Hello everybody

I have a MySQL InnoDB database and am using Visual Basic 6 as a front end to access the tables via the ADO data access framework. However, the database can be accessed by users of varying rights. This brings forth the problem of how my application will handle attempted rights to a table. Do I have to do the validation in my code before attempting to write or can I leave that job to the DBMS and get informed by an error code it returns?
What is the best approach?