# sql/base.py # Copyright (C) 2005-2023 the SQLAlchemy authors and contributors # # # 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 """Foundational utilities common to many sql modules. """ from __future__ import annotations import collections from enum import Enum import itertools from itertools import zip_longest import operator import re 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 MutableMapping from typing import NoReturn from typing import Optional from typing import overload from typing import Sequence from typing import Set from typing import Tuple from typing import Type from typing import TYPE_CHECKING from typing import TypeVar from typing import Union from . import roles from . import visitors from .cache_key import HasCacheKey # noqa from .cache_key import MemoizedHasCacheKey # noqa from .traversals import HasCopyInternals # noqa from .visitors import ClauseVisitor from .visitors import ExtendedInternalTraversal from .visitors import ExternallyTraversible from .visitors import InternalTraversal from .. import event from .. import exc from .. import util from ..util import HasMemoized as HasMemoized from ..util import hybridmethod from ..util import typing as compat_typing from ..util.typing import Protocol from ..util.typing import Self from ..util.typing import TypeGuard if TYPE_CHECKING: from . import coercions from . import elements from . import type_api from ._orm_types import DMLStrategyArgument from ._orm_types import SynchronizeSessionArgument from ._typing import _CLE from .elements import BindParameter from .elements import ClauseList from .elements import ColumnClause # noqa from .elements import ColumnElement from .elements import KeyedColumnElement from .elements import NamedColumn from .elements import SQLCoreOperations from .elements import TextClause from .selectable import _JoinTargetElement from .selectable import _SelectIterable from .selectable import FromClause from ..engine import Connection from ..engine import CursorResult from ..engine.interfaces import _CoreMultiExecuteParams from ..engine.interfaces import _ExecuteOptions from ..engine.interfaces import _ImmutableExecuteOptions from ..engine.interfaces import CacheStats from ..engine.interfaces import Compiled from ..engine.interfaces import CompiledCacheType from ..engine.interfaces import CoreExecuteOptionsParameter from ..engine.interfaces import Dialect from ..engine.interfaces import IsolationLevel from ..engine.interfaces import SchemaTranslateMapType from ..event import dispatcher if not TYPE_CHECKING: coercions = None # noqa elements = None # noqa type_api = None # noqa class _NoArg(Enum): NO_ARG = 0 NO_ARG = _NoArg.NO_ARG class _NoneName(Enum): NONE_NAME = 0 """indicate a 'deferred' name that was ultimately the value None.""" _NONE_NAME = _NoneName.NONE_NAME _T = TypeVar("_T", bound=Any) _Fn = TypeVar("_Fn", bound=Callable[..., Any]) _AmbiguousTableNameMap = MutableMapping[str, str] class _EntityNamespace(Protocol): def __getattr__(self, key: str) -> SQLCoreOperations[Any]: ... class _HasEntityNamespace(Protocol): @util.ro_non_memoized_property def entity_namespace(self) -> _EntityNamespace: ... def _is_has_entity_namespace(element: Any) -> TypeGuard[_HasEntityNamespace]: return hasattr(element, "entity_namespace") # Remove when https://github.com/python/mypy/issues/14640 will be fixed _Self = TypeVar("_Self", bound=Any) class Immutable: """mark a ClauseElement as 'immutable' when expressions are cloned. "immutable" objects refers to the "mutability" of an object in the context of SQL DQL and DML generation. Such as, in DQL, one can compose a SELECT or subquery of varied forms, but one cannot modify the structure of a specific table or column within DQL. :class:`.Immutable` is mostly intended to follow this concept, and as such the primary "immutable" objects are :class:`.ColumnClause`, :class:`.Column`, :class:`.TableClause`, :class:`.Table`. """ __slots__ = () _is_immutable = True def unique_params(self, *optionaldict, **kwargs): raise NotImplementedError("Immutable objects do not support copying") def params(self, *optionaldict, **kwargs): raise NotImplementedError("Immutable objects do not support copying") def _clone(self: _Self, **kw: Any) -> _Self: return self def _copy_internals( self, *, omit_attrs: Iterable[str] = (), **kw: Any ) -> None: pass class SingletonConstant(Immutable): """Represent SQL constants like NULL, TRUE, FALSE""" _is_singleton_constant = True _singleton: SingletonConstant def __new__(cls: _T, *arg: Any, **kw: Any) -> _T: return cast(_T, cls._singleton) @util.non_memoized_property def proxy_set(self) -> FrozenSet[ColumnElement[Any]]: raise NotImplementedError() @classmethod def _create_singleton(cls): obj = object.__new__(cls) obj.__init__() # type: ignore # for a long time this was an empty frozenset, meaning # a SingletonConstant would never be a "corresponding column" in # a statement. This referred to #6259. However, in #7154 we see # that we do in fact need "correspondence" to work when matching cols # in result sets, so the non-correspondence was moved to a more # specific level when we are actually adapting expressions for SQL # render only. obj.proxy_set = frozenset([obj]) cls._singleton = obj def _from_objects( *elements: Union[ ColumnElement[Any], FromClause, TextClause, _JoinTargetElement ] ) -> Iterator[FromClause]: return itertools.chain.from_iterable( [element._from_objects for element in elements] ) def _select_iterables( elements: Iterable[roles.ColumnsClauseRole], ) -> _SelectIterable: """expand tables into individual columns in the given list of column expressions. """ return itertools.chain.from_iterable( [c._select_iterable for c in elements] ) _SelfGenerativeType = TypeVar("_SelfGenerativeType", bound="_GenerativeType") class _GenerativeType(compat_typing.Protocol): def _generate(self) -> Self: ... def _generative(fn: _Fn) -> _Fn: """non-caching _generative() decorator. This is basically the legacy decorator that copies the object and runs a method on the new copy. """ @util.decorator # type: ignore def _generative( fn: _Fn, self: _SelfGenerativeType, *args: Any, **kw: Any ) -> _SelfGenerativeType: """Mark a method as generative.""" self = self._generate() x = fn(self, *args, **kw) assert x is self, "generative methods must return self" return self decorated = _generative(fn) decorated.non_generative = fn # type: ignore return decorated def _exclusive_against(*names: str, **kw: Any) -> Callable[[_Fn], _Fn]: msgs = kw.pop("msgs", {}) defaults = kw.pop("defaults", {}) getters = [ (name, operator.attrgetter(name), defaults.get(name, None)) for name in names ] @util.decorator # type: ignore def check(fn, *args, **kw): # make pylance happy by not including "self" in the argument # list self = args[0] args = args[1:] for name, getter, default_ in getters: if getter(self) is not default_: msg = msgs.get( name, "Method %s() has already been invoked on this %s construct" % (fn.__name__, self.__class__), ) raise exc.InvalidRequestError(msg) return fn(self, *args, **kw) return check # type: ignore def _clone(element, **kw): return element._clone(**kw) def _expand_cloned( elements: Iterable[_CLE], ) -> Iterable[_CLE]: """expand the given set of ClauseElements to be the set of all 'cloned' predecessors. """ # TODO: cython candidate return itertools.chain(*[x._cloned_set for x in elements]) def _cloned_intersection(a: Iterable[_CLE], b: Iterable[_CLE]) -> Set[_CLE]: """return the intersection of sets a and b, counting any overlap between 'cloned' predecessors. The returned set is in terms of the entities present within 'a'. """ all_overlap = set(_expand_cloned(a)).intersection(_expand_cloned(b)) return {elem for elem in a if all_overlap.intersection(elem._cloned_set)} def _cloned_difference(a: Iterable[_CLE], b: Iterable[_CLE]) -> Set[_CLE]: all_overlap = set(_expand_cloned(a)).intersection(_expand_cloned(b)) return { elem for elem in a if not all_overlap.intersection(elem._cloned_set) } class _DialectArgView(MutableMapping[str, Any]): """A dictionary view of dialect-level arguments in the form _. """ def __init__(self, obj): self.obj = obj def _key(self, key): try: dialect, value_key = key.split("_", 1) except ValueError as err: raise KeyError(key) from err else: return dialect, value_key def __getitem__(self, key): dialect, value_key = self._key(key) try: opt = self.obj.dialect_options[dialect] except exc.NoSuchModuleError as err: raise KeyError(key) from err else: return opt[value_key] def __setitem__(self, key, value): try: dialect, value_key = self._key(key) except KeyError as err: raise exc.ArgumentError( "Keys must be of the form _" ) from err else: self.obj.dialect_options[dialect][value_key] = value def __delitem__(self, key): dialect, value_key = self._key(key) del self.obj.dialect_options[dialect][value_key] def __len__(self): return sum( len(args._non_defaults) for args in self.obj.dialect_options.values() ) def __iter__(self): return ( "%s_%s" % (dialect_name, value_name) for dialect_name in self.obj.dialect_options for value_name in self.obj.dialect_options[ dialect_name ]._non_defaults ) class _DialectArgDict(MutableMapping[str, Any]): """A dictionary view of dialect-level arguments for a specific dialect. Maintains a separate collection of user-specified arguments and dialect-specified default arguments. """ def __init__(self): self._non_defaults = {} self._defaults = {} def __len__(self): return len(set(self._non_defaults).union(self._defaults)) def __iter__(self): return iter(set(self._non_defaults).union(self._defaults)) def __getitem__(self, key): if key in self._non_defaults: return self._non_defaults[key] else: return self._defaults[key] def __setitem__(self, key, value): self._non_defaults[key] = value def __delitem__(self, key): del self._non_defaults[key] @util.preload_module("sqlalchemy.dialects") def _kw_reg_for_dialect(dialect_name): dialect_cls = util.preloaded.dialects.registry.load(dialect_name) if dialect_cls.construct_arguments is None: return None return dict(dialect_cls.construct_arguments) class DialectKWArgs: """Establish the ability for a class to have dialect-specific arguments with defaults and constructor validation. The :class:`.DialectKWArgs` interacts with the :attr:`.DefaultDialect.construct_arguments` present on a dialect. .. seealso:: :attr:`.DefaultDialect.construct_arguments` """ __slots__ = () _dialect_kwargs_traverse_internals = [ ("dialect_options", InternalTraversal.dp_dialect_options) ] @classmethod def argument_for(cls, dialect_name, argument_name, default): """Add a new kind of dialect-specific keyword argument for this class. E.g.:: Index.argument_for("mydialect", "length", None) some_index = Index('a', 'b', mydialect_length=5) The :meth:`.DialectKWArgs.argument_for` method is a per-argument way adding extra arguments to the :attr:`.DefaultDialect.construct_arguments` dictionary. This dictionary provides a list of argument names accepted by various schema-level constructs on behalf of a dialect. New dialects should typically specify this dictionary all at once as a data member of the dialect class. The use case for ad-hoc addition of argument names is typically for end-user code that is also using a custom compilation scheme which consumes the additional arguments. :param dialect_name: name of a dialect. The dialect must be locatable, else a :class:`.NoSuchModuleError` is raised. The dialect must also include an existing :attr:`.DefaultDialect.construct_arguments` collection, indicating that it participates in the keyword-argument validation and default system, else :class:`.ArgumentError` is raised. If the dialect does not include this collection, then any keyword argument can be specified on behalf of this dialect already. All dialects packaged within SQLAlchemy include this collection, however for third party dialects, support may vary. :param argument_name: name of the parameter. :param default: default value of the parameter. .. versionadded:: 0.9.4 """ construct_arg_dictionary = DialectKWArgs._kw_registry[dialect_name] if construct_arg_dictionary is None: raise exc.ArgumentError( "Dialect '%s' does have keyword-argument " "validation and defaults enabled configured" % dialect_name ) if cls not in construct_arg_dictionary: construct_arg_dictionary[cls] = {} construct_arg_dictionary[cls][argument_name] = default @util.memoized_property def dialect_kwargs(self): """A collection of keyword arguments specified as dialect-specific options to this construct. The arguments are present here in their original ``_`` format. Only arguments that were actually passed are included; unlike the :attr:`.DialectKWArgs.dialect_options` collection, which contains all options known by this dialect including defaults. The collection is also writable; keys are accepted of the form ``_`` where the value will be assembled into the list of options. .. versionadded:: 0.9.2 .. versionchanged:: 0.9.4 The :attr:`.DialectKWArgs.dialect_kwargs` collection is now writable. .. seealso:: :attr:`.DialectKWArgs.dialect_options` - nested dictionary form """ return _DialectArgView(self) @property def kwargs(self): """A synonym for :attr:`.DialectKWArgs.dialect_kwargs`.""" return self.dialect_kwargs _kw_registry = util.PopulateDict(_kw_reg_for_dialect) def _kw_reg_for_dialect_cls(self, dialect_name): construct_arg_dictionary = DialectKWArgs._kw_registry[dialect_name] d = _DialectArgDict() if construct_arg_dictionary is None: d._defaults.update({"*": None}) else: for cls in reversed(self.__class__.__mro__): if cls in construct_arg_dictionary: d._defaults.update(construct_arg_dictionary[cls]) return d @util.memoized_property def dialect_options(self): """A collection of keyword arguments specified as dialect-specific options to this construct. This is a two-level nested registry, keyed to ```` and ````. For example, the ``postgresql_where`` argument would be locatable as:: arg = my_object.dialect_options['postgresql']['where'] .. versionadded:: 0.9.2 .. seealso:: :attr:`.DialectKWArgs.dialect_kwargs` - flat dictionary form """ return util.PopulateDict( util.portable_instancemethod(self._kw_reg_for_dialect_cls) ) def _validate_dialect_kwargs(self, kwargs: Dict[str, Any]) -> None: # validate remaining kwargs that they all specify DB prefixes if not kwargs: return for k in kwargs: m = re.match("^(.+?)_(.+)$", k) if not m: raise TypeError( "Additional arguments should be " "named _, got '%s'" % k ) dialect_name, arg_name = m.group(1, 2) try: construct_arg_dictionary = self.dialect_options[dialect_name] except exc.NoSuchModuleError: util.warn( "Can't validate argument %r; can't " "locate any SQLAlchemy dialect named %r" % (k, dialect_name) ) self.dialect_options[dialect_name] = d = _DialectArgDict() d._defaults.update({"*": None}) d._non_defaults[arg_name] = kwargs[k] else: if ( "*" not in construct_arg_dictionary and arg_name not in construct_arg_dictionary ): raise exc.ArgumentError( "Argument %r is not accepted by " "dialect %r on behalf of %r" % (k, dialect_name, self.__class__) ) else: construct_arg_dictionary[arg_name] = kwargs[k] class CompileState: """Produces additional object state necessary for a statement to be compiled. the :class:`.CompileState` class is at the base of classes that assemble state for a particular statement object that is then used by the compiler. This process is essentially an extension of the process that the SQLCompiler.visit_XYZ() method takes, however there is an emphasis on converting raw user intent into more organized structures rather than producing string output. The top-level :class:`.CompileState` for the statement being executed is also accessible when the execution context works with invoking the statement and collecting results. The production of :class:`.CompileState` is specific to the compiler, such as within the :meth:`.SQLCompiler.visit_insert`, :meth:`.SQLCompiler.visit_select` etc. methods. These methods are also responsible for associating the :class:`.CompileState` with the :class:`.SQLCompiler` itself, if the statement is the "toplevel" statement, i.e. the outermost SQL statement that's actually being executed. There can be other :class:`.CompileState` objects that are not the toplevel, such as when a SELECT subquery or CTE-nested INSERT/UPDATE/DELETE is generated. .. versionadded:: 1.4 """ __slots__ = ("statement", "_ambiguous_table_name_map") plugins: Dict[Tuple[str, str], Type[CompileState]] = {} _ambiguous_table_name_map: Optional[_AmbiguousTableNameMap] @classmethod def create_for_statement(cls, statement, compiler, **kw): # factory construction. if statement._propagate_attrs: plugin_name = statement._propagate_attrs.get( "compile_state_plugin", "default" ) klass = cls.plugins.get( (plugin_name, statement._effective_plugin_target), None ) if klass is None: klass = cls.plugins[ ("default", statement._effective_plugin_target) ] else: klass = cls.plugins[ ("default", statement._effective_plugin_target) ] if klass is cls: return cls(statement, compiler, **kw) else: return klass.create_for_statement(statement, compiler, **kw) def __init__(self, statement, compiler, **kw): self.statement = statement @classmethod def get_plugin_class( cls, statement: Executable ) -> Optional[Type[CompileState]]: plugin_name = statement._propagate_attrs.get( "compile_state_plugin", None ) if plugin_name: key = (plugin_name, statement._effective_plugin_target) if key in cls.plugins: return cls.plugins[key] # there's no case where we call upon get_plugin_class() and want # to get None back, there should always be a default. return that # if there was no plugin-specific class (e.g. Insert with "orm" # plugin) try: return cls.plugins[("default", statement._effective_plugin_target)] except KeyError: return None @classmethod def _get_plugin_class_for_plugin( cls, statement: Executable, plugin_name: str ) -> Optional[Type[CompileState]]: try: return cls.plugins[ (plugin_name, statement._effective_plugin_target) ] except KeyError: return None @classmethod def plugin_for( cls, plugin_name: str, visit_name: str ) -> Callable[[_Fn], _Fn]: def decorate(cls_to_decorate): cls.plugins[(plugin_name, visit_name)] = cls_to_decorate return cls_to_decorate return decorate class Generative(HasMemoized): """Provide a method-chaining pattern in conjunction with the @_generative decorator.""" def _generate(self) -> Self: skip = self._memoized_keys cls = self.__class__ s = cls.__new__(cls) if skip: # ensure this iteration remains atomic s.__dict__ = { k: v for k, v in self.__dict__.copy().items() if k not in skip } else: s.__dict__ = self.__dict__.copy() return s class InPlaceGenerative(HasMemoized): """Provide a method-chaining pattern in conjunction with the @_generative decorator that mutates in place.""" __slots__ = () def _generate(self): skip = self._memoized_keys # note __dict__ needs to be in __slots__ if this is used for k in skip: self.__dict__.pop(k, None) return self class HasCompileState(Generative): """A class that has a :class:`.CompileState` associated with it.""" _compile_state_plugin: Optional[Type[CompileState]] = None _attributes: util.immutabledict[str, Any] = util.EMPTY_DICT _compile_state_factory = CompileState.create_for_statement class _MetaOptions(type): """metaclass for the Options class. This metaclass is actually necessary despite the availability of the ``__init_subclass__()`` hook as this type also provides custom class-level behavior for the ``__add__()`` method. """ _cache_attrs: Tuple[str, ...] def __add__(self, other): o1 = self() if set(other).difference(self._cache_attrs): raise TypeError( "dictionary contains attributes not covered by " "Options class %s: %r" % (self, set(other).difference(self._cache_attrs)) ) o1.__dict__.update(other) return o1 if TYPE_CHECKING: def __getattr__(self, key: str) -> Any: ... def __setattr__(self, key: str, value: Any) -> None: ... def __delattr__(self, key: str) -> None: ... class Options(metaclass=_MetaOptions): """A cacheable option dictionary with defaults.""" __slots__ = () _cache_attrs: Tuple[str, ...] def __init_subclass__(cls) -> None: dict_ = cls.__dict__ cls._cache_attrs = tuple( sorted( d for d in dict_ if not d.startswith("__") and d not in ("_cache_key_traversal",) ) ) super().__init_subclass__() def __init__(self, **kw): self.__dict__.update(kw) def __add__(self, other): o1 = self.__class__.__new__(self.__class__) o1.__dict__.update(self.__dict__) if set(other).difference(self._cache_attrs): raise TypeError( "dictionary contains attributes not covered by " "Options class %s: %r" % (self, set(other).difference(self._cache_attrs)) ) o1.__dict__.update(other) return o1 def __eq__(self, other): # TODO: very inefficient. This is used only in test suites # right now. for a, b in zip_longest(self._cache_attrs, other._cache_attrs): if getattr(self, a) != getattr(other, b): return False return True def __repr__(self): # TODO: fairly inefficient, used only in debugging right now. return "%s(%s)" % ( self.__class__.__name__, ", ".join( "%s=%r" % (k, self.__dict__[k]) for k in self._cache_attrs if k in self.__dict__ ), ) @classmethod def isinstance(cls, klass: Type[Any]) -> bool: return issubclass(cls, klass) @hybridmethod def add_to_element(self, name, value): return self + {name: getattr(self, name) + value} @hybridmethod def _state_dict_inst(self) -> Mapping[str, Any]: return self.__dict__ _state_dict_const: util.immutabledict[str, Any] = util.EMPTY_DICT @_state_dict_inst.classlevel def _state_dict(cls) -> Mapping[str, Any]: return cls._state_dict_const @classmethod def safe_merge(cls, other): d = other._state_dict() # only support a merge with another object of our class # and which does not have attrs that we don't. otherwise # we risk having state that might not be part of our cache # key strategy if ( cls is not other.__class__ and other._cache_attrs and set(other._cache_attrs).difference(cls._cache_attrs) ): raise TypeError( "other element %r is not empty, is not of type %s, " "and contains attributes not covered here %r" % ( other, cls, set(other._cache_attrs).difference(cls._cache_attrs), ) ) return cls + d @classmethod def from_execution_options( cls, key, attrs, exec_options, statement_exec_options ): """process Options argument in terms of execution options. e.g.:: ( load_options, execution_options, ) = QueryContext.default_load_options.from_execution_options( "_sa_orm_load_options", { "populate_existing", "autoflush", "yield_per" }, execution_options, statement._execution_options, ) get back the Options and refresh "_sa_orm_load_options" in the exec options dict w/ the Options as well """ # common case is that no options we are looking for are # in either dictionary, so cancel for that first check_argnames = attrs.intersection( set(exec_options).union(statement_exec_options) ) existing_options = exec_options.get(key, cls) if check_argnames: result = {} for argname in check_argnames: local = "_" + argname if argname in exec_options: result[local] = exec_options[argname] elif argname in statement_exec_options: result[local] = statement_exec_options[argname] new_options = existing_options + result exec_options = util.immutabledict().merge_with( exec_options, {key: new_options} ) return new_options, exec_options else: return existing_options, exec_options if TYPE_CHECKING: def __getattr__(self, key: str) -> Any: ... def __setattr__(self, key: str, value: Any) -> None: ... def __delattr__(self, key: str) -> None: ... class CacheableOptions(Options, HasCacheKey): __slots__ = () @hybridmethod def _gen_cache_key_inst(self, anon_map, bindparams): return HasCacheKey._gen_cache_key(self, anon_map, bindparams) @_gen_cache_key_inst.classlevel def _gen_cache_key(cls, anon_map, bindparams): return (cls, ()) @hybridmethod def _generate_cache_key(self): return HasCacheKey._generate_cache_key_for_object(self) class ExecutableOption(HasCopyInternals): __slots__ = () _annotations = util.EMPTY_DICT __visit_name__ = "executable_option" _is_has_cache_key = False _is_core = True def _clone(self, **kw): """Create a shallow copy of this ExecutableOption.""" c = self.__class__.__new__(self.__class__) c.__dict__ = dict(self.__dict__) # type: ignore return c class Executable(roles.StatementRole): """Mark a :class:`_expression.ClauseElement` as supporting execution. :class:`.Executable` is a superclass for all "statement" types of objects, including :func:`select`, :func:`delete`, :func:`update`, :func:`insert`, :func:`text`. """ supports_execution: bool = True _execution_options: _ImmutableExecuteOptions = util.EMPTY_DICT _is_default_generator = False _with_options: Tuple[ExecutableOption, ...] = () _with_context_options: Tuple[ Tuple[Callable[[CompileState], None], Any], ... ] = () _compile_options: Optional[Union[Type[CacheableOptions], CacheableOptions]] _executable_traverse_internals = [ ("_with_options", InternalTraversal.dp_executable_options), ( "_with_context_options", ExtendedInternalTraversal.dp_with_context_options, ), ("_propagate_attrs", ExtendedInternalTraversal.dp_propagate_attrs), ] is_select = False is_update = False is_insert = False is_text = False is_delete = False is_dml = False if TYPE_CHECKING: __visit_name__: str 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, ) -> Tuple[ Compiled, Optional[Sequence[BindParameter[Any]]], CacheStats ]: ... def _execute_on_connection( self, connection: Connection, distilled_params: _CoreMultiExecuteParams, execution_options: CoreExecuteOptionsParameter, ) -> CursorResult[Any]: ... def _execute_on_scalar( self, connection: Connection, distilled_params: _CoreMultiExecuteParams, execution_options: CoreExecuteOptionsParameter, ) -> Any: ... @util.ro_non_memoized_property def _all_selected_columns(self): raise NotImplementedError() @property def _effective_plugin_target(self) -> str: return self.__visit_name__ @_generative def options(self, *options: ExecutableOption) -> Self: """Apply options to this statement. In the general sense, options are any kind of Python object that can be interpreted by the SQL compiler for the statement. These options can be consumed by specific dialects or specific kinds of compilers. The most commonly known kind of option are the ORM level options that apply "eager load" and other loading behaviors to an ORM query. However, options can theoretically be used for many other purposes. For background on specific kinds of options for specific kinds of statements, refer to the documentation for those option objects. .. versionchanged:: 1.4 - added :meth:`.Executable.options` to Core statement objects towards the goal of allowing unified Core / ORM querying capabilities. .. seealso:: :ref:`loading_columns` - refers to options specific to the usage of ORM queries :ref:`relationship_loader_options` - refers to options specific to the usage of ORM queries """ self._with_options += tuple( coercions.expect(roles.ExecutableOptionRole, opt) for opt in options ) return self @_generative def _set_compile_options(self, compile_options: CacheableOptions) -> Self: """Assign the compile options to a new value. :param compile_options: appropriate CacheableOptions structure """ self._compile_options = compile_options return self @_generative def _update_compile_options(self, options: CacheableOptions) -> Self: """update the _compile_options with new keys.""" assert self._compile_options is not None self._compile_options += options return self @_generative def _add_context_option( self, callable_: Callable[[CompileState], None], cache_args: Any, ) -> Self: """Add a context option to this statement. These are callable functions that will be given the CompileState object upon compilation. A second argument cache_args is required, which will be combined with the ``__code__`` identity of the function itself in order to produce a cache key. """ self._with_context_options += ((callable_, cache_args),) return self @overload def execution_options( self, *, compiled_cache: Optional[CompiledCacheType] = ..., logging_token: str = ..., isolation_level: IsolationLevel = ..., no_parameters: bool = False, stream_results: bool = False, max_row_buffer: int = ..., yield_per: int = ..., insertmanyvalues_page_size: int = ..., schema_translate_map: Optional[SchemaTranslateMapType] = ..., populate_existing: bool = False, autoflush: bool = False, synchronize_session: SynchronizeSessionArgument = ..., dml_strategy: DMLStrategyArgument = ..., is_delete_using: bool = ..., is_update_from: bool = ..., **opt: Any, ) -> Self: ... @overload def execution_options(self, **opt: Any) -> Self: ... @_generative def execution_options(self, **kw: Any) -> Self: """Set non-SQL options for the statement which take effect during execution. Execution options can be set at many scopes, including per-statement, per-connection, or per execution, using methods such as :meth:`_engine.Connection.execution_options` and parameters which accept a dictionary of options such as :paramref:`_engine.Connection.execute.execution_options` and :paramref:`_orm.Session.execute.execution_options`. The primary characteristic of an execution option, as opposed to other kinds of options such as ORM loader options, is that **execution options never affect the compiled SQL of a query, only things that affect how the SQL statement itself is invoked or how results are fetched**. That is, execution options are not part of what's accommodated by SQL compilation nor are they considered part of the cached state of a statement. The :meth:`_sql.Executable.execution_options` method is :term:`generative`, as is the case for the method as applied to the :class:`_engine.Engine` and :class:`_orm.Query` objects, which means when the method is called, a copy of the object is returned, which applies the given parameters to that new copy, but leaves the original unchanged:: statement = select(table.c.x, table.c.y) new_statement = statement.execution_options(my_option=True) An exception to this behavior is the :class:`_engine.Connection` object, where the :meth:`_engine.Connection.execution_options` method is explicitly **not** generative. The kinds of options that may be passed to :meth:`_sql.Executable.execution_options` and other related methods and parameter dictionaries include parameters that are explicitly consumed by SQLAlchemy Core or ORM, as well as arbitrary keyword arguments not defined by SQLAlchemy, which means the methods and/or parameter dictionaries may be used for user-defined parameters that interact with custom code, which may access the parameters using methods such as :meth:`_sql.Executable.get_execution_options` and :meth:`_engine.Connection.get_execution_options`, or within selected event hooks using a dedicated ``execution_options`` event parameter such as :paramref:`_events.ConnectionEvents.before_execute.execution_options` or :attr:`_orm.ORMExecuteState.execution_options`, e.g.:: from sqlalchemy import event @event.listens_for(some_engine, "before_execute") def _process_opt(conn, statement, multiparams, params, execution_options): "run a SQL function before invoking a statement" if execution_options.get("do_special_thing", False): conn.exec_driver_sql("run_special_function()") Within the scope of options that are explicitly recognized by SQLAlchemy, most apply to specific classes of objects and not others. The most common execution options include: * :paramref:`_engine.Connection.execution_options.isolation_level` - sets the isolation level for a connection or a class of connections via an :class:`_engine.Engine`. This option is accepted only by :class:`_engine.Connection` or :class:`_engine.Engine`. * :paramref:`_engine.Connection.execution_options.stream_results` - indicates results should be fetched using a server side cursor; this option is accepted by :class:`_engine.Connection`, by the :paramref:`_engine.Connection.execute.execution_options` parameter on :meth:`_engine.Connection.execute`, and additionally by :meth:`_sql.Executable.execution_options` on a SQL statement object, as well as by ORM constructs like :meth:`_orm.Session.execute`. * :paramref:`_engine.Connection.execution_options.compiled_cache` - indicates a dictionary that will serve as the :ref:`SQL compilation cache ` for a :class:`_engine.Connection` or :class:`_engine.Engine`, as well as for ORM methods like :meth:`_orm.Session.execute`. Can be passed as ``None`` to disable caching for statements. This option is not accepted by :meth:`_sql.Executable.execution_options` as it is inadvisable to carry along a compilation cache within a statement object. * :paramref:`_engine.Connection.execution_options.schema_translate_map` - a mapping of schema names used by the :ref:`Schema Translate Map ` feature, accepted by :class:`_engine.Connection`, :class:`_engine.Engine`, :class:`_sql.Executable`, as well as by ORM constructs like :meth:`_orm.Session.execute`. .. seealso:: :meth:`_engine.Connection.execution_options` :paramref:`_engine.Connection.execute.execution_options` :paramref:`_orm.Session.execute.execution_options` :ref:`orm_queryguide_execution_options` - documentation on all ORM-specific execution options """ # noqa: E501 if "isolation_level" in kw: raise exc.ArgumentError( "'isolation_level' execution option may only be specified " "on Connection.execution_options(), or " "per-engine using the isolation_level " "argument to create_engine()." ) if "compiled_cache" in kw: raise exc.ArgumentError( "'compiled_cache' execution option may only be specified " "on Connection.execution_options(), not per statement." ) self._execution_options = self._execution_options.union(kw) return self def get_execution_options(self) -> _ExecuteOptions: """Get the non-SQL options which will take effect during execution. .. versionadded:: 1.3 .. seealso:: :meth:`.Executable.execution_options` """ return self._execution_options class SchemaEventTarget(event.EventTarget): """Base class for elements that are the targets of :class:`.DDLEvents` events. This includes :class:`.SchemaItem` as well as :class:`.SchemaType`. """ dispatch: dispatcher[SchemaEventTarget] def _set_parent(self, parent: SchemaEventTarget, **kw: Any) -> None: """Associate with this SchemaEvent's parent object.""" def _set_parent_with_dispatch( self, parent: SchemaEventTarget, **kw: Any ) -> None: self.dispatch.before_parent_attach(self, parent) self._set_parent(parent, **kw) self.dispatch.after_parent_attach(self, parent) class SchemaVisitor(ClauseVisitor): """Define the visiting for ``SchemaItem`` objects.""" __traverse_options__ = {"schema_visitor": True} _COLKEY = TypeVar("_COLKEY", Union[None, str], str) _COL_co = TypeVar("_COL_co", bound="ColumnElement[Any]", covariant=True) _COL = TypeVar("_COL", bound="KeyedColumnElement[Any]") class _ColumnMetrics(Generic[_COL_co]): __slots__ = ("column",) column: _COL_co def __init__( self, collection: ColumnCollection[Any, _COL_co], col: _COL_co ): self.column = col # proxy_index being non-empty means it was initialized. # so we need to update it pi = collection._proxy_index if pi: for eps_col in col._expanded_proxy_set: pi[eps_col].add(self) def get_expanded_proxy_set(self): return self.column._expanded_proxy_set def dispose(self, collection): pi = collection._proxy_index if not pi: return for col in self.column._expanded_proxy_set: colset = pi.get(col, None) if colset: colset.discard(self) if colset is not None and not colset: del pi[col] def embedded( self, target_set: Union[ Set[ColumnElement[Any]], FrozenSet[ColumnElement[Any]] ], ) -> bool: expanded_proxy_set = self.column._expanded_proxy_set for t in target_set.difference(expanded_proxy_set): if not expanded_proxy_set.intersection(_expand_cloned([t])): return False return True class ColumnCollection(Generic[_COLKEY, _COL_co]): """Collection of :class:`_expression.ColumnElement` instances, typically for :class:`_sql.FromClause` objects. The :class:`_sql.ColumnCollection` object is most commonly available as the :attr:`_schema.Table.c` or :attr:`_schema.Table.columns` collection on the :class:`_schema.Table` object, introduced at :ref:`metadata_tables_and_columns`. The :class:`_expression.ColumnCollection` has both mapping- and sequence- like behaviors. A :class:`_expression.ColumnCollection` usually stores :class:`_schema.Column` objects, which are then accessible both via mapping style access as well as attribute access style. To access :class:`_schema.Column` objects using ordinary attribute-style access, specify the name like any other object attribute, such as below a column named ``employee_name`` is accessed:: >>> employee_table.c.employee_name To access columns that have names with special characters or spaces, index-style access is used, such as below which illustrates a column named ``employee ' payment`` is accessed:: >>> employee_table.c["employee ' payment"] As the :class:`_sql.ColumnCollection` object provides a Python dictionary interface, common dictionary method names like :meth:`_sql.ColumnCollection.keys`, :meth:`_sql.ColumnCollection.values`, and :meth:`_sql.ColumnCollection.items` are available, which means that database columns that are keyed under these names also need to use indexed access:: >>> employee_table.c["values"] The name for which a :class:`_schema.Column` would be present is normally that of the :paramref:`_schema.Column.key` parameter. In some contexts, such as a :class:`_sql.Select` object that uses a label style set using the :meth:`_sql.Select.set_label_style` method, a column of a certain key may instead be represented under a particular label name such as ``tablename_columnname``:: >>> from sqlalchemy import select, column, table >>> from sqlalchemy import LABEL_STYLE_TABLENAME_PLUS_COL >>> t = table("t", column("c")) >>> stmt = select(t).set_label_style(LABEL_STYLE_TABLENAME_PLUS_COL) >>> subq = stmt.subquery() >>> subq.c.t_c :class:`.ColumnCollection` also indexes the columns in order and allows them to be accessible by their integer position:: >>> cc[0] Column('x', Integer(), table=None) >>> cc[1] Column('y', Integer(), table=None) .. versionadded:: 1.4 :class:`_expression.ColumnCollection` allows integer-based index access to the collection. Iterating the collection yields the column expressions in order:: >>> list(cc) [Column('x', Integer(), table=None), Column('y', Integer(), table=None)] The base :class:`_expression.ColumnCollection` object can store duplicates, which can mean either two columns with the same key, in which case the column returned by key access is **arbitrary**:: >>> x1, x2 = Column('x', Integer), Column('x', Integer) >>> cc = ColumnCollection(columns=[(x1.name, x1), (x2.name, x2)]) >>> list(cc) [Column('x', Integer(), table=None), Column('x', Integer(), table=None)] >>> cc['x'] is x1 False >>> cc['x'] is x2 True Or it can also mean the same column multiple times. These cases are supported as :class:`_expression.ColumnCollection` is used to represent the columns in a SELECT statement which may include duplicates. A special subclass :class:`.DedupeColumnCollection` exists which instead maintains SQLAlchemy's older behavior of not allowing duplicates; this collection is used for schema level objects like :class:`_schema.Table` and :class:`.PrimaryKeyConstraint` where this deduping is helpful. The :class:`.DedupeColumnCollection` class also has additional mutation methods as the schema constructs have more use cases that require removal and replacement of columns. .. versionchanged:: 1.4 :class:`_expression.ColumnCollection` now stores duplicate column keys as well as the same column in multiple positions. The :class:`.DedupeColumnCollection` class is added to maintain the former behavior in those cases where deduplication as well as additional replace/remove operations are needed. """ __slots__ = "_collection", "_index", "_colset", "_proxy_index" _collection: List[Tuple[_COLKEY, _COL_co, _ColumnMetrics[_COL_co]]] _index: Dict[Union[None, str, int], Tuple[_COLKEY, _COL_co]] _proxy_index: Dict[ColumnElement[Any], Set[_ColumnMetrics[_COL_co]]] _colset: Set[_COL_co] def __init__( self, columns: Optional[Iterable[Tuple[_COLKEY, _COL_co]]] = None ): object.__setattr__(self, "_colset", set()) object.__setattr__(self, "_index", {}) object.__setattr__( self, "_proxy_index", collections.defaultdict(util.OrderedSet) ) object.__setattr__(self, "_collection", []) if columns: self._initial_populate(columns) @util.preload_module("sqlalchemy.sql.elements") def __clause_element__(self) -> ClauseList: elements = util.preloaded.sql_elements return elements.ClauseList( _literal_as_text_role=roles.ColumnsClauseRole, group=False, *self._all_columns, ) def _initial_populate( self, iter_: Iterable[Tuple[_COLKEY, _COL_co]] ) -> None: self._populate_separate_keys(iter_) @property def _all_columns(self) -> List[_COL_co]: return [col for (_, col, _) in self._collection] def keys(self) -> List[_COLKEY]: """Return a sequence of string key names for all columns in this collection.""" return [k for (k, _, _) in self._collection] def values(self) -> List[_COL_co]: """Return a sequence of :class:`_sql.ColumnClause` or :class:`_schema.Column` objects for all columns in this collection.""" return [col for (_, col, _) in self._collection] def items(self) -> List[Tuple[_COLKEY, _COL_co]]: """Return a sequence of (key, column) tuples for all columns in this collection each consisting of a string key name and a :class:`_sql.ColumnClause` or :class:`_schema.Column` object. """ return [(k, col) for (k, col, _) in self._collection] def __bool__(self) -> bool: return bool(self._collection) def __len__(self) -> int: return len(self._collection) def __iter__(self) -> Iterator[_COL_co]: # turn to a list first to maintain over a course of changes return iter([col for _, col, _ in self._collection]) @overload def __getitem__(self, key: Union[str, int]) -> _COL_co: ... @overload def __getitem__( self, key: Tuple[Union[str, int], ...] ) -> ReadOnlyColumnCollection[_COLKEY, _COL_co]: ... def __getitem__( self, key: Union[str, int, Tuple[Union[str, int], ...]] ) -> Union[ReadOnlyColumnCollection[_COLKEY, _COL_co], _COL_co]: try: if isinstance(key, tuple): return ColumnCollection( # type: ignore [self._index[sub_key] for sub_key in key] ).as_readonly() else: return self._index[key][1] except KeyError as err: if isinstance(err.args[0], int): raise IndexError(err.args[0]) from err else: raise def __getattr__(self, key: str) -> _COL_co: try: return self._index[key][1] except KeyError as err: raise AttributeError(key) from err def __contains__(self, key: str) -> bool: if key not in self._index: if not isinstance(key, str): raise exc.ArgumentError( "__contains__ requires a string argument" ) return False else: return True def compare(self, other: ColumnCollection[Any, Any]) -> bool: """Compare this :class:`_expression.ColumnCollection` to another based on the names of the keys""" for l, r in zip_longest(self, other): if l is not r: return False else: return True def __eq__(self, other: Any) -> bool: return self.compare(other) def get( self, key: str, default: Optional[_COL_co] = None ) -> Optional[_COL_co]: """Get a :class:`_sql.ColumnClause` or :class:`_schema.Column` object based on a string key name from this :class:`_expression.ColumnCollection`.""" if key in self._index: return self._index[key][1] else: return default def __str__(self) -> str: return "%s(%s)" % ( self.__class__.__name__, ", ".join(str(c) for c in self), ) def __setitem__(self, key: str, value: Any) -> NoReturn: raise NotImplementedError() def __delitem__(self, key: str) -> NoReturn: raise NotImplementedError() def __setattr__(self, key: str, obj: Any) -> NoReturn: raise NotImplementedError() def clear(self) -> NoReturn: """Dictionary clear() is not implemented for :class:`_sql.ColumnCollection`.""" raise NotImplementedError() def remove(self, column: Any) -> None: raise NotImplementedError() def update(self, iter_: Any) -> NoReturn: """Dictionary update() is not implemented for :class:`_sql.ColumnCollection`.""" raise NotImplementedError() # https://github.com/python/mypy/issues/4266 __hash__ = None # type: ignore def _populate_separate_keys( self, iter_: Iterable[Tuple[_COLKEY, _COL_co]] ) -> None: """populate from an iterator of (key, column)""" self._collection[:] = collection = [ (k, c, _ColumnMetrics(self, c)) for k, c in iter_ ] self._colset.update(c._deannotate() for _, c, _ in collection) self._index.update( {idx: (k, c) for idx, (k, c, _) in enumerate(collection)} ) self._index.update({k: (k, col) for k, col, _ in reversed(collection)}) def add( self, column: ColumnElement[Any], key: Optional[_COLKEY] = None ) -> None: """Add a column to this :class:`_sql.ColumnCollection`. .. note:: This method is **not normally used by user-facing code**, as the :class:`_sql.ColumnCollection` is usually part of an existing object such as a :class:`_schema.Table`. To add a :class:`_schema.Column` to an existing :class:`_schema.Table` object, use the :meth:`_schema.Table.append_column` method. """ colkey: _COLKEY if key is None: colkey = column.key # type: ignore else: colkey = key l = len(self._collection) # don't really know how this part is supposed to work w/ the # covariant thing _column = cast(_COL_co, column) self._collection.append( (colkey, _column, _ColumnMetrics(self, _column)) ) self._colset.add(_column._deannotate()) self._index[l] = (colkey, _column) if colkey not in self._index: self._index[colkey] = (colkey, _column) def __getstate__(self) -> Dict[str, Any]: return { "_collection": [(k, c) for k, c, _ in self._collection], "_index": self._index, } def __setstate__(self, state: Dict[str, Any]) -> None: object.__setattr__(self, "_index", state["_index"]) object.__setattr__( self, "_proxy_index", collections.defaultdict(util.OrderedSet) ) object.__setattr__( self, "_collection", [ (k, c, _ColumnMetrics(self, c)) for (k, c) in state["_collection"] ], ) object.__setattr__( self, "_colset", {col for k, col, _ in self._collection} ) def contains_column(self, col: ColumnElement[Any]) -> bool: """Checks if a column object exists in this collection""" if col not in self._colset: if isinstance(col, str): raise exc.ArgumentError( "contains_column cannot be used with string arguments. " "Use ``col_name in table.c`` instead." ) return False else: return True def as_readonly(self) -> ReadOnlyColumnCollection[_COLKEY, _COL_co]: """Return a "read only" form of this :class:`_sql.ColumnCollection`.""" return ReadOnlyColumnCollection(self) def _init_proxy_index(self): """populate the "proxy index", if empty. proxy index is added in 2.0 to provide more efficient operation for the corresponding_column() method. For reasons of both time to construct new .c collections as well as memory conservation for large numbers of large .c collections, the proxy_index is only filled if corresponding_column() is called. once filled it stays that way, and new _ColumnMetrics objects created after that point will populate it with new data. Note this case would be unusual, if not nonexistent, as it means a .c collection is being mutated after corresponding_column() were used, however it is tested in test/base/test_utils.py. """ pi = self._proxy_index if pi: return for _, _, metrics in self._collection: eps = metrics.column._expanded_proxy_set for eps_col in eps: pi[eps_col].add(metrics) def corresponding_column( self, column: _COL, require_embedded: bool = False ) -> Optional[Union[_COL, _COL_co]]: """Given a :class:`_expression.ColumnElement`, return the exported :class:`_expression.ColumnElement` object from this :class:`_expression.ColumnCollection` which corresponds to that original :class:`_expression.ColumnElement` via a common ancestor column. :param column: the target :class:`_expression.ColumnElement` to be matched. :param require_embedded: only return corresponding columns for the given :class:`_expression.ColumnElement`, if the given :class:`_expression.ColumnElement` is actually present within a sub-element of this :class:`_expression.Selectable`. Normally the column will match if it merely shares a common ancestor with one of the exported columns of this :class:`_expression.Selectable`. .. seealso:: :meth:`_expression.Selectable.corresponding_column` - invokes this method against the collection returned by :attr:`_expression.Selectable.exported_columns`. .. versionchanged:: 1.4 the implementation for ``corresponding_column`` was moved onto the :class:`_expression.ColumnCollection` itself. """ # TODO: cython candidate # don't dig around if the column is locally present if column in self._colset: return column selected_intersection, selected_metrics = None, None target_set = column.proxy_set pi = self._proxy_index if not pi: self._init_proxy_index() for current_metrics in ( mm for ts in target_set if ts in pi for mm in pi[ts] ): if not require_embedded or current_metrics.embedded(target_set): if selected_metrics is None: # no corresponding column yet, pick this one. selected_metrics = current_metrics continue current_intersection = target_set.intersection( current_metrics.column._expanded_proxy_set ) if selected_intersection is None: selected_intersection = target_set.intersection( selected_metrics.column._expanded_proxy_set ) if len(current_intersection) > len(selected_intersection): # 'current' has a larger field of correspondence than # 'selected'. i.e. selectable.c.a1_x->a1.c.x->table.c.x # matches a1.c.x->table.c.x better than # selectable.c.x->table.c.x does. selected_metrics = current_metrics selected_intersection = current_intersection elif current_intersection == selected_intersection: # they have the same field of correspondence. see # which proxy_set has fewer columns in it, which # indicates a closer relationship with the root # column. Also take into account the "weight" # attribute which CompoundSelect() uses to give # higher precedence to columns based on vertical # position in the compound statement, and discard # columns that have no reference to the target # column (also occurs with CompoundSelect) selected_col_distance = sum( [ sc._annotations.get("weight", 1) for sc in ( selected_metrics.column._uncached_proxy_list() ) if sc.shares_lineage(column) ], ) current_col_distance = sum( [ sc._annotations.get("weight", 1) for sc in ( current_metrics.column._uncached_proxy_list() ) if sc.shares_lineage(column) ], ) if current_col_distance < selected_col_distance: selected_metrics = current_metrics selected_intersection = current_intersection return selected_metrics.column if selected_metrics else None _NAMEDCOL = TypeVar("_NAMEDCOL", bound="NamedColumn[Any]") class DedupeColumnCollection(ColumnCollection[str, _NAMEDCOL]): """A :class:`_expression.ColumnCollection` that maintains deduplicating behavior. This is useful by schema level objects such as :class:`_schema.Table` and :class:`.PrimaryKeyConstraint`. The collection includes more sophisticated mutator methods as well to suit schema objects which require mutable column collections. .. versionadded:: 1.4 """ def add( self, column: ColumnElement[Any], key: Optional[str] = None ) -> None: named_column = cast(_NAMEDCOL, column) if key is not None and named_column.key != key: raise exc.ArgumentError( "DedupeColumnCollection requires columns be under " "the same key as their .key" ) key = named_column.key if key is None: raise exc.ArgumentError( "Can't add unnamed column to column collection" ) if key in self._index: existing = self._index[key][1] if existing is named_column: return self.replace(named_column) # pop out memoized proxy_set as this # operation may very well be occurring # in a _make_proxy operation util.memoized_property.reset(named_column, "proxy_set") else: l = len(self._collection) self._collection.append( (key, named_column, _ColumnMetrics(self, named_column)) ) self._colset.add(named_column._deannotate()) self._index[l] = (key, named_column) self._index[key] = (key, named_column) def _populate_separate_keys( self, iter_: Iterable[Tuple[str, _NAMEDCOL]] ) -> None: """populate from an iterator of (key, column)""" cols = list(iter_) replace_col = [] for k, col in cols: if col.key != k: raise exc.ArgumentError( "DedupeColumnCollection requires columns be under " "the same key as their .key" ) if col.name in self._index and col.key != col.name: replace_col.append(col) elif col.key in self._index: replace_col.append(col) else: self._index[k] = (k, col) self._collection.append((k, col, _ColumnMetrics(self, col))) self._colset.update(c._deannotate() for (k, c, _) in self._collection) self._index.update( (idx, (k, c)) for idx, (k, c, _) in enumerate(self._collection) ) for col in replace_col: self.replace(col) def extend(self, iter_: Iterable[_NAMEDCOL]) -> None: self._populate_separate_keys((col.key, col) for col in iter_) def remove(self, column: _NAMEDCOL) -> None: if column not in self._colset: raise ValueError( "Can't remove column %r; column is not in this collection" % column ) del self._index[column.key] self._colset.remove(column) self._collection[:] = [ (k, c, metrics) for (k, c, metrics) in self._collection if c is not column ] for metrics in self._proxy_index.get(column, ()): metrics.dispose(self) self._index.update( {idx: (k, col) for idx, (k, col, _) in enumerate(self._collection)} ) # delete higher index del self._index[len(self._collection)] def replace( self, column: _NAMEDCOL, extra_remove: Optional[Iterable[_NAMEDCOL]] = None, ) -> None: """add the given column to this collection, removing unaliased versions of this column as well as existing columns with the same key. e.g.:: t = Table('sometable', metadata, Column('col1', Integer)) t.columns.replace(Column('col1', Integer, key='columnone')) will remove the original 'col1' from the collection, and add the new column under the name 'columnname'. Used by schema.Column to override columns during table reflection. """ if extra_remove: remove_col = set(extra_remove) else: remove_col = set() # remove up to two columns based on matches of name as well as key if column.name in self._index and column.key != column.name: other = self._index[column.name][1] if other.name == other.key: remove_col.add(other) if column.key in self._index: remove_col.add(self._index[column.key][1]) new_cols: List[Tuple[str, _NAMEDCOL, _ColumnMetrics[_NAMEDCOL]]] = [] replaced = False for k, col, metrics in self._collection: if col in remove_col: if not replaced: replaced = True new_cols.append( (column.key, column, _ColumnMetrics(self, column)) ) else: new_cols.append((k, col, metrics)) if remove_col: self._colset.difference_update(remove_col) for rc in remove_col: for metrics in self._proxy_index.get(rc, ()): metrics.dispose(self) if not replaced: new_cols.append((column.key, column, _ColumnMetrics(self, column))) self._colset.add(column._deannotate()) self._collection[:] = new_cols self._index.clear() self._index.update( {idx: (k, col) for idx, (k, col, _) in enumerate(self._collection)} ) self._index.update({k: (k, col) for (k, col, _) in self._collection}) class ReadOnlyColumnCollection( util.ReadOnlyContainer, ColumnCollection[_COLKEY, _COL_co] ): __slots__ = ("_parent",) def __init__(self, collection): object.__setattr__(self, "_parent", collection) object.__setattr__(self, "_colset", collection._colset) object.__setattr__(self, "_index", collection._index) object.__setattr__(self, "_collection", collection._collection) object.__setattr__(self, "_proxy_index", collection._proxy_index) def __getstate__(self): return {"_parent": self._parent} def __setstate__(self, state): parent = state["_parent"] self.__init__(parent) # type: ignore def add(self, column: Any, key: Any = ...) -> Any: self._readonly() def extend(self, elements: Any) -> NoReturn: self._readonly() def remove(self, item: Any) -> NoReturn: self._readonly() class ColumnSet(util.OrderedSet["ColumnClause[Any]"]): def contains_column(self, col): return col in self def extend(self, cols): for col in cols: self.add(col) def __eq__(self, other): l = [] for c in other: for local in self: if c.shares_lineage(local): l.append(c == local) return elements.and_(*l) def __hash__(self): return hash(tuple(x for x in self)) def _entity_namespace( entity: Union[_HasEntityNamespace, ExternallyTraversible] ) -> _EntityNamespace: """Return the nearest .entity_namespace for the given entity. If not immediately available, does an iterate to find a sub-element that has one, if any. """ try: return cast(_HasEntityNamespace, entity).entity_namespace except AttributeError: for elem in visitors.iterate(cast(ExternallyTraversible, entity)): if _is_has_entity_namespace(elem): return elem.entity_namespace else: raise def _entity_namespace_key( entity: Union[_HasEntityNamespace, ExternallyTraversible], key: str, default: Union[SQLCoreOperations[Any], _NoArg] = NO_ARG, ) -> SQLCoreOperations[Any]: """Return an entry from an entity_namespace. Raises :class:`_exc.InvalidRequestError` rather than attribute error on not found. """ try: ns = _entity_namespace(entity) if default is not NO_ARG: return getattr(ns, key, default) else: return getattr(ns, key) # type: ignore except AttributeError as err: raise exc.InvalidRequestError( 'Entity namespace for "%s" has no property "%s"' % (entity, key) ) from err