I’ve been a huge fan of LINQ to SQL. But EF 3.5 (first release) didn’t quite do it for me. I didn’t like the lack of support for foreign keys, no Single() LINQ support,

An example of lack of foreign keys:

using(NorthwindEntities northwindEntities = new NorthwindEntities())
{
    Product p = new Product()
                {
                    Category = northwindEntities.Categories.Where(c => c.CategoryID == 1).First,
                    ProductName = "French fries",
                    UnitPrice = 20,
                    Discontinued = false,
                    QuantityPerUnit = "1 kg bag",
                    Supplier = northwindEntities.Suppliers.Where(s => s.SupplierID == 1).First

                };

    northwindEntities.AddToProducts(p);
    northwindEntities.SaveChanges();
}

As you can see you need to fetch  the category and the Supplier seperatly. You can’t just do CategoryID = 1

But when we launch the wizard for EF 4.0 we get this:

Which results in this:

using(NorthwindEntities northwindEntities = new NorthwindEntities())
{
    Product p = new Product()
                {
                    CategoryID = 1,
                    ProductName = "French fries",
                    UnitPrice = 20,
                    Discontinued = false,
                    QuantityPerUnit = "1 kg bag",
                    SupplierID = 1

                };

    northwindEntities.AddToProducts(p);
    northwindEntities.SaveChanges();
}

And there is Single support!

using(NorthwindEntities ne = new NorthwindEntities())
{
    var result = ne.Suppliers.Where(sup => sup.SupplierID == 1).Single();
}

So it just got a little more mature.

I’m hoping to be able to test it (and use it!) more in the future and new projects

Hope it helps

-Kristof