Question

这是我在vb中的代码：

 cmd = New SqlCommand("INSERT INTO export (eDate, qty, stockID, empID, machineID, jobID, receiptNO, plateQty, eDesc) VALUES (@eDate, @qty, @stockID, @empID, @machineID, @jobID, @receiptNO, @plateQty, @eDesc)", con)
    cmd.CommandTimeout = 1000
    cmd.CommandType = CommandType.Text
    cmd.Parameters.AddWithValue("@eDate", dateTXT.Text)
    cmd.Parameters.AddWithValue("@qty", qtyTXT.Text)
    cmd.Parameters.AddWithValue("@stockID", comboStock.SelectedValue)
    cmd.Parameters.AddWithValue("@empID", comboEmp.SelectedValue)
    cmd.Parameters.AddWithValue("@machineID", comboMachine.SelectedValue)
    cmd.Parameters.AddWithValue("@jobID", comboJob.SelectedValue)
    cmd.Parameters.AddWithValue("@receiptNO", receiptTXT.Text)
    cmd.Parameters.AddWithValue("@plateQty", TextBox1.Text)
    cmd.Parameters.AddWithValue("@eDesc", descTXT.Text)

    cmd.ExecuteNonQuery()
    If (cmd.ExecuteNonQuery) Then
        cmd = New SqlCommand("UPDATE stock SET qty = qty - @qty WHERE id = '" & comboStock.SelectedValue & "'", con)
        cmd.Parameters.AddWithValue("@qty", qtyTXT.Text)
        cmd.ExecuteNonQuery()
        MsgBox.Show("Successfuly saved!")
    Else

        MessageBox.Show("Not saved!")

    End If

当我在导出表中插入记录时，我有两个表（导出和库存）它还应该更新库存项目，但我的问题是当我插入一个记录导出它时将它保存在表格副本上。我该怎么做？

Answer 1

您正在执行2次插入查询

cmd.ExecuteNonQuery()
If (cmd.ExecuteNonQuery) Then

如果要检查是否插入了某些内容，请移除顶部的ExecuteNonQuery()并将If语句更改为此。

If (cmd.ExecuteNonQuery) > 0 Then

Answer 2

这部分代码再次调用ExecuteNonQuery()：

If (cmd.ExecuteNonQuery) Then

导致重复INSERT：

的原因

SqlCommand("INSERT INTO export (eDate, qty, stockID, empID, machineID, jobID, receiptNO, plateQty, eDesc) 
            VALUES (@eDate, @qty, @stockID, @empID, @machineID, @jobID, @receiptNO, @plateQty, @eDesc)", con)

我个人会根据您的要求创建Insert trigger：

当我在导出表中插入记录时，它还应该更新库存项目

Answer 3

 cmd.ExecuteNonQuery()    '//This will insert to the DB

 '// I know you are only checking to see if the insert was successful, '
 '// but you are essentially inserting again, then testing.'
 If (cmd.ExecuteNonQuery) Then
    ...
    ...
 End If

以下是避免重复insert的一种方法。

Dim NumberOfRowsInserted = cmd.ExecuteNonQuery()
'// now this variable will hold either 1 if the insert command was successful'
'// or 0 if the insert failed'

If NumberOfRowsInserted > 0 Then
    '// do whatever'
    ...
    ...
    ...
End If

为什么SQL同时从VB复制两个记录？

3 个答案: