Why should I select Oracle over MS Access?
Oracle, MS Access, and any other vendor's database package all have their advantages and disadvantages. Selecting one over another is really a case of weighing the advantages and disadvantages for your specific case. I'll give a brief description of the strengths and weaknesses of each of these two packages and then you can decide!
MS Access - This package is very cheap (it is part of Office Professional) and very easy to use. Most of the work in Access is done through wizards and GUI tools. One can quickly develop a small, single user database with this one. MS Access is not very good for a multi-user application. It is not very robust and does not have good multi-user transactional control. In addition, Access cannot handle large amounts of data. All of the data in the database is stored in a single file and that has its limitations.
Oracle - This package is not cheap at all. It is very complex and it can be difficult to administer. But its complexity makes it very robust. There is almost nothing that you cannot do in Oracle (unlike Access). Oracle is specifically designed for multi-user applications. In fact, thousands of users can access the same data without any problems due to Oracle's very good transactional control. But applications are not developed nearly as quickly. Oracle can also handle large amounts of data. In fact, Oracle 8i can handle up to 512 petabytes of data!
In the end, Oracle is a true Database Management System (DBMS) and Access is not. This does not mean that Access does not have its place. If I'm designing a quick database that only I'll use, I would do it in Access over Oracle. If I'm designing a robust, scalable application used throughout my enterprise with many users, then Oracle is my choice!