Question

This is for a helpdesk ticketing program I’m creating:

When the user clicks to start a ticket I want to be able to display an autonumber from mysql that corresponds with the current ticket being filled out, so that the user can track their ticket later on. I have everything set up but I’m not too sure how I can display the Ticket ID in a textbox.

Right now I have it so that the query is being ran to get the next Ticket Id number when the form loads, but I’m not sure how to display it as text in the textbox.

    'QUERY FOR NEW ID TICKET NUMBER   
Private Sub Suggestions_Load(sender As Object, e As System.EventArgs) Handles Me.Load
    Dim idQuery As String = "SELECT MAX(itID)+1 AS Expr1 FROM(TableName)"

    With cmd
        .Connection = conn
        .CommandText = idQuery
        .CommandType = CommandType.Text
    End With

    Try
        conn.Open()
        cmd.ExecuteNonQuery()
        conn.Close()
        Me.Close()
    Catch ex As Exception
        MsgBox(ex.ToString)
        conn.Close()
    End Try

Now I managed to change it to this but I’m still getting hung up cause I’m not sur eif it’s correct:

Dim conn As New MySqlConnection(connStr)
Dim cmd As New MySqlCommand()
Dim Reader As MySqlDataReader
Dim submitteddate As String

'QUERY FOR NEW ID TICKET NUMBER   
Private Sub Suggestions_Load(sender As Object, e As System.EventArgs) Handles Me.Load
    Try
        Dim idQ As String = "INSERT INTO tblit (itID, ersBugIssue, ersSubject, ersBugCategory, ersBugDate, ersBugSubmittedby, ersBugOrHelp )" & _
                                "VALUES (NULL, NULL, NULL, NULL, NULL, NULL, NULL);"
        Dim cmd As new SQLCommand()
        With cmd
            .Connection = conn
            .CommandText = idQ
        End With

        conn.Open()
        cmd.ExecuteNonQuery()
        cmd.CommandText = "SELECT LAST_INSERT_ID() as NewTicketID"
        Dim Reader As SqlDataReader = cmd.ExecuteReader()
        Reader.Read()
        MsgBox(Reader("NewTicketID"))
        Reader.Close()

        conn.Close()
        Catch ex As Exception
            MsgBox(ex.ToString)
        End Try
End Sub

Answer 1

"SELECT MAX(itID)+1 AS Expr1 FROM(TableName)"

Is a bad idea, you will run into concurrency issues very quickly.
You should run the following SQL statements instead.

INSERT INTO tablename (ID, morefields) 
  VALUES (NULL, real_values_or_place_holders);
SELECT LAST_INSERT_ID() as NewTicketID;
-- After the ticket is complete
UPDATE tablename SET morefields = <thedata> WHERE id = NewTicketID 

-- If the ticket gets cancelled:
DELETE FROM tablename WHERE id = NewTicketID

If you do it like that you will never run into issues with duplicate or wrong TicketID being issued.

If you do a select, you cannot say it’s a nonQuery.

Use the following code

Dim cmd As New SqlCommand()
cmd.Connection = conn
cmd.CommandText = "SELECT LAST_INSERT_ID() AS NewTicketID"
Dim reader As SqlDataReader = cmd.ExecuteReader()
reader.Read
MsgBox(reader("NewTicketID"))