请问关于VB

以下代码在运行之前要引用什么？否则提示“用户类型定义未定义”。
Option Explicit
Dim cn As New rdoConnection
Dim rs As rdoResultset
Dim SQL As String

Private Sub Command1_Click()
rs.edit

End Sub

Private Sub Command2_Click()
rs(1) = Text2.Text
rs.Update

End Sub

Private Sub Command3_Click()
rs.Close
Set rs = Nothing
cn.Close
Set cn = Nothing
Unload Me

End Sub

Private Sub Command4_Click()
rs.MoveNext
If Not (rs.EOF) Then
Text1.Text = rs(0)
Text2.Text = rs(1)
Else
rs.MoveLast
End If

End Sub

Private Sub Command5_Click()
If Not (rs.BOF) Then
Text1.Text = rs(0)
Text2.Text = rs(1)
Else
rs.MoveFirst
End If

End Sub

Private Sub Form_Load()