如何渴望在列表/集合中加载对象?

问题描述

我有以下查询:

ObjectB objectBAlias = null;
ObjectC objectCAlias = null;
var query = session.QueryOver<ObjectA>();
var results = query
    .JoinAlias(x => x.listOfBs, () => objectBAlias)
    .JoinAlias(x => objectBAlias.ObjectC, () => objectCAlias)
    .TransformUsing(new DistinctRootEntityResultTransformer())
    .List<ObjectA>();

class ObjectA
{
    IList<ObjectB> listOfBs;
}

class ObjectB
{
    ObjectA a;
    ObjectC c;
}

class ObjectC
{
    int x;
}

ObjectA与ObjectC的关系为many-to-many，其中ObjectB为联接表. ObjectA具有ObjectB的列表，而ObjectB具有ObjectC的比例.我正在尝试加载ObjectC，但没有成功.

ObjectA has a many-to-many relationship to ObjectC with ObjectB being the joining table. ObjectA has a list of ObjectB's, and ObjectB has a proporty of ObjectC. I'm trying to eager load ObjectC but have had no success.

让所有ObjectC渴望加载的唯一方法是这样做:

The only way I've gotten all the ObjectCs to eager load was by doing this:

foreach (ObjectA a in results)
{
    foreach (var b in a.listOfBs)
    {
        NHibernateUtil.Initialize(b.c);
    }
}

但这似乎并不能很好地扩展.

But this doesn't seem like something that would scale very well.

推荐答案

我建议-不要尝试(急于加载多对多).而是-使用内置功能:

I would suggest - do not try that (eager loading of many-to-many). Instead - use built in feature:

19.1.5.使用批量提取

要获取更多详细信息，请检查以下内容:

To get more details check these:

• 如何在不进行NHibernate重复的情况下急切地进行负载关联?
• NHibernate Fetch/FetchManes在结果集中有很多重复，如何使用ToFuture()进行修复

• How to Eager Load Associations without duplication in NHibernate?
• NHibernate Fetch/FetchMany duplication in resultset, how to fix with ToFuture()

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