Is my IQueryable syntax correct?

Question

The generated SQL does a cross join but as the ID's are matched it acts like an inner join but is there a better performing way to do this by actually using the join keyword in C#? Is there a way where you don't have to specify how the properties join because they are all heirarchicly related anyway

Item is a Page class

PageRoles is an IQueryable property in a Page class

aspnet_Roles is an IQueryable property in a PageRole class

var item = _repository.GetByKey(999);

var f = (from fd in item.PageRoles 
         from k in fd.aspnet_Roles 
         where Roles.GetRolesForUser().Contains(k.RoleName) 
         && k.RoleId == fd.RoleId 
         select k.RoleName)
        .Count();

EDIT:

Here is an example of an IQueryable property in my classes. The below example comes from the PageRole class

public IQueryable<aspnet_Role> aspnet_Roles
{
    get
    {

          var repo=NorthCadburyWebsite.Models.aspnet_Role.GetRepo();
          return from items in repo.GetAll()
               where items.RoleId == _RoleId
               select items;
    }
}

Answer 1

I don't have my Intellisense with me but I think you can:

var f = (from fd in item.PageRoles 
         join k in fd.aspnet_Roles on k.RoleId equals fd.RoleId
         where Roles.GetRolesForUser().Contains(k.RoleName) 
         select k.RoleName)
        .Count();

Answer 2

Does this compile or do you get an error?

In this case, as you mentioned, you don't need a join. I haven't used this syntax, but it looks like you use k as a refererence (like an alias in sql syntax)

This should deliver the same result (without even using k):

var f = (from fd in item.PageRoles 
         where Roles.GetRolesForUser().Contains(fd.aspnet_Roles.RoleName) 
         && fd.aspnet_Roles.RoleId == fd.RoleId 
         select fd.aspnet_Roles.RoleName)
        .Count();

Note: Not tested, just a guess.

Answer 3

I think I'm confused, because I'm seeing the following hierarchy in your query which isn't making any sense:

[PageRoles]
|--RoleId <~~~~~~~~~.
|--[aspnet_Roles]   |
   |--RoleId ~~~~~~~*
   |--RoleName

---

Is the hierarchy determined by the RoleId and you only mean for PageRoles.RoleId to reference aspnet_Roles.RoleId? So you might have something like:

[PageRoles]  [aspnet_Roles]
|--RoleId    |--RoleId
             |--RoleName

And you're trying to make it into the following:

[PageRoles]
|--RoleId 
|--[aspnet_Roles] (where RoleId == PageRoles.RoleId)
   |--RoleName

...?

---

In which case if you can't do the following, then something is wrong with your IQueryable property definitions and not the query you have posted. Namely the method to get PageRoles's aspnet_Roles child rows is not set up properly.

var f = (from fd in item.PageRoles 
         from k in fd.aspnet_Roles 
         where Roles.GetRolesForUser().Contains(k.RoleName) 
         select k.RoleName)
        .Count();

(fd.aspnet_Roles should already be constrained by RoleId and generate an inner join).

You can check your hierarchy by seeing what SQL is generated from:

var f = from fd in item.PageRoles
        from k in fd.aspnet_Roles
        select k;

which should vaguely resemble (with something having to do with item thrown in):

SELECT k.RoleName, k.SomethingElse
FROM PageRoles fd
INNER JOIN aspnetRoles k ON fd.RoleId = k.RoleId;

---

I'm sure I'm missing something, so please help me fill in the blanks...