I have made simple model for example.
public class Publisher
{
public int Id { get; set; }
public string Title { get; set; }
public Address Location { get; set; }
public virtual ICollection<Book> Books { get; set; }
}
public class Address
{
public string Country { get; set; }
public string City { get; set; }
public string Street { get; set; }
public string HouseNumber { get; set; }
}
public class Book
{
public int Id { get; set; }
public string Title { get; set; }
public string Author { get; set; }
public int LanguageId { get; set; }
public int? PublisherId { get; set; }
}
I need to get publishers with related books. I know how to do it using linq to entities. Is it possible to solve a problem using entity sql?
public class CatalogContext : DbContext {...}
public List<Publisher> GetByCity(string city)
{
var result = new List<Publisher>();
string queryString;
queryString = String.Format(@"SELECT VALUE row(a,b)
FROM CatalogContext.Publishers AS a
join CatalogContext.Books AS b on a.Id = b.PublisherId
WHERE a.Location.City = '{0}'", city);
var rows = ((IObjectContextAdapter)_context).ObjectContext.CreateQuery<DbDataRecord>(queryString).ToList();
return ???
}
Query returns required data but it's List<DbDataRecord>
- list of pairs <publisher, book>
. How to translate it to list of publishers with filled navigation property "Books"? Is it possible to write query which directly returns List<Publisher>
?
you can do the following:
var result = ObjectContext.Publishers.Include("Books").Include("Locations")
.Where(c => c.Location.City = "SOME_CITY").Select(c => c);
Include - basically joins the table.
Then you can drill down to books by doing the following:
var test = result[0].Books;
Why are you using direct sql command instead of Entity Framework code style?
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