Question

as the title says, I would like to create a many-to-one relationship using Fluent NHibernate. There are GroupEntries, which belong to a Group. The Group itself can have another Group as its parent.

These are my entities:

public class GroupEnty : IGroupEnty
{
    public virtual long Id { get; set; }
    public virtual string Name { get; set; }
    ...
    public virtual IGroup Group { get; set; }
}

public class Group : IGroup
{
    public virtual long Id { get; set; }
    public virtual string Name { get; set; }
    ...
    public virtual IGroup Parent { get; set; }
}

And these are the mapping files:

public class GroupEntryMap : ClassMap<GroupEntry>
{
    public GroupEntryMap()
    {
        Table(TableNames.GroupEntry);
        Id(x => x.Id).GeneratedBy.Native();
        Map(x => x.Name).Not.Nullable();
        ...
        References<Group>(x => x.Group);
    }
}

public class GroupMap : ClassMap<Group>
{
    public GroupMap()
    {
        Table(TableNames.Group);
        Id(x => x.Id).GeneratedBy.Native();
        Map(x => x.Name).Not.Nullable();
        ...
        References<Group>(x => x.Parent);
    }
}

With this configuration, Fluent NHibernate creates these tables:

GroupEntry
bigint Id     string Name     ...     bigint Group_id

Group
bigint Id     string Name     ...     bigint Parent_id     bigint GroupEntry_id

I don’t know why it creates the column “GroupEntry_id” in the “Group” table. I am only mapping the other side of the relation. Is there an error in my configuration or is this a bug?
The fact that “GroupEntry_id” is created with a “not null” constraint gives me a lot of trouble, otherwise I would probably not care.

I’d really appreciate any help on this, it has been bugging me for a while and I cannot find any posts with a similar problem.

Edit: I do NOT want to create a bidirectional association!

Answer 1

The solution was that I accidentally assigned the same table name for two different entities… Shame on me 🙁

Thanks a lot for the input though!