I have a LastModified relationship between SiteUser and GroupPost entities (1..*)
I'm trying to update reference using code below
using (myEntities ee = new myEntities())
{
GroupPost post = (from posts in ee.GroupPost.Include("SiteUser")
where posts.PostID == id select posts).First<GroupPost>();
SiteUser u = ee.SiteUser.First<SiteUser>(e => e.UserName == HttpContext.User.Identity.Name);
post.SiteUser = u;
ee.SaveChanges(); }
which throws an exception
A relationship is being added or deleted from relationship set 'SiteUserGroupPost'. Given cardinality constraints, a corresponding 'GroupPost' must also be added or deleted.
How can I bind one existing entity object to another existing object?