Data Access and ObjectDataSource Control

Re: How we get data Many to many Relationship in EDM

Qasimali84 — Wed, 03 Jun 2009 14:41:02 GMT

Great hint It solved my problem

Re: How we get data Many to many Relationship in EDM

cgeers — Wed, 20 May 2009 07:12:46 GMT

Qasimali84,

Based on your question I assume the following:

You have 5 tables in your database, namely [User], [Group], [Role], [GroupRoles], [GroupUsers]
The table [GroupRoles] links roles to groups and only contains two fields which are the primary keys of the tables [Group] and [Role]
The table [GroupUsers] links users to groups and only contains two fields which are the primary keys of the tables [Group] and [User]
The tables [GroupRoles] and [GroupUsers] don't show up as separate entities in the model but are directly represented as navigation properties

Then the code to perform your two queries (Linq to Entities) is the following:

1    using (Entities context = new Entities())
2    {
3        // Display the roles of a certain group
4        var q = (from g in context.Groups
5                 where g.Id == 1
6                 select g.Roles).FirstOrDefault();
7        foreach(var role in q)
8        {
9            Console.WriteLine(role.RoleName);
10       }
11   
12       Console.WriteLine();
13       // Display the roles of a certain user
14       var q2 = (from g in context.Groups
15                 where g.Users.Any(u => u.Id == 1)
16                 select g.Roles).FirstOrDefault();
17       foreach(var role in q2)
18       {
19           Console.WriteLine(role.RoleName);
20       }
21   }

If you want the source code, just send me a private message with your e-mail address.

Regards,

Christophe

How we get data Many to many Relationship in EDM

Qasimali84 — Sat, 09 May 2009 06:36:27 GMT

I have three entities having many to many relationship in my EntityDesigner Diagram.

1. User

2.Group

3. Role

1. User Entity has following structure

Scalar Properties

UserName

Password

Active

Navigation Properties

Groups

2.Group Entities has following structure

Scalar Properties

Name

Navigation Properties

Users

Roles

3.Role Entities has following structure

Scalar Properties

Name

Navigation Properties

Groups

Now I have to
1. Show All the roles against a group id in a gride view
2. All the roles assigned against a userid in an other gride view

How this task will be accomplished using EDM.
What queries I have to write and what namespaces I have to use

Thansk in Advance.