Most web applications use a database to store their data. The databases frequently hold sensitive data. When creating your web application, consider what data is going to be in the database and how secure you need to make that data. You also need to understand the security mechanisms provided by the manufacturer of the database and decide whether they are sufficient for your needs. If the mechanisms are not sufficient, you can use other security techniques to improve the security of the database, such as encrypting sensitive data before writing it to the database.