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已经为每个科目（例如英语语言、数学）创建了一个表，并且学生表与每个科目表相关，如果有人可以编辑下面的代码以使我能够执行删除命令来删除一个，我将不胜感激从这些多个表中记录。

一个重要的问题是应该有一种方法来执行删除命令，这样相关记录也可以从任何其他主题表中删除，这些记录将在未来引入新主题时创建。

Dim cd As String

If txtName.Text = "" And cboDay.Text = "" And cboMonth.Text = "" And txtYear.Text = "" And lblAge.Text = "" And radioMale.Checked = False Or RadioFemale.Checked = False And txtGName.Text = "" And txtMPhone.Text = "" And txtEmail.Text = "" And txtAddress.Text = "" And txtCity.Text = "" And cboRegion.Text = "" And PictureBox1.ImageLocation = "" Then
    MessageBox.Show("There is no record selected to delete. Search for the record to delete.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
Else
    cd = MessageBox.Show("You are about to delete this record. Are you sure you want to delete?", "Confirm Delete", MessageBoxButtons.YesNo, MessageBoxIcon.Question)
    If cd = vbYes Then
        cmd = New SqlCommand("Delete from StudentDetails.Registration where StudentId='" & txtStudentId.Text & "'", cn)
        cmd.ExecuteNonQuery()

        cmd = New SqlCommand("Delete from StudentDetails.Students where StudentId='" & txtStudentId.Text & "'", cn)
        cmd.ExecuteNonQuery()

        cmd = New SqlCommand("Delete from ProgramDetails.EnglishLanguage where StudentId='" & txtStudentId.Text & "'", cn)
        cmd.ExecuteNonQuery()

        MessageBox.Show("Record deleted", "Deleted", MessageBoxButtons.OK, MessageBoxIcon.Information)
        Showgrid()
        txtStudentId.Clear()
        txtName.Clear()
        cboDay.Text = ""
        cboMonth.Text = ""
        lblAge.Text = ""
        txtNationality.Clear()
        If radioMale.Checked = True Then
            Sex = ""
        End If
        cboStudentType.Text = ""
        cboHouse.Text = ""
        cboRoom.Text = ""
        txtGName.Clear()
        txtMPhone.Clear()
        txtHPhone.Clear()
        txtEmail.Clear()
        txtAddress.Clear()
        txtCity.Clear()
        cboRegion.Text = ""
        PictureBox1.Image = PictureBox1.ErrorImage
        txtStudentId.Focus()
    End If
End If
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1 回答 1

1

你为什么不试试DELETE CASCADE。它比在代码中手动执行要好。

通过使用级联参照完整性约束，您可以定义 SQL Server 在用户尝试删除或更新现有外键指向的键时执行的操作。

ON DELETE CASCADE 指定如果尝试删除具有由其他表中现有行中的外键引用的键的行，则包含这些外键的所有行也将被删除。

至于您提供的代码，命令应如下所示：

cmd = New SqlCommand("Delete from StudentDetails.Registration where StudentId=" & Integer.Parse(txtStudentId.Text), cn)

尽管您应该使用参数化查询来避免 Sql Injection ：

cmd = New SqlCommand("Delete from StudentDetails.Registration where StudentId = @StudentId" , cn)
cmd.Parameters.AddWithValue("@StudentId", Integer.Parse(txtStudentId.Text))
于 2013-02-14T10:15:02.103 回答