CompositeId和IDENTITY_INSERT

Question

我制訂類似下面的類：

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); 
    } 
} 

在MSSQL側，編號爲標識列和表的PK是由Id和ValidFrom。

這裏是我用來保存代碼：

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(); 
} 

雖然我設置Identity_Insert到ON，我得到下面的異常（保持ID時和設置新ValidFrom）：

Cannot insert explicit value for identity column in table 'Foo' when IDENTITY_INSERT is set to OFF. 

這是執行的SQL：

INSERT INTO Foo (C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, Id, ValidFrom) 
    VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?) 

任何人都可以解釋爲什麼我仍然得到這個異常？

Answer 1

如果問題與建議的Nathan Fisher等單獨事務有關，那麼NHibernate的ITransaction.Enlist(IDbCommand)方法應該修復它。嘗試是這樣的：

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(); 
}