Chip after Dave wrote...

>I have the same need that Dave outlined in his original post so
>I am interested in seeing any and all approaches to this problem.

>  -lock the file with waiting
>  -read the current "next number" from the file
>  -increment the current "next number"
>  -write the current "next number" back to the same record
>  -unlock the file

Can't help with ODBC, but here is a JDBC snippet that I use...

  private Connection con;  // initialized somewhere else

    ...

      con.setAutoCommit(false);

      System.err.println("increment uniquekey");
      Statement st = con.createStatement();
      st.executeUpdate(
        "update "
        + dbTableUniqueCount
        + " set dbsetcounter = dbsetcounter + 1;"
      );
      st.close();

      System.err.println("retrieve uniquekey");
      st = con.createStatement();
      ResultSet rs = st.executeQuery(
        "select dbsetcounter from "
        + dbTableUniqueCount
        + ";"
      );
      rs.next();
      String uniqueKey = rs.getString("dbsetcounter");
      rs.close();
      st.close();

      System.err.println("insert customer data (etc)");
      // details snipped for brevity

      System.err.println("insert patch list");
      // details snipped for brevity

      System.err.println("commit transaction");
      con.commit();
      con.setAutoCommit(true);

    ...

Sorry, if this is off-topic re ODBC. At least it is SQL (or close ;-)

Lars "corrections welcome"