Hi,
Welcome in the world of databases ;)
So first it will be good If you can create a table the main object of the databases... They stock your information...
The trick here is how to create your tables, so that they gat minimum place phisically and are the most possible informative...
And remember there is a 3 operations with data:
APPEND, UPDATE AND DELETE
So be carefull what heppans with your data when the user uses one of this Actions...
There is databses in which users can only add records without possibility to delete and update... And there is the full history of the events without loss...
There is a lot of concepts in the databases :)
:)
Cheers
:)