CompositeId and Identity_Insert - sql-server

Question

I have a class mapped like the following:
public class FooMap : ClassMap<Foo>
{
public FooMap()
{
Table("Foo");
LazyLoad();
CompositeId().KeyProperty(x => x.ID,
kp => kp.ColumnName("Id")
.Type(typeof(long)))
.KeyProperty(x => x.ValidFrom);
}
}
On the MSSQL side, Id is identity column and the table's PK is composed of Id and ValidFrom.
Here's the code I use to save:
ISession session = SessionService.GetSession();
new SqlCommand("SET IDENTITY_INSERT Foo ON",
session.Connection as SqlConnection)
.ExecuteNonQuery();
try
{
// performs various versioning checks,
// then saves using transaction.
// The session is the same as above
GenericDataService.Save(myFoo);
}
finally
{
new SqlCommand("SET IDENTITY_INSERT Foo OFF",
session.Connection as SqlConnection)
.ExecuteNonQuery();
}
Although I set Identity_Insert to ON, I get the following exception (when keeping ID and setting new ValidFrom):
Cannot insert explicit value for identity column in table 'Foo' when IDENTITY_INSERT is set to OFF.
This is the SQL executed:
INSERT INTO Foo (C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, Id, ValidFrom)
VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
Can anyone explain why I still get that exception?

Answer 1

If the problem has to do with separate transactions like Nathan Fisher suggested, then NHibernate's ITransaction.Enlist(IDbCommand) method should fix it. Try something like this:
using (var trx = session.BeginTransaction())
{
ExecuteInNHTransaction(session, "SET IDENTITY_INSERT Foo ON");
session.Save(myFoo);
ExecuteInNHTransaction(session, "SET IDENTITY_INSERT Foo OFF");
trx.Commit();
}
private static void ExecuteInNHTransaction(ISession session, string commandText)
{
var command = new SqlCommand(commandText,
(SqlConnection) session.Connection);
session.Transaction.Enlist(command);
command.ExecuteNonQuery();
}