Nhibernate为获取生成OUTER JOIN
尽管将映射设置为Not.Nullable()和Not.LazyLoad()
出于某种原因，NH正在连接一个表两次，一次使用INNER JOIN来安抚WHERE，其次使用OUTER JOIN来选择数据。
当然，因为我们已经加入了数据，所以只使用连接表是有意义的...
SELECT
...Tables..
from Tasks taskentity0_,
outer Cases caseentity1_,
outer Grades gradeentit2_,
Cases caseentity5_
WHERE
....
我的LINQ查询是这样的：
IQueryable<TaskEntity> tasks = TaskRepo.Find(
t => t.DueDate <= DateTime.Now
&& (t.TaskInitials == userInitials || (t.TaskInitials == "" || t.TaskInitials == null))
&& t.Team.GST.Any
(x => x.Initials == userInitials
&& x.WorkType.WorkTypeCode == t.WorkType.WorkTypeCode
&& x.Team.TeamCode == t.Team.TeamCode
)
&& (t.Case.CaseOnHold <= DateTime.Now || t.Case.CaseOnHold == null || (t.SingleTask == "M" || t.SingleTask == "m"))
&& (t.Case.CaseMatter.StartsWith("0") || t.Case.CaseMatter.StartsWith("9"))
).Fetch(t => t.Case,FetchProvider)
我的参考映射：
References(x => x.Case).Column("ta_c_ref").Not.Nullable();
思考？
我们正在使用存储库模式，并重新实现了Fetch扩展方法以这种方式工作（因此将FetchProvider传入）。
此外，因为我们需要IQueryable s， QueryOver<T>不是一个选项。
我正在使用NH 3.1。
对于群众：
我们不再使用Fetch或LINQ，我们转移到HQL ...
/// <summary>
/// Interfaces for Fetch() statements
/// </summary>
public interface IFetchingProvider
{
IFetchRequest<TOriginating, TRelated> Fetch<TOriginating, TRelated>(IQueryable<TOriginating> query, Expression<Func<TOriginating, TRelated>> relatedObjectSelector);
IFetchRequest<TOriginating, TRelated> FetchMany<TOriginating, TRelated>(IQueryable<TOriginating> query, Expression<Func<TOriginating, IEnumerable<TRelated>>> relatedObjectSelector);
IFetchRequest<TQueried, TRelated> ThenFetch<TQueried, TFetch, TRelated>(IFetchRequest<TQueried, TFetch> query, Expression<Func<TFetch, TRelated>> relatedObjectSelector);
IFetchRequest<TQueried, TRelated> ThenFetchMany<TQueried, TFetch, TRelated>(IFetchRequest<TQueried, TFetch> query, Expression<Func<TFetch, IEnumerable<TRelated>>> relatedObjectSelector);
}
public class NhFetchingProvider : IFetchingProvider
{
public IFetchRequest<TOriginating, TRelated> Fetch<TOriginating, TRelated>(IQueryable<TOriginating> query, Expression<Func<TOriginating, TRelated>> relatedObjectSelector)
{
var fetch = EagerFetchingExtensionMethods.Fetch(query, relatedObjectSelector);
return new FetchRequest<TOriginating, TRelated>(fetch);
}
public IFetchRequest<TOriginating, TRelated> FetchMany<TOriginating, TRelated>(IQueryable<TOriginating> query, Expression<Func<TOriginating, IEnumerable<TRelated>>> relatedObjectSelector)
{
var fecth = EagerFetchingExtensionMethods.FetchMany(query, relatedObjectSelector);
return new FetchRequest<TOriginating, TRelated>(fecth);
}
public IFetchRequest<TQueried, TRelated> ThenFetch<TQueried, TFetch, TRelated>(IFetchRequest<TQueried, TFetch> query, Expression<Func<TFetch, TRelated>> relatedObjectSelector)
{
var impl = query as FetchRequest<TQueried, TFetch>;
var fetch = EagerFetchingExtensionMethods.ThenFetch(impl.NhFetchRequest, relatedObjectSelector);
return new FetchRequest<TQueried, TRelated>(fetch);
}
public IFetchRequest<TQueried, TRelated> ThenFetchMany<TQueried, TFetch, TRelated>(IFetchRequest<TQueried, TFetch> query, Expression<Func<TFetch, IEnumerable<TRelated>>> relatedObjectSelector)
{
var impl = query as FetchRequest<TQueried, TFetch>;
var fetch = EagerFetchingExtensionMethods.ThenFetchMany(impl.NhFetchRequest, relatedObjectSelector);
return new FetchRequest<TQueried, TRelated>(fetch);
}
}
public static IFetchRequest<TOriginating, TRelated> Fetch<TOriginating, TRelated>(this IQueryable<TOriginating> query, Expression<Func<TOriginating, TRelated>> relatedObjectSelector, Func<IFetchingProvider> FetchingProvider)
{
return FetchingProvider().Fetch(query, relatedObjectSelector);
}
在NHibernate中使用linq内部连接还不支持。 更多信息可以在这里找到：https：//nhibernate.jira.com/browse/NH-2790
我已经添加了对它的支持！
https://www.nuget.org/packages/NHibernate.Linq.InnerJoinFetch
请享用！！！
链接地址: http://www.djcxy.com/p/60997.html