Views is a technique that the DBMS uses in order to restrict access of certain parts of the database to people based on their role.
For example at school, teachers can see timetable details of students, but cannot access financial details which are stored on the same database.
The DBMS may control this by creating virtual tables, based on user log in. These virtual tables do not affect the underlying data in any way but they can control what users can do.
For example a teacher may be able to delete a student out of their class list table but that student will not be deleted from the entire database. The school enrolment officer, however, will be able to delete the entire record for the same student if need be.
