Nhibernate join on a table twice
Consider the following Class structure...
public class ListViewControl
{
public int SystemId {get; set;}
public List<ControlAction> Actions {get; set;}
public List<ControlAction> ListViewActions {get; set;}
}
public class ControlAction
{
public string blahBlah {get; set;}
}
I want to load class ListViewControl eagerly using NHibernate. The mapping using Fluent is as shown below
public UIControlMap()
{
Id(x => x.SystemId);
HasMany(x => x.Actions)
.KeyColumn("ActionId")
.Cascade.AllDeleteOrphan()
.AsBag()
.Cache.ReadWrite().IncludeAll();
HasMany(x => x.ListViewActions)
.KeyColumn("ListViewActionId")
.Cascade.AllDeleteOrphan()
.AsBag()
.Cache.ReadWrite().IncludeAll();
}
This is how I am trying to load it eagerly
var baseActions = DetachedCriteria.For<ListViewControl>()
.CreateCriteria("Actions", JoinType.InnerJoin)
.SetFetchMode("BlahBlah", FetchMode.Eager)
.SetResultTransformer(new DistinctRootEntityResultTransformer());
var listViewActions = DetachedCriteria.For<ListViewControl>()
.CreateCriteria("ListViewActions", JoinType.InnerJoin)
.SetFetchMode("BlahBlah", FetchMode.Eager)
.SetResultTransformer(new DistinctRootEntityResultTransformer());
var listViews = DetachedCriteria.For<ListViewControl>()
.SetFetchMode("Actions", FetchMode.Eager)
.SetFetchMode("ListViewActions",FetchMode.Eager)
.SetResultTransformer(new DistinctRootEntityResultTransformer());
var result = _session.CreateMultiCriteria()
.Add("listViewActions", listViewActions)
.Add("baseActions", baseActions)
.Add("listViews", listViews)
.SetResultTransformer(new DistinctRootEntityResultTransformer())
.GetResult("listViews");
Now, my problem is that the class ListViewControl
get the correct records in both Actions
and ListViewActions
, but there are multiple entries of the same record. The number of records is equal to the number of joins made to the ControlAction
table, in this case two.
How can I avoid this? If I remove the SetFetchMode
from the listViews
query, the actions are loaded lazily through a proxy which I don't want.
I also tried creating aliases ...
.SetF开发者_JS百科etchMode("Actions", FetchMode.Eager)
.CreateAlias("Actions","actions",JoinType.RightOuterJoin)
.SetFetchMode("ListViewActions",FetchMode.Eager)
.CreateAlias("ListViewActions", "liactions", JoinType.RightOuterJoin)
This removed the duplicate entries, but did not eagerly load
That's an extremely inefficient way to eager load collections. Here's a better way:
http://ayende.com/Blog/archive/2010/01/16/eagerly-loading-entity-associations-efficiently-with-nhibernate.aspx
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