Although an association is a kind of join in LINQ, we can also explicitly join two tables using the Join keyword, as shown in the following code snippet:
static void TestJoin()
{
using(var NWEntities = new NorthwindEntities())
{
var categoryProducts =
from c in NWEntities.Categories
join p in NWEntities.Products
on c.CategoryID equals p.CategoryID
into productsByCategory
select new {
c.CategoryName,
productCount = productsByCategory.Count()
};
foreach (var cp in categoryProducts)
{
Console.WriteLine("There are {0} products in category {1}",
cp.productCount, cp.CategoryName);
}
}
}This was not so useful in the previous example because the Products and Categories tables are associated with a foreign key relationship. If there is no foreign key association between two...