Chapter 5. The Relational Data Model
Once you have a completed ER diagram, you can translate that conceptual logical schema into the formal data model required by your DBMS. Today, most new database installations are based on the relational data model. We call databases that adhere to that model relational databases.
Note: The older data models that are described in Appendix A
are still in use in many legacy database systems. However, it is extremely rare to find a business creating a new one. On the other hand, the object-oriented data model is still quite current, and although it has not replaced the relational data model and does not appear to be doing so, some new installations use either object-oriented or a combination of relational and object-oriented. ...