如果vb.net中存在SQL记录，必须声明标量变量吗

输入@d1， @d2和@d3

con = New SqlConnection(cs)
    con.Open()          

    Dim cb1 As String = "if exists (select Fedo from Mimos where Fedo=@d1)" + "BEGIN " + "Update Mimos Set ActivationID=@d2,Date=@d3 where Fedo=@d1)" + "END" + "Else" + "insert into Mimos (Fedo,ActivationID,Date) VALUES (@d1,@d2,@d3)"            

    cmd = New SqlCommand(cb1)
    cmd.Connection = con

    cmd.Parameters.AddWithValue("@d1", Encrypt(TextBox1.Text.Trim))
    cmd.Parameters.AddWithValue("@d2", Encrypt(TextBox2.Text.Trim()))
    cmd.Parameters.AddWithValue("@d3", System.DateTime.Now)

    cmd.ExecuteReader()

    con.Close()