ch6

Chapter 6: Entity-Relationship Model Database System Concepts, 5th Ed . ©Silberschatz, Korth and Sudarshan See www.db-book.com for conditions on re-use

Chapter 6: Entity-Relationship Model ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],6.2 Database System Concepts - 5 th Edition, July 11, 2005

Modeling ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],6.3 Database System Concepts - 5 th Edition, July 11, 2005

Entity Sets customer and loan 6.4 Database System Concepts - 5 th Edition, July 11, 2005 customer_id customer_ customer_ customer_ loan_ amount name street city number

Relationship Sets ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],6.5 Database System Concepts - 5 th Edition, July 11, 2005

Relationship Set borrower 6.6 Database System Concepts - 5 th Edition, July 11, 2005

Relationship Sets (Cont.) ,[object Object],[object Object],6.7 Database System Concepts - 5 th Edition, July 11, 2005

Degree of a Relationship Set ,[object Object],[object Object],[object Object],[object Object],6.8 Database System Concepts - 5 th Edition, July 11, 2005 ,[object Object]

Attributes ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],6.9 Database System Concepts - 5 th Edition, July 11, 2005 Example: customer = ( customer_id, customer_name, customer_street, customer_city ) loan = ( loan_number, amount )

Composite Attributes 6.10 Database System Concepts - 5 th Edition, July 11, 2005

Mapping Cardinality Constraints ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],6.11 Database System Concepts - 5 th Edition, July 11, 2005

Mapping Cardinalities 6.12 Database System Concepts - 5 th Edition, July 11, 2005 One to one One to many Note: Some elements in A and B may not be mapped to any elements in the other set

Mapping Cardinalities 6.13 Database System Concepts - 5 th Edition, July 11, 2005 Many to one Many to many Note: Some elements in A and B may not be mapped to any elements in the other set

Keys ,[object Object],[object Object],[object Object],[object Object],[object Object],6.14 Database System Concepts - 5 th Edition, July 11, 2005

Keys for Relationship Sets ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],6.15 Database System Concepts - 5 th Edition, July 11, 2005

E-R Diagrams 6.16 Database System Concepts - 5 th Edition, July 11, 2005 ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

E-R Diagram With Composite, Multivalued, and Derived Attributes 6.17 Database System Concepts - 5 th Edition, July 11, 2005

Relationship Sets with Attributes 6.18 Database System Concepts - 5 th Edition, July 11, 2005

Roles ,[object Object],[object Object],[object Object],[object Object],6.19 Database System Concepts - 5 th Edition, July 11, 2005

Cardinality Constraints ,[object Object],[object Object],[object Object],[object Object],6.20 Database System Concepts - 5 th Edition, July 11, 2005

One-To-Many Relationship ,[object Object],6.21 Database System Concepts - 5 th Edition, July 11, 2005

Many-To-One Relationships ,[object Object],6.22 Database System Concepts - 5 th Edition, July 11, 2005

Many-To-Many Relationship ,[object Object],[object Object],6.23 Database System Concepts - 5 th Edition, July 11, 2005

Participation of an Entity Set in a Relationship Set 6.24 Database System Concepts - 5 th Edition, July 11, 2005 ,[object Object],[object Object],[object Object],[object Object],[object Object]

Alternative Notation for Cardinality Limits 6.25 Database System Concepts - 5 th Edition, July 11, 2005 ,[object Object]

E-R Diagram with a Ternary Relationship 6.26 Database System Concepts - 5 th Edition, July 11, 2005

Cardinality Constraints on Ternary Relationship ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],6.27 Database System Concepts - 5 th Edition, July 11, 2005

Design Issues ,[object Object],[object Object],[object Object],[object Object],6.28 Database System Concepts - 5 th Edition, July 11, 2005

Binary Vs. Non-Binary Relationships ,[object Object],[object Object],[object Object],[object Object],[object Object],6.29 Database System Concepts - 5 th Edition, July 11, 2005

Converting Non-Binary Relationships to Binary Form ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],6.30 Database System Concepts - 5 th Edition, July 11, 2005

Converting Non-Binary Relationships (Cont.) ,[object Object],[object Object],[object Object],[object Object],[object Object],6.31 Database System Concepts - 5 th Edition, July 11, 2005

Mapping Cardinalities affect ER Design 6.32 Database System Concepts - 5 th Edition, July 11, 2005 ,[object Object],[object Object]

How about doing an ER design interactively on the board? Suggest an application to be modeled. Database System Concepts, 5th Ed . ©Silberschatz, Korth and Sudarshan See www.db-book.com for conditions on re-use

Weak Entity Sets ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],6.34 Database System Concepts - 5 th Edition, July 11, 2005

Weak Entity Sets (Cont.) ,[object Object],[object Object],[object Object],[object Object],6.35 Database System Concepts - 5 th Edition, July 11, 2005

Weak Entity Sets (Cont.) ,[object Object],[object Object],6.36 Database System Concepts - 5 th Edition, July 11, 2005

More Weak Entity Set Examples ,[object Object],[object Object],[object Object],[object Object],6.37 Database System Concepts - 5 th Edition, July 11, 2005

Extended E-R Features: Specialization ,[object Object],[object Object],[object Object],[object Object],6.38 Database System Concepts - 5 th Edition, July 11, 2005

Specialization Example 6.39 Database System Concepts - 5 th Edition, July 11, 2005

Extended ER Features: Generalization ,[object Object],[object Object],[object Object],6.40 Database System Concepts - 5 th Edition, July 11, 2005

Specialization and Generalization (Cont.) ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],6.41 Database System Concepts - 5 th Edition, July 11, 2005

Design Constraints on a Specialization/Generalization ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],6.42 Database System Concepts - 5 th Edition, July 11, 2005

Design Constraints on a Specialization/Generalization (Cont.) ,[object Object],[object Object],[object Object],6.43 Database System Concepts - 5 th Edition, July 11, 2005

Aggregation 6.44 Database System Concepts - 5 th Edition, July 11, 2005 ,[object Object],[object Object]

Aggregation (Cont.) ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],6.45 Database System Concepts - 5 th Edition, July 11, 2005

E-R Diagram With Aggregation 6.46 Database System Concepts - 5 th Edition, July 11, 2005

E-R Design Decisions ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],6.47 Database System Concepts - 5 th Edition, July 11, 2005

E-R Diagram for a Banking Enterprise 6.48 Database System Concepts - 5 th Edition, July 11, 2005

How about doing another ER design interactively on the board? Database System Concepts, 5th Ed . ©Silberschatz, Korth and Sudarshan See www.db-book.com for conditions on re-use

Summary of Symbols Used in E-R Notation 6.50 Database System Concepts - 5 th Edition, July 11, 2005

Summary of Symbols (Cont.) 6.51 Database System Concepts - 5 th Edition, July 11, 2005

Reduction to Relation Schemas ,[object Object],[object Object],[object Object],[object Object],6.52 Database System Concepts - 5 th Edition, July 11, 2005

Representing Entity Sets as Schemas ,[object Object],[object Object],[object Object],[object Object],6.53 Database System Concepts - 5 th Edition, July 11, 2005

Representing Relationship Sets as Schemas ,[object Object],[object Object],[object Object],6.54 Database System Concepts - 5 th Edition, July 11, 2005

Redundancy of Schemas 6.55 Database System Concepts - 5 th Edition, July 11, 2005 ,[object Object],[object Object]

Redundancy of Schemas (Cont.) ,[object Object],[object Object],[object Object],[object Object],[object Object],6.56 Database System Concepts - 5 th Edition, July 11, 2005

Composite and Multivalued Attributes ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],6.57 Database System Concepts - 5 th Edition, July 11, 2005

Representing Specialization via Schemas ,[object Object],[object Object],[object Object],[object Object],6.58 Database System Concepts - 5 th Edition, July 11, 2005

Representing Specialization as Schemas (Cont.) ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],6.59 Database System Concepts - 5 th Edition, July 11, 2005

Schemas Corresponding to Aggregation 6.60 Database System Concepts - 5 th Edition, July 11, 2005 ,[object Object],[object Object],[object Object],[object Object]

Schemas Corresponding to Aggregation (Cont.) 6.61 Database System Concepts - 5 th Edition, July 11, 2005 ,[object Object],[object Object],[object Object]

UML ,[object Object],[object Object],[object Object],6.62 Database System Concepts - 5 th Edition, July 11, 2005

Summary of UML Class Diagram Notation 6.63 Database System Concepts - 5 th Edition, July 11, 2005

UML Class Diagrams (Cont.) ,[object Object],[object Object],[object Object],[object Object],[object Object],6.64 Database System Concepts - 5 th Edition, July 11, 2005

UML Class Diagram Notation (Cont.) 6.65 Database System Concepts - 5 th Edition, July 11, 2005 * Note reversal of position in cardinality constraint depiction * Generalization can use merged or separate arrows independent of disjoint/overlapping overlapping disjoint

UML Class Diagrams (Contd.) ,[object Object],[object Object],[object Object],[object Object],6.66 Database System Concepts - 5 th Edition, July 11, 2005

End of Chapter 2 Database System Concepts, 5th Ed . ©Silberschatz, Korth and Sudarshan See www.db-book.com for conditions on re-use

E-R Diagram for Exercise 2.10 6.68 Database System Concepts - 5 th Edition, July 11, 2005

Existence Dependencies ,[object Object],[object Object],[object Object],6.72 Database System Concepts - 5 th Edition, July 11, 2005 loan-payment payment loan If a loan entity is deleted, then all its associated payment entities must be deleted also.

Figure 6.8 6.73 Database System Concepts - 5 th Edition, July 11, 2005

Alternative E-R Notations Figure 6.24 6.82 Database System Concepts - 5 th Edition, July 11, 2005

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