To decide which information you should store in the database, you have to understand the purpose of the database and how it will be used.
Involving the End User in the Process
The best way to do this is to talk to the people who will be using it. Involving the end user in this process, as early as possible, helps eliminate problems that can stem from misunderstandings about the purpose of the database. Interviewing the end users will help you understand the tasks they expect the system to perform. Based on this understanding, you can determine the kind of data and thereby the kind of tables, forms, and reports that are necessary for completing these tasks. This will often be the most difficult part of the design process as well as the most important. The usefulness of the entire application depends on whether the tables, forms, and reports have been designed correctly.
Your discussions with the end users will give you insight into the tasks they need to perform. You will then know what information the forms and reports should provide. This does not, however, necessarily tell you how the tables should be designed.