Trying to traverse tables from sql database using entity framework targeting .net 3.5 websites

I'm simply trying to get data from two sql server db tables using ado.net entity framework. My code is:

    using (Model.Entities e = new Model.Entities())
    { 
       return e.PAGE.First().CONTROL;
    }

The database is setup to have two tables, a control table which links to a page table via an 'id' field in the tables (control_id). There is one CONTROL object for each PAGE object.

I keep getting a null value for my return value and I know that's not right.

I can use vis studio and breakpoints to see that there is a PAGE object in 'e' and I can see that there are multiple CONTROL objects in 'e'. This isn't a large database, I just have some sample data in there to ensure that I get this working - so I know that there should be a CONTROL object connected to this PAGE (i've verified 开发者_Python百科this through sql server).

I am very familiar with the general code syntax, I've been using LINQ for a couple of years; however, I have not done much work at all with the entity framework or ado.net 4.

It seems like if I just pull individual table data then it works fine (i.e. e.PAGE.First() .. or .. e.CONTROL.Where(x=>x.someValue.Equals('someValue') ) but if I try to pull by traversing through the tables then I get nothing back (NULL).

Hope that all makes sense.

Some questions for you:

• I assume is a 1..1 between PAGE and CONTROL,
• Is there a FK called "ControlID" on PAGE?
• Do you have a navigational property called "Control" on your "Page" entity in your EDMX?

If the answer to all of the above is Yes, then this should work:

var page = e.Pages.Include("Control").First();

Here, you are returning the First "Page" record, and eager loading the associated control.

The SQL produced should be something like this:

SELECT p.*, c.*
FROM Page p
INNER JOIN Control c
on p.ControlId = c.ControlId