c# - 取消数据库中的上次更新

Question

我有一个主表和一个通过引用master_gid与之关联的详细表，我必须在主表中插入摘要，在详细表中插入详细信息。一切正常。我正在关注场景:

1. 插入主表
2. 如果主表插入成功则插入明细表
3. 如果明细表插入失败，则从主表中删除引用字段

这次一切都很顺利。

在更新的情况下，我遵循相同的场景，但在详细表插入失败的情况下面临问题。如果detail_table插入失败，我如何撤消(使用查询)主表中的最后更新。 我使用 Imports System.Data.Odbc 连接到 mysql

Answer 1

这是来自 msdn 的关于 using transaction 的示例

Public Sub ExecuteTransaction(ByVal connectionString As String)

Using connection As New OdbcConnection(connectionString)
    Dim command As New OdbcCommand()
    Dim transaction As OdbcTransaction

    ' Set the Connection to the new OdbcConnection.
    command.Connection = connection

    ' Open the connection and execute the transaction. 
    Try
        connection.Open()

        ' Start a local transaction.
        transaction = connection.BeginTransaction()

        ' Assign transaction object for a pending local transaction.
        command.Connection = connection
        command.Transaction = transaction

        ' Execute the commands.
        command.CommandText = _
            "Insert into Region (RegionID, RegionDescription) VALUES (100, 'Description')"
        command.ExecuteNonQuery()
        command.CommandText = _
            "Insert into Region (RegionID, RegionDescription) VALUES (101, 'Description')"
        command.ExecuteNonQuery()

        ' Commit the transaction.
        transaction.Commit()
        Console.WriteLine("Both records are written to database.")

    Catch ex As Exception
        Console.WriteLine(ex.Message)
        ' Try to rollback the transaction 
        Try
            transaction.Rollback()

        Catch 
            ' Do nothing here; transaction is not active. 
        End Try 
    End Try 
    ' The connection is automatically closed when the 
    ' code exits the Using block. 
End Using 

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