Question

快速为您服务。我正在使用以下代码将记录插入我的mysql数据库中的两个表...

SQLConnection.ConnectionString = connectionstring
    Try
        If SQLConnection.State = ConnectionState.Closed Then
            SQLConnection.Open()
            Dim SQLStatement As String = "INSERT INTO hosts(name, description, host, type, port, hostname) VALUES('" & txtname.Text & "','" & txtdescription.Text & "','" & txthost.Text & "','" & cmbtype.Text & "','" & txtport.Text & "','" & Pinger.resolvedstatus.Text & "'); SELECT LAST_INSERT_ID()"
            SaveData(SQLStatement)

            SQLConnection.Open()
            SQLStatement = "INSERT INTO credentials(hosts_linked_id, username, password, type) VALUES('" & hosts_linked_id & "','" & txtusername.Text & "','" & txtpwd.Text & "','" & cmbtype.Text & "')"
            SaveData(SQLStatement)

Savedata()位调用此函数...

    Public Sub SaveData(ByRef SQLStatement As String)
    Dim cmd As MySqlCommand = New MySqlCommand

    cmd.CommandText = SQLStatement
    cmd.CommandType = CommandType.Text
    cmd.Connection = SQLConnection
    cmd.ExecuteNonQuery()
    hosts_linked_id = CInt(cmd.ExecuteScalar())

    SQLConnection.Close()
    MsgBox("Host has been added - Host ID " & hosts_linked_id & "")
    txtname.Text = ""
    txtdescription.Text = ""
    txthost.Text = ""
    cmbtype.Text = ""
    txtport.Text = ""
End Sub

代码正在工作，必要的记录被插入到'hosts'和'credentials'表中，但是在每个表中，记录被插入两次。

显然我不希望我的数据库中有重复记录，所以有人可以帮我阻止它执行两次插入吗？

提前致谢!!

Answer 1

你叫它两次：

cmd.ExecuteNonQuery()
hosts_linked_id = CInt(cmd.ExecuteScalar())

一次为ExecuteNonQuery，第二次为ExecuteScalar()

您需要删除其中一个。看一下代码，我想你可能需要在SaveData方法中引入一个参数来说明要使用哪一个。

Answer 2

cmd.ExecuteNonQuery()
hosts_linked_id = CInt(cmd.ExecuteScalar())

删除cmd.ExecuteNonQuery()以避免插入两次

INSERT后mysql中的重复记录

2 个答案: