I've ran across this several times when our databases that do not have a rising column or incrementing ID (Primary Key). Our solution was to change these to batch and query records between datetime and set the DB connect to query to the record time.. example if i grab the last 15 mins of records then I would set the DB connect to query every 15 mins.
The rising column has to be numeric. There maybe some better answers out there. This has always worked for us.