linq to sql checking for null

Question

my database field int_ParentId consist of a Null value . how would i check it for a null in this linq query . it is not working

  return _db.Categories.Where(m => m.int_ParentId==null);

Answer 1

Have you mapped you int_ParentId database field to int? type (e.g. <Column Name="int_ParentId" Type="System.Int32" DbType="Int" CanBeNull="true" />)? If yes, both:

return _db.Categories.Where(m => m.int_ParentId == null);

and

return _db.Categories.Where(m => m.int_ParentId.HasValue);

should work.