Chapter 2: Entity-Relationship Model Basic Concepts Constraints Keys Design Issues E-R Diagram Weak Entity Sets Extended E-R Features Design of an E-R Database Schema Reduction of an E-R Schema to Tables 标 Database System Concepts 2.1 @Silberschatz, Korth and SudarshanDatabase System Concepts 2.1 ©Silberschatz, Korth and Sudarshan Chapter 2: Entity-Relationship Model Basic Concepts Constraints Keys Design Issues E-R Diagram Weak Entity Sets Extended E-R Features Design of an E-R Database Schema Reduction of an E-R Schema to Tables