. note that this implies that any Column
# must **not** set up its _label before its parent table has
# all of its other Column objects set up. There are several
# tables in the test suite which will fail otherwise; example:
# table "owner" has columns "name" and "owner_name". Therefore
# column owner.name cannot use the label "owner_name", it has
# to be "owner_name_1".
if label in t.c:
_label = label
counter = 1
while _label in t.c:
_label = label + "_" + str(counter)
counter += 1
label = _label
return coercions.expect(roles.TruncatedLabelRole, label)
else:
return name
def _make_proxy(
self,
selectable: FromClause,
*,
name: Optional[str] = None,
key: Optional[str] = None,
name_is_truncatable: bool = False,
compound_select_cols: Optional[Sequence[ColumnElement[Any]]] = None,
disallow_is_literal: bool = False,
**kw: Any,
) -> typing_Tuple[str, ColumnClause[_T]]:
# the "is_literal" flag normally should never be propagated; a proxied
# column is always a SQL identifier and never the actual expression
# being evaluated. however, there is a case where the "is_literal" flag
# might be used to allow the given identifier to have a fixed quoting
# pattern already, so maintain the flag for the proxy unless a
# :class:`.Label` object is creating the proxy. See [ticket:4730].
is_literal = (
not disallow_is_literal
and self.is_literal
and (
# note this does not accommodate for quoted_name differences
# right now
name is None
or name == self.name
)
)
c = self._constructor(
coercions.expect(roles.TruncatedLabelRole, name or self.name)
if name_is_truncatable
else (name or self.name),
type_=self.type,
_selectable=selectable,
is_literal=is_literal,
)
c._propagate_attrs = selectable._propagate_attrs
if name is None:
c.key = self.key
if compound_select_cols:
c._proxies = list(compound_select_cols)
else:
c._proxies = [self]
if selectable._is_clone_of is not None:
c._is_clone_of = selectable._is_clone_of.columns.get(c.key)
return c.key, c
class TableValuedColumn(NamedColumn[_T]):
__visit_name__ = "table_valued_column"
_traverse_internals: _TraverseInternalsType = [
("name", InternalTraversal.dp_anon_name),
("type", InternalTraversal.dp_type),
("scalar_alias", InternalTraversal.dp_clauseelement),
]
def __init__(self, scalar_alias: NamedFromClause, type_: TypeEngine[_T]):
self.scalar_alias = scalar_alias
self.key = self.name = scalar_alias.name
self.type = type_
def _copy_internals(
self, clone: _CloneCallableType = _clone, **kw: Any
) -> None:
self.scalar_alias = clone(self.scalar_alias, **kw)
self.key = self.name = self.scalar_alias.name
@util.ro_non_memoized_property
def _from_objects(self) -> List[FromClause]:
return [self.scalar_alias]
class CollationClause(ColumnElement[str]):
__visit_name__ = "collation"
_traverse_internals: _TraverseInternalsType = [
("collation", InternalTraversal.dp_string)
]
@classmethod
def _create_collation_expression(
cls, expression: _ColumnExpressionArgument[str], collation: str
) -> BinaryExpression[str]:
expr = coercions.expect(roles.ExpressionElementRole[str], expression)
return BinaryExpression(
expr,
CollationClause(collation),
operators.collate,
type_=expr.type,
)
def __init__(self, collation):
self.collation = collation
class _IdentifiedClause(Executable, ClauseElement):
__visit_name__ = "identified"
def __init__(self, ident):
self.ident = ident
class SavepointClause(_IdentifiedClause):
__visit_name__ = "savepoint"
inherit_cache = False
class RollbackToSavepointClause(_IdentifiedClause):
__visit_name__ = "rollback_to_savepoint"
inherit_cache = False
class ReleaseSavepointClause(_IdentifiedClause):
__visit_name__ = "release_savepoint"
inherit_cache = False
class quoted_name(util.MemoizedSlots, str):
"""Represent a SQL identifier combined with quoting preferences.
:class:`.quoted_name` is a Python unicode/str subclass which
represents a particular identifier name along with a
``quote`` flag. This ``quote`` flag, when set to
``True`` or ``False``, overrides automatic quoting behavior
for this identifier in order to either unconditionally quote
or to not quote the name. If left at its default of ``None``,
quoting behavior is applied to the identifier on a per-backend basis
based on an examination of the token itself.
A :class:`.quoted_name` object with ``quote=True`` is also
prevented from being modified in the case of a so-called
"name normalize" option. Certain database backends, such as
Oracle, Firebird, and DB2 "normalize" case-insensitive names
as uppercase. The SQLAlchemy dialects for these backends
convert from SQLAlchemy's lower-case-means-insensitive convention
to the upper-case-means-insensitive conventions of those backends.
The ``quote=True`` flag here will prevent this conversion from occurring
to support an identifier that's quoted as all lower case against
such a backend.
The :class:`.quoted_name` object is normally created automatically
when specifying the name for key schema constructs such as
:class:`_schema.Table`, :class:`_schema.Column`, and others.
The class can also be
passed explicitly as the name to any function that receives a name which
can be quoted. Such as to use the :meth:`_engine.Engine.has_table`
method with
an unconditionally quoted name::
from sqlalchemy import create_engine
from sqlalchemy import inspect
from sqlalchemy.sql import quoted_name
engine = create_engine("oracle+cx_oracle://some_dsn")
print(inspect(engine).has_table(quoted_name("some_table", True)))
The above logic will run the "has table" logic against the Oracle backend,
passing the name exactly as ``"some_table"`` without converting to
upper case.
.. versionadded:: 0.9.0
.. versionchanged:: 1.2 The :class:`.quoted_name` construct is now
importable from ``sqlalchemy.sql``, in addition to the previous
location of ``sqlalchemy.sql.elements``.
"""
__slots__ = "quote", "lower", "upper"
quote: Optional[bool]
@overload
@classmethod
def construct(cls, value: str, quote: Optional[bool]) -> quoted_name:
...
@overload
@classmethod
def construct(cls, value: None, quote: Optional[bool]) -> None:
...
@classmethod
def construct(
cls, value: Optional[str], quote: Optional[bool]
) -> Optional[quoted_name]:
if value is None:
return None
else:
return quoted_name(value, quote)
def __new__(cls, value: str, quote: Optional[bool]) -> quoted_name:
assert (
value is not None
), "use quoted_name.construct() for None passthrough"
if isinstance(value, cls) and (quote is None or value.quote == quote):
return value
self = super().__new__(cls, value)
self.quote = quote
return self
def __reduce__(self):
return quoted_name, (str(self), self.quote)
def _memoized_method_lower(self):
if self.quote:
return self
else:
return str(self).lower()
def _memoized_method_upper(self):
if self.quote:
return self
else:
return str(self).upper()
def _find_columns(clause: ClauseElement) -> Set[ColumnClause[Any]]:
"""locate Column objects within the given expression."""
cols: Set[ColumnClause[Any]] = set()
traverse(clause, {}, {"column": cols.add})
return cols
def _type_from_args(args):
for a in args:
if not a.type._isnull:
return a.type
else:
return type_api.NULLTYPE
def _corresponding_column_or_error(fromclause, column, require_embedded=False):
c = fromclause.corresponding_column(
column, require_embedded=require_embedded
)
if c is None:
raise exc.InvalidRequestError(
"Given column '%s', attached to table '%s', "
"failed to locate a corresponding column from table '%s'"
% (column, getattr(column, "table", None), fromclause.description)
)
return c
class AnnotatedColumnElement(Annotated):
_Annotated__element: ColumnElement[Any]
def __init__(self, element, values):
Annotated.__init__(self, element, values)
for attr in (
"comparator",
"_proxy_key",
"_tq_key_label",
"_tq_label",
"_non_anon_label",
):
self.__dict__.pop(attr, None)
for attr in ("name", "key", "table"):
if self.__dict__.get(attr, False) is None:
self.__dict__.pop(attr)
def _with_annotations(self, values):
clone = super()._with_annotations(values)
clone.__dict__.pop("comparator", None)
return clone
@util.memoized_property
def name(self):
"""pull 'name' from parent, if not present"""
return self._Annotated__element.name
@util.memoized_property
def table(self):
"""pull 'table' from parent, if not present"""
return self._Annotated__element.table
@util.memoized_property
def key(self):
"""pull 'key' from parent, if not present"""
return self._Annotated__element.key
@util.memoized_property
def info(self) -> _InfoType:
if TYPE_CHECKING:
assert isinstance(self._Annotated__element, Column)
return self._Annotated__element.info
@util.memoized_property
def _anon_name_label(self) -> str:
return self._Annotated__element._anon_name_label
class _truncated_label(quoted_name):
"""A unicode subclass used to identify symbolic "
"names that may require truncation."""
__slots__ = ()
def __new__(cls, value: str, quote: Optional[bool] = None) -> Any:
quote = getattr(value, "quote", quote)
# return super(_truncated_label, cls).__new__(cls, value, quote, True)
return super().__new__(cls, value, quote)
def __reduce__(self) -> Any:
return self.__class__, (str(self), self.quote)
def apply_map(self, map_: Mapping[str, Any]) -> str:
return self
class conv(_truncated_label):
"""Mark a string indicating that a name has already been converted
by a naming convention.
This is a string subclass that indicates a name that should not be
subject to any further naming conventions.
E.g. when we create a :class:`.Constraint` using a naming convention
as follows::
m = MetaData(naming_convention={
"ck": "ck_%(table_name)s_%(constraint_name)s"
})
t = Table('t', m, Column('x', Integer),
CheckConstraint('x > 5', name='x5'))
The name of the above constraint will be rendered as ``"ck_t_x5"``.
That is, the existing name ``x5`` is used in the naming convention as the
``constraint_name`` token.
In some situations, such as in migration scripts, we may be rendering
the above :class:`.CheckConstraint` with a name that's already been
converted. In order to make sure the name isn't double-modified, the
new name is applied using the :func:`_schema.conv` marker. We can
use this explicitly as follows::
m = MetaData(naming_convention={
"ck": "ck_%(table_name)s_%(constraint_name)s"
})
t = Table('t', m, Column('x', Integer),
CheckConstraint('x > 5', name=conv('ck_t_x5')))
Where above, the :func:`_schema.conv` marker indicates that the constraint
name here is final, and the name will render as ``"ck_t_x5"`` and not
``"ck_t_ck_t_x5"``
.. versionadded:: 0.9.4
.. seealso::
:ref:`constraint_naming_conventions`
"""
__slots__ = ()
# for backwards compatibility in case
# someone is re-implementing the
# _truncated_identifier() sequence in a custom
# compiler
_generated_label = _truncated_label
class _anonymous_label(_truncated_label):
"""A unicode subclass used to identify anonymously
generated names."""
__slots__ = ()
@classmethod
def safe_construct(
cls,
seed: int,
body: str,
enclosing_label: Optional[str] = None,
sanitize_key: bool = False,
) -> _anonymous_label:
# need to escape chars that interfere with format
# strings in any case, issue #8724
body = re.sub(r"[%\(\) \$]+", "_", body)
if sanitize_key:
# sanitize_key is then an extra step used by BindParameter
body = body.strip("_")
label = "%%(%d %s)s" % (seed, body.replace("%", "%%"))
if enclosing_label:
label = "%s%s" % (enclosing_label, label)
return _anonymous_label(label)
def __add__(self, other):
if "%" in other and not isinstance(other, _anonymous_label):
other = str(other).replace("%", "%%")
else:
other = str(other)
return _anonymous_label(
quoted_name(
str.__add__(self, other),
self.quote,
)
)
def __radd__(self, other):
if "%" in other and not isinstance(other, _anonymous_label):
other = str(other).replace("%", "%%")
else:
other = str(other)
return _anonymous_label(
quoted_name(
str.__add__(other, self),
self.quote,
)
)
def apply_map(self, map_):
if self.quote is not None:
# preserve quoting only if necessary
return quoted_name(self % map_, self.quote)
else:
# else skip the constructor call
return self % map_