Entity Framework - writing query using lambda expression

Question

I have just started Entity Framework & linq and write this query

 var query = from rp in db.UM_RolePermission
             where (from ru in db.UM_RoleUser 
             where ru.UM_User.UserID == userId select ru.RoleID).Contains(rp.RoleId)
             select rp;

above is working fine and fullfill my need, however I am trying to write this same using lambda expression to understand that as well.

I have tried himself to write this but I was unable to complete it.

var query1 = db.UM_RolePermission
             .Where(rp => (from ru in db.UM_RoleUser where ru.UM_User.UserID == userId select ru.RoleID).Contains(rp.RoleId));

Can anyone complete this?

RelationShip:

UM_RoleUser and UM_User

Thanks

Diego · Accepted Answer · 2010-08-16 16:44:37Z

4

var query = db.UM_RolePermission
            .Where(rp => db.UM_RoleUser
                         .Where(ru => ru.UM_User.UserID == userId)
                         .Select(ru => ru.RoleID)
                         .Contains(rp.RoleId))

answered Aug 16, 2010 at 16:44

Diego

20.3k5 gold badges34 silver badges46 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Dave Markle · Accepted Answer · 2010-08-16 12:02:35Z

3

I going to jump ahead and assume you've defined a relationship between RolePermission and RoleUser in a many-to-many relationship? That will make your life a lot simpler.

var query1 = db.UM_RoleUser
    .Where(ru => ru.UserId == userID)
    .SelectMany(rp => rp.RolePermissions);

Of course, this depends on how you've set up your relationships.

answered Aug 16, 2010 at 12:02

Dave Markle

98.3k20 gold badges152 silver badges172 bronze badges

2 Comments

Muhammad Akhtar Over a year ago

There is no relationship b/w RolePermission & RoleUser

Dave Markle Over a year ago

Why not make one? It certainly sounds like a natural relationship to me based on what you've told me.

Collectives™ on Stack Overflow

Entity Framework - writing query using lambda expression

2 Answers 2

Comments

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related