Auto Number ID Primary Key Custom Sequence

Imports System.Data.Odbc


Public Class Form9

    Dim koneksi As OdbcConnection

    Dim stringKoneksi As String = "DSN=localhost"

    Dim stringSQL As String


    Private Sub Form9_Load(sender As Object, e As System.EventArgs) Handles Me.Load

        koneksi = New OdbcConnection(stringKoneksi)

        stringSQL = "SELECT * FROM tanggal ORDER BY idtanggal desc"

        Dim perintah As New OdbcCommand(stringSQL, koneksi)

        Try

            koneksi.Open()

            Dim baca As OdbcDataReader = perintah.ExecuteReader

            baca.Read()

            If Not baca.HasRows Then

                TextBox1.Text = "TG" + "0001"

            Else

                TextBox1.Text = Val(Microsoft.VisualBasic.Mid(baca.Item("idtanggal").ToString, 4, 3)) + 1

                If Len(TextBox1.Text) = 1 Then

                    TextBox1.Text = "TG000" & TextBox1.Text & ""

                ElseIf Len(TextBox1.Text) = 2 Then

                    TextBox1.Text = "TG00" & TextBox1.Text & ""

                ElseIf Len(TextBox1.Text) = 3 Then

                    TextBox1.Text = "TG0" & TextBox1.Text & ""

                End If

            End If

        Catch ex As Exception

            MessageBox.Show(ex.Message)

        End Try

    End Sub