Hi,
I've been using NHibernate for a while now, and these days I encounter a "funny" problem. I am not entirely sure if it's a bug so I followed the indications regarding posting bugs and I decided to first ask about it on this forum.

Suppose we have the following classes:
namespace TestBidirectional
{
public class Bid
{
private int _id;
public int Id
{
get { return _id; }
set { _id = value; }
}

public string Name
{ get; set; }

public Item Item
{ get; set; }
}

public class Item
{
private int _id;
private IList<Bid> _bids = new List<Bid>();
public int Id
{
get { return _id; }
set { _id = value; }
}

public IList<Bid> Bids
{
get { return _bids; }
}

public string Name
{ get; set; }
}
}

and corresponding mappings:

<?xml version="1.0" encoding="utf-8"?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="TestBidirectional" namespace="TestBidirectional">

<class name="Bid" table="_BIDIRECTIONAL_BID" lazy="false">
<id name="Id" type="Int32" access="nosetter.camelcase-underscore">
<generator class="identity" />
</id>
<property name="Name" column="`NAME`" type="string" length="50" />
<many-to-one name="Item" column="ITEM_ID" class="Item" not-null="true"/>
</class>
</hibernate-mapping>

<?xml version="1.0" encoding="utf-8"?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="TestBidirectional" namespace="TestBidirectional">
<class name="Item" table="BIDIRECTIONAL_ITEM" lazy="false">
<id name="Id" type="Int32" access="nosetter.camelcase-underscore">
<generator class="identity" />
</id>
<property name="Name" column="`NAME`" type="string" length="50" />
<bag name="Bids" inverse="true" cascade="all-delete-orphan" access="nosetter.camelcase-underscore">
<key>
<!--doesn't work generating tables for bidirectional classes when using backticks - error about using 2 times the same column name!!-->
<column name="`ITEM_ID`" />
<!-- in this case it works:
<column name="ITEM_ID" />-->
</key>
<one-to-many class="Bid"/>
</bag>
</class>
</hibernate-mapping>

Now when I try to create my tables using something like:

SchemaExport exp = new NHibernate.Tool.hbm2ddl.SchemaExport(config);
exp.Execute(false, true, false, false);

NHibernate raises the following error:
HNibernate.HibernateException:"Column names in each table must be unique. Column name 'ITEM_ID' in table '_BIDIRECTIONAL_BID' is specified more than once."
which is actually the message from inner System.Data.SqlClient.SqlException.

Removing backticks solves the problem though. Is it a normal behaviour for foreign key columns or a NHibernate bug?

Thanks

Dan.