Question

I’m getting weird results from a query I thought I constructed correctly.

This query returns 2 values, which is correct:

int userId = GetUserId(); //Not exactly like this; simplified
var context = new Entities();
//Get the roles 
var relations = (from q in context.UserHasRole
                 where q.UserId == userId
                 select q).ToList();
List<Roles> roles = new List<Roles>();
foreach (var item in relations)
{
    Roles role = (from r in context.Roles
                  where r.Id == item.RoleId
                  select r).SingleOrDefault();
                  roles.Add(role);
 }
 return roles;

This query however, returns 4 values which is insanely incorrect since there are not 4 relations in the db! It returns all the possible roles. To me the query looks as if it should only return the records where the relation has both the correct userId and roleId.

            //Get the roles 
            var roles = (from q in context.Roles
                         where context.UserHasRole.Any(o => o.UserId == userId)
                         && context.UserHasRole.Any(p => p.RoleId == q.Id)
                         select q).ToList();

            return roles;

How should I construct the lambda-query?

Answer 1

I’ve not done this before but my guess is that you should do it like this:

 //Get the roles 
 var roles = (from q in context.Roles
     where context.UserHasRole.Any(o => o.UserId == userId && o.RoleId == q.Id)
     select q).ToList();

 return roles;