Join and Include in Entity Framework

Question

Join and Include in Entity Framework

.net c# entity-framework linq sql

Question

I have the following query of linq to entities. The problem is that it doesn't seem to load the "Tags" relation even though i have included a thing for it. It works fine if i do not join on tags but i need to do that.

            var items = from i in db.Items.Include("Tags")
                        from t in i.Tags
                        where t.Text == text
                        orderby i.CreatedDate descending
                        select i;

Is there any other way to ask this query? Maybe split it up or something?

Olaj

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Craig Stuntz · Accepted Answer · 1/9/2009 1:54:02 PM

Well, the Include contradicts the where. Include says, "Load all tags." The where says, "Load some tags." When there is a contradiction between the query and Include, the query will always win.

To return all tags from any item with at least one tag == text:

        var items = from i in db.Items.Include("Tags")
                    where i.Tags.Any(t => t.Text == text)
                    orderby i.CreatedDate descending
                    select i;

(Untested, as I don't have your DB/model)

Here's a really good, free book on LINQ.

Join and Include in Entity Framework

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