SQL事务是如何工作的?

所有ID均已设置且正确无误 但是当我试图保存(插入)我得到的订单时 INSERT语句与外键约束“FK_OrderItemDetail_Order”冲突。冲突发生在数据库“MyData”、表“dbo.Order”、列“OrderId”中。

create a transaction
transaction.Begin()
Insert order
Insert order.LineItems <-- error occurs here
transaction.Commit

实际代码:

...
entity.Validate();
if (entity.IsValid)
{
    SetChangedProperties(entity);
    entity.Install.NagsInstallHours = entity.TotalNagsHours;
    foreach (OrderItemDetail orderItemDetail in entity.OrderItemDetailCollection)
    {
        SetChangedOrderItemDetailProperties(orderItemDetail);
    }
    ValidateRequiredProperties(entity);
    TransactionManager transactionManager = DataRepository.Provider.CreateTransaction();
    EntityState originalEntityState = entity.EntityState;
    try
    {
        entity.OrderVehicle.OrderId = entity.OrderId;
        entity.Install.OrderId = entity.OrderId;
        transactionManager.BeginTransaction();

        SaveInsuranceInformation(transactionManager, entity);
        DataRepository.OrderProvider.Save(transactionManager, entity);
        DataRepository.OrderItemDetailProvider.Save(transactionManager, entity.OrderItemDetailCollection);             if (!entity.OrderVehicle.IsEmpty)
        {
            DataRepository.OrderVehicleProvider.Save(transactionManager, entity.OrderVehicle);
        }
        transactionManager.Commit();
    }
    catch
    {
        if (transactionManager.IsOpen)
        {
            transactionManager.Rollback();
        }
        entity.EntityState = originalEntityState;
    }
}
...

有人建议我需要使用两个事务,一个用于订单,一个用于行项目,但我有理由相信这是错误的。但我已经为此奋斗了一天多,我需要解决它,这样我就可以继续前进,即使这意味着使用一个糟糕的工作环境。我可能只是做了些傻事?