I am mapping an existing database using Fluent NHibernate and have encountered a problem when trying to populate many-to-many collections. The database itself is not set up correctly using foreign keys, here is a simplified example of the problem I'm having.
Tables:
public class User
{
public virtual long UserID { get; set; }
public virtual string Name { get; set; }
public virtual IList<Group> Groups { get; set; }
}
public class Group
{
public virtual long GroupID { get; set; }
public virtual string Name { get; set; }
public virtual IList<User> Users { get; set; }
}
public class UserInGroup
{
public virtual User User { get; set; }
public virtual Group Group { get; set; }
#region Fluent NHibernate Composite Key Overrides
public override bool Equals(object obj)
{
if (obj == null)
return false;
var compare = obj as UserInGroup;
if (compare == null)
return false;
return User.UserID == compare.User.UserID &&
Group.GroupID == compare.Group.GroupID;
}
public override int GetHashCode()
{
return (User.UserID + "|" + Group.GroupID).GetHashCode();
}
#endregion
}
public class UserMap : ClassMap<User>
{
public UserMap()
{
Table("Users");
Id(x => x.UserID, "UserID").GeneratedBy.Identity();
Map(x => x.Name, "Name");
HasManyToMany(x => x.Groups).Table("UsersInGroups")
.ParentKeyColumn("GroupID")
.ChildKeyColumn("UserID")
.Cascade.All();
}
}
public class GroupMap : ClassMap<Group>
{
public GroupMap()
{
Table("Groups");
Id(x => x.GroupID, "GroupID").GeneratedBy.Identity();
Map(x => x.Name, "Name");
HasManyToMany(x => x.Users).Table("UsersInGroups")
.ParentKeyColumn("UserID")
.ChildKeyColumn("GroupID")
.Inverse();
}
}
public class UserInGroupMap : ClassMap<UserInGroup>
{
public UserInGroupMap()
{
Table("UsersInGroups");
CompositeId().KeyReference(x => x.User, "UserID")
.KeyReference(x => x.Group, "GroupID");
}
}
In my configuration I have eager loading enabled, the HasMany relationships seem to be working okay but the HasManyToMany relationships are returning an empty collection. I have tried a few different combinations of Cascade.All() and Inverse on the collections all with no success. Any help would be much appreciated, thanks.
HasManyToMany(x => x.Users).Table("UsersInGroups")
.ParentKeyColumn("UserID")
.ChildKeyColumn("GroupID")
.Not.LazyLoad();