How to delete or update using inner join in Entity Framework? - entity-framework

Question

I need to delete some records using inner join in Entity Framework.
For example, I have User, Role and UserRoleMapping tables:
User => Id, Name
Role => Id, Name
UserRoleMapping => Id, UserId, RoleId
Now I need to delete the users who belong to role with Id = 2.
I need to fire the query as shown below
Delete user
from User
inner join UserRoleMapping on User.Id = UserRoleMapping.UserId
where UserRoleMapping.RoleId = 2
Is this is possible in Entity Framework?

Answer 1

In EF you need first load entities, select items and then DeleteObject . You need do it like:
using (var context = new YourContext())
{
var item = (from user in context.User
join userRoleMapping in context.UserRoleMapping on user.Id equals userRoleMapping.UserId
where userRoleMapping.RoleId == 2
select user).ToList().ForEach(context.User.DeleteObject);
context.SaveChanges();
}
Note:
ObjectContext.DeleteObject(entity) marks the entity as Deleted in the context. (It's EntityState is Deleted after that.) If you call SaveChanges afterwards EF sends a SQL DELETE statement to the database. If no referential constraints in the database are violated the entity will be deleted, otherwise an exception is thrown
or
using (var context = new YourContext())
{
var items = (from user in context.User
join userRoleMapping in context.UserRoleMapping on user.Id equals userRoleMapping.UserId
where userRoleMapping.RoleId == 2
select user).ToList();
foreach (var item in items)
{
context.Entry(item).State = EntityState.Deleted;
}
context.SaveChanges();
}
or using ExecuteStoreCommand, here you find more
using (var context = new YourContext())
{
context.ExecuteStoreCommand("DELETE FROM USER INNER JOIN USERROLEMAPPING ON USER.ID = USERROLEMAPPING.USERID WHERE USERROLEMAPPING .ROLEID = {0}", customId);
}