Generate a sequential number (per group) when adding a row to an Access table

Question

I have an MS Access (.accdb) table with data like the following:

Location Number
-------- ------
ABC      1
DEF              


        

Answer 1

For Access 2010 and newer, this is a better way to do it. It uses the table's Before Change Data Macro to derive the next sequential number and put it in the [Number] field of the new record:

The advantages of this approach are:

• The sequence number will be applied whenever a new record is added, regardless of how it is added.
• The Excel VBA code does not have to worry about creating the sequence number; it "just happens".
• Since this code resides at the table level it should be safe for a multi-user environment.

For more information on Data Macros, see

Create a data macro