NexusDB

NexusDB tracks a "autoinc" value in the file header. This value starts out as 0 on a newly created table. GetAutoIncValue directly returns this value. SetAutoIncValue directly sets this value.

When a record is inserted the server checks if it contains an autoinc field and if the field is still NULL. If yes it increments the autoinc value in the table header and assigned the incremented value to the autoinc field.

That means:

To achieve this the code should look like this:

var

 AutoIncValue: TnxWord32;

with nxTable, Database do begin

 StartTransactionWith([nxTable]);

 try

   Append;

   try

     GetAutoIncValue(AutoIncValue);

     Inc(AutoIncValue);

     AutoIncField.AsInteger := Integer(AutoIncValue);

     SetAutoIncValue(AutoIncValue);

     <SetOtherFieldValues>

     Post;

   except

     Cancel;

     raise;

   end;

   Commit;

 except

   Rollback;

   raise;

 end;

end;