.Skip().Take() on Entity Framework Navigation Properties is executing SELECT * on my SQL Server

Question

I have a method on my generated partial class like this:

var pChildren = this.Children
    .Skip(skipRelated)
    .Take(takeRelated)
    .ToList();

Answer 1

Does it help if you call Skip on the result of Take? i.e.

table.Take(takeCount+skipCount).Skip(skipCount).ToList()

Also, see

• TOP/LIMIT Support for LINQ?

Answer 2

The problem is that you are performing a LINQ-to-Object query when you query a child collection like that. EF will load the whole collection and perform the query in memory.

If you are using EF 4 you can query like this

var pChildren = this.Children.CreateSourceQuery()
                 .OrderBy(/* */).Skip(skipRelated).Take(takeRelated);

In EF 4.1

var pChildren = context.Entry(this)
                   .Collection(e => e.Children)
                   .Query()
                   .OrderBy(/* */).Skip(skipRelated).Take(takeRelated)
                   .Load();