Stop EF From Loading Entities When Assigning Association

Question

Using Entity framework v4, and the POCO entity generator T4 templates.

The problem I have is that the Fixup methods are loading hundreds of entities when I assign an associated entity (see line 4 below).

Dim context = New SomeEntities
Dim list = context.Lists.FirstOrDefault(Function(l) l.ListId = 2)
Dim queryDetail = context.CreateObject(Of QueryDetail)()
queryDetail.CriteriaColumnType = context.CriteriaColumnTypes.FirstOrDefault(Function(cct) cct.CriteriaColumnTypeId = 145)

The CriteriaColumnType entity that is being assigned has a collection of QueryDetail objects, and when the assignment is made, the FixUp method on the CriteriaColumnType entity is lazy loading all of the associated QueryDetails.

How can I create the FK association and attach the CriteriaColumnType entity to my QueryDetail entity without loading all of the CriteriaColumnType's QueryDetail records?

Answer 1

Do you need lazy loading here? You can turn it off:

context.ContextOptions.LazyLoadingEnabled = false

Answer 2

I ran into this problem too. An operation that used to take milliseconds started taking 3-4 seconds to run, all because I added a navigation property pointing to a large table.

I solved the problem by just deleting all the fixup code from the T4 template - our project doesn't need that functionality anyway. I deleted everything from this line:

region.Begin("Association Fixup");

to the next region.End() call. I also deleted all calls to the fixup methods from the property setters, registration of CollectionChanged handlers, and the _settingFK flag.

See this question for more on why the fixup code is there: Why is "Fixup" needed for Persistence Ignorant POCO's in EF 4?. It's trying to make sure that if you change one end of a bidirectional association, the other end is also updated. So, e.g., if you create a new BlogPost and set its User property to a user, the fixup logic will automatically add the post to the user's Posts collection.

marc_s answered the other question by linking to POCO Template Code Generation Options. Removing the fixup code from the T4 template changes the template from #2 (basic POCO with fixup) to #1 (basic POCO without fixup).