relational data model

Data Independence in SQL and DBMSs

An important advantage of database management systems is Data Independence. Data Independence refers to the insulation from applications programs from changes in the way the data is structured and stored. Levels of Abstraction in a DBMS graph TD F(fa:fa-table View 1)---E G(fa:fa-table View 2)---E H(fa:fa-table View 3)---E["fa:fa-database Conceptual Schema"] E---A["fa:fa-server Physical Schema"] A---B["fa:fa-HDD-o Disk"] Logical Independence If the structure of the data changes, applications and users can be insulated from this changes thanks to external schemas (in SQL, views).