added condition to lazy loading of relationship objects

no db calls will be made if foreign key is 0.
pull/4/head
kay.one 12 years ago
parent f5a68782ce
commit 28b47b415f

@ -70,14 +70,15 @@ namespace Marr.Data
internal class LazyLoaded<TParent, TChild> : LazyLoaded<TChild>
{
private TParent _parent;
private Func<IDataMapper, TParent, TChild> _query;
private Func<IDataMapper> _dbCreator;
internal LazyLoaded(Func<IDataMapper, TParent, TChild> query)
: base()
private readonly Func<IDataMapper, TParent, TChild> _query;
private readonly Func<TParent, bool> _condition;
internal LazyLoaded(Func<IDataMapper, TParent, TChild> query, Func<TParent, bool> condition = null)
{
_query = query;
_condition = condition;
}
public LazyLoaded(TChild val)
@ -107,11 +108,16 @@ namespace Marr.Data
{
if (!_isLoaded)
{
using (IDataMapper db = _dbCreator())
if (_condition != null && _condition(_parent))
{
_child = _query(db, _parent);
_isLoaded = true;
using (IDataMapper db = _dbCreator())
{
_child = _query(db, _parent);
}
}
_child = default(TChild);
_isLoaded = true;
}
}

@ -62,12 +62,13 @@ namespace Marr.Data.Mapping
/// </summary>
/// <typeparam name="TChild"></typeparam>
/// <param name="query"></param>
/// <param name="condition">condition in which a child could exist. eg. avoid call to db if foreign key is 0 or null</param>
/// <returns></returns>
public RelationshipBuilder<TEntity> LazyLoad<TChild>(Func<IDataMapper, TEntity, TChild> query)
public RelationshipBuilder<TEntity> LazyLoad<TChild>(Func<IDataMapper, TEntity, TChild> query, Func<TEntity, bool> condition = null)
{
AssertCurrentPropertyIsSet();
Relationships[_currentPropertyName].LazyLoaded = new LazyLoaded<TEntity, TChild>(query);
Relationships[_currentPropertyName].LazyLoaded = new LazyLoaded<TEntity, TChild>(query, condition);
return this;
}

@ -4,6 +4,7 @@ using System.Linq;
using FizzWare.NBuilder;
using FluentAssertions;
using NUnit.Framework;
using NzbDrone.Core.MediaFiles;
using NzbDrone.Core.Qualities;
using NzbDrone.Core.Test.Framework;
using NzbDrone.Core.Tv;
@ -72,29 +73,41 @@ namespace NzbDrone.Core.Test.Datastore
loadedSeries.Covers.Value.Should().HaveSameCount(covers);
}*/
// [Test]
// public void one_to_one()
// {
// var episode = Builder<Episode>.CreateNew()
// .With(c => c.Id = 0)
// .Build();
//
// Db.Insert(episode);
//
//
// var history = Builder<History.History>.CreateNew()
// .With(c => c.Id = 0)
// .With(c => c.EpisodeId = episode.Id)
// .With(c => c.Quality = new QualityModel())
// .Build();
//
// Db.Insert(history);
//
// var loadedEpisode = Db.Single<History.History>().Episode.Value;
//
// loadedEpisode.Should().NotBeNull();
// loadedEpisode.ShouldHave().AllProperties().But(c => c.SeriesTitle).EqualTo(episode);
// }
[Test]
public void one_to_one()
{
var episodeFile = Builder<EpisodeFile>.CreateNew()
.BuildNew();
Db.Insert(episodeFile);
var episode = Builder<Episode>.CreateNew()
.With(c => c.EpisodeFileId = episodeFile.Id)
.BuildNew();
Db.Insert(episode);
var loadedEpisodeFile = Db.Single<Episode>().EpisodeFile.Value;
loadedEpisodeFile.Should().NotBeNull();
loadedEpisodeFile.ShouldHave().AllProperties().But(c => c.DateAdded).EqualTo(episodeFile);
}
[Test]
public void one_to_one_should_not_query_db_if_foreign_key_is_zero()
{
var episode = Builder<Episode>.CreateNew()
.With(c => c.EpisodeFileId = 0)
.BuildNew();
Db.Insert(episode);
Db.Single<Episode>().EpisodeFile.Value.Should().BeNull();
}
[Test]

@ -13,8 +13,10 @@ namespace NzbDrone.Core.Datastore
where TChild : ModelBase
{
return relationshipBuilder.For(portalExpression.GetMemberName())
.LazyLoad((db, parent) => db.Query<TChild>()
.SingleOrDefault(c => c.Id == childIdSelector(parent)));
.LazyLoad(
query: (db, parent) => db.Query<TChild>().SingleOrDefault(c => c.Id == childIdSelector(parent)),
condition: parent => childIdSelector(parent) > 0
);
}

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