public NestedStorageTransaction(RealStorageTransaction ambient)
{
if (ambient == null)
{
throw new ArgumentNullException();
}
if (ambient.Connection == null)
{
throw new InvalidOperationException("No Connection");
}
if (ambient.Connection.Transaction == null)
{
throw new InvalidOperationException("No Transaction");
}
if (!(ambient.Connection.Transaction is SqlTransaction))
{
throw new NotSupportedException("Sql Server Only");
}
this.ambient = ambient;
this.name = Convert.ToBase64String(Guid.NewGuid().ToByteArray());
(this.ambient.Connection.Transaction as SqlTransaction).Save(this.name);
}
/// <summary>
/// 开始事务. 请务必使用using, 如using(var t = Storage.NewTransaction()){...}
/// 限同一线程及同一数据库及使用本类的方法进行的查询和操作. 若嵌套使用则整体视为一个事务.
/// innerNestedTranRollbackEnabled：作为外层事务的内部嵌套事务回滚是否有效，前提是数据库为Sql Server且外部事物至少访问过一次数据库，否则抛异常
/// </summary>
public static IStorageTransaction NewTransaction(bool innerNestedTranRollbackEnabled, IsolationLevel isolationLevel = IsolationLevel.ReadCommitted)
{
if (currentThreadTransaction != null && !currentThreadTransaction.Disposed)
{
if (innerNestedTranRollbackEnabled)
{
if (currentThreadTransaction.Connection == null || currentThreadTransaction.Connection.Transaction == null)
{
throw new InvalidOperationException("outer transaction should visit database once at least");
}
if (!(currentThreadTransaction.Connection.Transaction is SqlTransaction))
{
throw new NotSupportedException("SQL Server Only");
}
return(new NestedStorageTransaction(currentThreadTransaction));
}
return(EmptyStorageTransaction.Instance);
}
return(currentThreadTransaction = new RealStorageTransaction(isolationLevel));
}