Entity framework (3.5): How to translate a certain LINQ query to eSQL?

Question

Hi there,

I have the following LINQ query that I need to translate to Entity SQL /eSQL):

return (ObjectQuery<User>) from user in Users
   where !user.Roles.Any(r => r.AnIntegerProperty < 0)
   select user;

User.Roles is an navigation property to the n:m relation to Roles and there also is a Role.Users navigation property the other way round. There aren't User_Roles or Roles_User Entities available in the model, and I can't add these.

I also can't use the LINQ statement here, because I need to add .OrderBy("it." + propertyname) (comes from another source, can't change that too) later on which is not possible if the ObjectQuery is build with linq.

So how do I translate this to eSQL? And where can I find good eSQL samples? I searched for a whole day until now and must admit that eSQL reference is lousy and there aren't any usable examples around the web.

Answer 1

I think that dynamic linq library may be solution here:

http://weblogs.asp.net/scottgu/archive/2008/01/07/dynamic-linq-part-1-using-the-linq-dynamic-query-library.aspx

You can create filtering expressions using dynamic property names, so there is no need to make translations.

Answer 2

I'd write it something like

contexte.Users.Where("NOT EXISTS (SELECT VALUE r FROM it.Roles AS r WHERE  r.AnIntegerProperty < 0)")

not tested but I've already tried something similar so thi should work for you.

Answer 3

It is difficult to find an answer without knowing the specifics of what is available on Users and Roles. However, given what you have said, will the following work:

return (ObjectQuery<User>) from user in Users
                            where !(from role in dataContext.Roles
                                    where role.AnIntegerProperty < 0
                                    select role.UserId).Contains(user.UserId);

Answer 4

In case you haven't find solution, this will work

SELECT VALUE u FROM YourDataContextEntities.Users AS u WHERE NOT EXISTS(SELECT r FROM u.Roles AS r WHERE r.AnyIntegerProperty < 0)