I created a many-to-many relationship between two classes.
public class Member
{
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public Guid MemberId { get; set; }
public string Name { get; set; }
public virtual ICollection<Group> Groups { get; set; }
public Member()
{
Groups = new HashSet<Group>();
}
}
public class Group
{
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public Guid GroupId { get; set; }
public string Name { get; set; }
public virtual ICollection<Member> Members { get; set; }
public Group()
{
Members = new HashSet<Member>();
}
}
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Group>().HasMany(x => x.Members).WithMany(c => c.Groups)
.Map(y =>
{
y.MapLeftKey("GroupId");
y.MapRightKey("MemberId");
y.ToTable("Group_to_Member");
});
}
This works if i test it:
var member = new Member();
member.Name = "Smith";
db.Members.Add(member);
var group = new Group();
group.Name = "Group 1";
db.Groups.Add(group);
member.Groups.Add(group);
group.Members.Add(member);
db.SaveChanges();
But how can i delete a member from a group? I tried this: var group = db.Groups.First(); db.Groups.Remove(group); db.SaveChanges();
I just keep getting "The DELETE statement conflicted with the REFERENCE constraint". So how can i tell it to first remove the association and then the entry?
