Relational Database Systems Higher Information Systems.
Supporting Streaming Updates in an Active Data Warehouse Neoklis Polyzotis, Spiros Skiadopoulos, Panos Vassiliadis, Alkis Simitsis, Nils-Erik Frantzell.
Copyright © 2007 Ramez Elmasri and Shamkant B. Navathe Slide 5- 1.
Chapter 5 The Relational Data Model and Relational Database Constraints.