Querying an Entity Data Model - Entity Framework 6 Recipes - page 78

Listing 3-16. Finding topics in a List of Categories Using Both LINQ and Entity SQL
using (var context = new EFRecipesEntities())
{
// delete previous test data
context.Database.ExecuteSqlCommand("delete from chapter3.category");
context.Database.ExecuteSqlCommand("delete from chapter3.book");
// add new test data
var cat1 = new Category { Name = "Programming" };
var cat2 = new Category { Name = "Databases" };
var cat3 = new Category {Name = "Operating Systems"};
context.Books.Add(new Book { Title = "F# In Practice", Category = cat1 });
context.Books.Add(new Book { Title = "The Joy of SQL", Category = cat2 });
context.Books.Add(new Book { Title = "Windows 7: The Untold Story",
Category = cat3 });
context.SaveChanges();
}
using (var context = new EFRecipesEntities())
{
Console.WriteLine("Books (using LINQ)");
var cats = new List<string> { "Programming", "Databases" };
var books = from b in context.Books
where cats.Contains(b.Category.Name)
select b;
foreach (var book in books)
{
Console.WriteLine("'{0}' is in category: {1}", book.Title,
book.Category.Name);
}
}
using (var context = new EFRecipesEntities())
{
Console.WriteLine("Books (using ESQL)");
var esql = @"select value b from Books as b
where b.Category.Name in {'Programming','Databases'}";
var books = ((IObjectContextAdapter)context).ObjectContext.CreateQuery<Book>(esql);
foreach (var book in books)
{
Console.WriteLine("'{0}' is in category: {1}", book.Title,
book.Category.Name);
}
}