How to Unique Generate ID in VB 10 and MS access

Question

Dim i As Integer

    cmd.CommandText = ("SELECT Max(AccountID) FROM Accounts")
    cmd.CommandType = CommandType.Text
    cmd.Connection = cnn


    If IsDBNull(cmd.ExecuteScalar) Then
        i = AccountsDataGridView.Item(0, i).Value

        AccountIDTextBox.Text = i

    Else
        i = cmdinsert.ExecuteScalar + 1
        AccountIDTextBox.Text = i




    End If

this is my code for generate the max of ACCOUNTID

i got a problem when i clicked the button generate the problem is "ExecuteScalar: Connection property has not been initialized" HOW TO GET MAX ID TO REPLACE IN ACCOUNTTEXTBOX

If you need a sequential id, you need to do a lot more work. In VBA, you might use something like http://stackoverflow.com/questions/12517498/insert-query-with-sequential-primary-key/12528222#12528222 — Fionnuala, Mar 09 '14 at 10:32

score 0 · Answer 1 · answered Mar 09 '14 at 05:40

Well, first of all, it helps if you actually Open() your connection before you try to use it:

cnn.Open()

Secondly, if you create account numbers that way in a system that shares multiple users, you set up a race condition on your Account Id. I guess this is MS Access, so multiple users has a whole other set of problems, but still: let the database use an autonumber column instead, and don't worry about the number until you're ready to save the record.

How to Unique Generate ID in VB 10 and MS access

1 Answers1