Linq to NHibernate 和子对象查询

Question

我有这个 Linq 查询：

var query = (from i in session.Query<Photo>()
                   where i.IsApproved == true
                   select i);

            if (topPhotoEnum.Equals(TimeModeEnum.Today))
                query = query.Where(x => x.UploadDate >= DateTime.Today 
                                       && x.UploadDate <= DateTime.Now);

 //return  query.OrderByDescending(x => x.Votes.Count).Take(number).ToList();

 return query.ToList()
           .OrderByDescending(x => x.Votes.Count).Take(number).ToList();

这里的问题是我从数据库中检索所有数据，然后我调用OrderByDescending 和Take 来过滤数据。

我更愿意让数据库过滤数据，但似乎 Linq to NHibernate 提供程序不支持.OrderByDescending(x => x.Votes.Count)，因为它是一个子集合操作。

Antlr.Runtime.NoViableAltException

NHibernate.Hql.Ast.ANTLR.ErrorCounter.ThrowQueryException() +100
NHibernate.Hql.Ast.ANTLR.HqlSqlTranslator.Translate() +305
NHibernate.Hql.Ast.ANTLR.QueryTranslatorImpl.Analyze（字符串 收藏角色）+99
NHibernate.Hql.Ast.ANTLR.QueryTranslatorImpl.DoCompile(IDictionary2 replacements, Boolean shallow, String collectionRole) +561
NHibernate.Hql.Ast.ANTLR.QueryTranslatorImpl.Compile(IDictionary2 替换，布尔浅）+44
NHibernate.Hql.Ast.ANTLR.ASTQueryTranslatorFactory.CreateQueryTranslators(IASTNode ast, String queryIdentifier, String collectionRole, Boolean shallow, IDictionary2 filters, ISessionFactoryImplementor factory) +320
NHibernate.Hql.Ast.ANTLR.ASTQueryTranslatorFactory.CreateQueryTranslators(String queryIdentifier, IQueryExpression queryExpression, String collectionRole, Boolean shallow, IDictionary2 过滤器， ISessionFactoryImplementor 工厂）+66
NHibernate.Engine.Query.HQLExpressionQueryPlan.CreateTranslators（字符串 expressionStr, IQueryExpression queryExpression, String collectionRole, Boolean shallow, IDictionary2 enabledFilters, ISessionFactoryImplementor factory) +86
NHibernate.Engine.Query.HQLExpressionQueryPlan..ctor(String expressionStr, IQueryExpression queryExpression, String collectionRole, Boolean shallow, IDictionary2 enabledFilters, ISessionFactoryImplementor 工厂）+63
NHibernate.Engine.Query.HQLExpressionQueryPlan..ctor（字符串 expressionStr, IQueryExpression queryExpression, Boolean shallow, IDictionary2 enabledFilters, ISessionFactoryImplementor factory) +53 NHibernate.Engine.Query.QueryPlanCache.GetHQLQueryPlan(IQueryExpression queryExpression, Boolean shallow, IDictionary2 enabledFilters) +249
NHibernate.Impl.AbstractSessionImpl.GetHQLQueryPlan(IQueryExpression queryExpression，布尔浅）+185
NHibernate.Impl.AbstractSessionImpl.CreateQuery(IQueryExpression 查询表达式）+158
NHibernate.Linq.NhQueryProvider.PrepareQuery（表达式表达式， IQuery&查询，NhLinqExpression&nhQuery) +82
NHibernate.Linq.NhQueryProvider.Execute(表达式表达式) +58
NHibernate.Linq.NhQueryProvider.Execute(表达式表达式) +43
Remotion.Data.Linq.QueryableBase1.GetEnumerator() +120
System.Collections.Generic.List1..ctor(IEnumerable1 collection) +315 System.Linq.Enumerable.ToList(IEnumerable1 源) +58

有人可以帮我吗？

Answer 1

这是一个已知的限制。

Link to Issue

关于你想要达到的目标有很多问题

here

and here

总结一下：用HQL、复杂子查询、sql还是用最新的NH