I already answered to you in my first answer. If you don't ask a more precise question, we can't help because forum goal is not to answer basic questions.
As I am a nice person, I give you an overview:
That's a simple and complex topic, and you have to be trained (read the documentation as I said, forum is not here to repeat the documentation).
In short, you have to do the updates at the latest moment (when user saves, after the checks have been done), and you end them with COMMIT WORK (that calls update function modules, see below, then issues a database commit). If a dump occurs at any time, SAP automatically issues a ROLLBACK WORK that undo all updates done since the previous COMMIT. You may issue it programmatically if you need to handle errors between updates.
If you have lots of updates or can't do it at the latest moment, you update database using the update task: you create function modules by setting the "update" flag in the properties tab, and you call them using CALL FUNCTION ... IN UPDATE TASK.
Some abap statements issue implicitly a database commit, so you must not use them between updates. Here are these statements: [Database Commit|http://sandraros.free.fr/abap_docu.htm?url=ABENDB_COMMIT.htm]
And here is [COMMIT WORK documentation|http://sandraros.free.fr/abap_docu.htm?url=ABAPCOMMIT.htm]
There are lots of other concepts, you understand that I can't explain here, so refer to the doc, or attend a training.
Bluesky
