DevForce Community Forum : Include with Inheritance

Include with Inheritance : That's a great suggestion...

Tue, 27 Jul 2010 17:48:23 -700

Author: rhaney
Subject: 2014
Posted: 27-Jul-2010 at 5:48pm

That's a great suggestion :-)....in fact, I like it a lot better than the Include statements....(strongly typed, deep eager loading...)

Will try it out....thanks!

Include with Inheritance : Good question. The .Include functionality...

Tue, 27 Jul 2010 17:42:18 -700

Author: ting
Subject: 2014
Posted: 27-Jul-2010 at 5:42pm

Good question. The .Include functionality in LINQ (which we mirror) does not support this, but you can do this by using a projection in DevForce. I believe the query below should accomplish what you were trying to do. It returns an anonymous type, but all of the various components will still be brought into the DevForce cache.

var results = em.Catalogs.Select(c => new {

Catalog = c,

Products = c.Products,

Authors = c.Products.OfType().Select(b => b.Author),

Directors = c.Products.OfType().Select(d => d.Director)

}).Execute();

Edited by ting - 27-Jul-2010 at 5:42pm

Include with Inheritance : Let's say I have an e-commerce...

Tue, 27 Jul 2010 15:29:19 -700

Author: rhaney
Subject: 2014
Posted: 27-Jul-2010 at 3:29pm

Let's say I have an e-commerce site, with different types of products. For instance, books and dvds. I create a model with the following entities:

Catalog

Product

Book (of type Product)

Dvd (of type Product)

Author

Director

Catalog has Products (Books/Dvds)

Book has a collection of Authors

Dvd has a single Director

How would I eager load information about Books and Dvds in the same query?

I tried the following, but get an exception:

var query = from c in em.Catalogs.AddIncludePaths("Products, "Products.Authors", "Products.Director");

I was thinking a Silverlight like syntax might be nice:

var query = from c in em.Catalogs.AddIncludePaths("Products, "Products.(Book.Authors)", "Products.(Dvd.Director)");

Does such a syntax exist?