>My users download an application from a website. If i make changes to the data structure of the tables, how can i ensure that the table structure that they previously downloaded is updated as well....
>
>Need a program that will:
>1. Check the data structure of tables within a dbc
>2. If it finds for instance character field was changed to at numeric field, then update....

One way of doing this is to maintain database versioning. When the application opens the database it checks for the db's version and updates it accordingly through a designated procedure. This procedure grows as changes in database occurs, and it can be "cascaded" (that is, if application v3 founds a database v1 then issue the v1 - v2 upgrade, then recheck to the v2 - v3 upgrade...). It's not as robust as a comprehensive general check-up, particulary if you need to be sure of changes occurred by action of foreign agents, but it's right at hand.