You can use views to focus, simplify, and customize each user’s perception of the database; they also provide an easy-to-use security measure. Views can also be helpful when changes have been made to the structure of a database, but users prefer to work with the structure of the database they are accustomed to.
You can use views to:
Focus on the data that interests them and on the tasks for which they are responsible. Data that is not of interest to a user can be left out of the view.
Define frequently used joins, projections, and selections as views so that users do not have to specify all the conditions and qualifications each time an operation is performed on that data.
Display different data for different users, even when they are using the same data at the same time. This advantage is particularly important when users of many different interests and skill levels share the same database.