Question

I have a JET table with an auto-number as the primary key, and I would like to know how I can retrieve this number after inserting a row. I have thought of using MAX() to retrieve the row with the highest value, but am not sure how reliable this would be. Some sample code:

Dim query As String
Dim newRow As Integer
query = "INSERT INTO InvoiceNumbers (date) VALUES (" & NOW() & ");"
newRow = CurrentDb.Execute(query)

Now I know that this wouldn’t work, since Execute() won’t return the value of the primary key, but this is basically the kind of code I am looking for. I will need to use the primary key of the new row to update a number of rows in another table.

What would be the simplest / most readable way of doing this?

Answer 1

If DAO use

RS.Move 0, RS.LastModified
lngID = RS!AutoNumberFieldName

If ADO use

cn.Execute "INSERT INTO TheTable.....", , adCmdText + adExecuteNoRecords
Set rs = cn.Execute("SELECT @@Identity", , adCmdText)
Debug.Print rs.Fields(0).Value

cn being a valid ADO connection, @@Identity will return the last
Identity (Autonumber) inserted on this connection.

Note that @@Identity might be troublesome because the last generated value may not be the one you are interested in. For the Access database engine, consider a VIEW that joins two tables, both of which have the IDENTITY property, and you INSERT INTO the VIEW. For SQL Server, consider if there are triggers that in turn insert records into another table that also has the IDENTITY property.

BTW DMax would not work as if someone else inserts a record just after you’ve inserted one but before your Dmax function finishes excecuting, then you would get their record.