在运行时更新数据库

Question

即使我的代码正确，我也无法更新。

我试图将数据类型从String更改为Integer，但仍然没有任何反应。

Private Sub UpdateQuanLoop()
    For x As Integer = 0 To cartidentifier - 1
        UpdateQuantity(ID(x), Quantity(x))
    Next
End Sub

Private Sub UpdateQuantity(S_ID As String, S_Quan As String)
    Dim finder As Integer
    access.AddParam("@proID", S_ID)
    access.ExecQuery("SELECT product_quantity FROM product WHERE product_ID = @proID;")

    Dim Z As DataRow = access.DBDT.Rows(0)
    finder = Z("product_quantity").ToString - S_Quan
    access.AddParam("@ID", S_ID)
    access.AddParam("@quan", finder)
    access.ExecQuery("UPDATE product SET product_quantity = @quan WHERE product_ID = @ID;")
    If NoErrors(True) = False OrElse access.RecordCount < 1 Then Exit Sub
End Sub

我没有任何错误，但数据库未更新。