There is a major difference between intension and extension. Let’s discuss it one by one.  Intension – Intension, also commonly known as the database schema, is used to define the description of the database. It is set during the database design, and it rarely changes afterwards.  Extension – Extension is a measure of the number of tuples that exist in the database at a given point in time. A database extension also known as database snapshot. It changes its value whenever tuples in a database are created, updated, and deleted.