Question

下面的Visual Basic 6.0代码有什么作用？但它已被用于搜索功能，我不清楚它。所以请解释它的作用。

Private Sub cmdSearch_Click()
    Dim key As Integer, str As String
    key = InputBox("Enter the Employee No whose details u want to know: ")
    Set rs = Nothing
    str = "select * from emp where e_no=" & key
    rs.Open str, adoconn, adOpenForwardOnly, adLockReadOnly
    txtNo.Text = rs(0)
    txtName.Text = rs(1)
    txtCity.Text = rs(2)
    txtDob.Text = rs(4)
    txtPhone.Text = rs(3)
    Set rs = Nothing
    str = "select * from emp"
    rs.Open str, adoconn, adOpenDynamic, adLockPessimistic
End Sub

Answer 1

尚无人明确表示rs必须声明为As New RecordSet，以便Set rs = Nothing与Set rs = New RecordSet实际上有效相同。

Answer 2

Private Sub cmdSearch_Click()
    Dim key As Integer, str As String
    key = InputBox("Enter the Employee No whose details u want to know: ") ''// query the user for a name
    Set rs = Nothing
    str = "select * from emp where e_no=" & key ''//create sql query on the fly
    rs.Open str, adoconn, adOpenForwardOnly, adLockReadOnly ''// create a connection to an sql database
    txtNo.Text = rs(0) ''//assign the results of the query to input fields or labels
    txtName.Text = rs(1)
    txtCity.Text = rs(2)
    txtDob.Text = rs(4)
    txtPhone.Text = rs(3)
    Set rs = Nothing
    str = "select * from emp"
    rs.Open str, adoconn, adOpenDynamic, adLockPessimistic ''// creates a new sql connection and load the whole emp table
End Sub

简短摘要：向用户询问名称，并在标签或文本框中显示用户的数据。

Answer 3

它对数据库进行两次搜索。第一次搜索的结果用于填充一些文本框。第二次搜索的结果......我不知道他们在做什么。

Answer 4

它基于名为e_no的列从数据库中查找数据，将找到的行中的信息加载到TextBox控件中，然后在数据库中重新查询所有emp行。

这个Visual Basic 6.0代码做什么？

4 个答案: