Database Systems: Design, Implementation, and Management Tenth Edition Chapter 4 Entity Relationship (ER) Modeling.

Slides:



Advertisements
Similar presentations
Chapter # 4 BIS Database Systems
Advertisements

Chapter 5 Normalization of Database Tables
Entity Relationship (E-R) Modeling Hachim Haddouti
Entity Relationship (ER) Modeling
Chapter 4 Entity Relationship (E-R) Modeling
Entity Relationship (ER) Modeling
Chapter 4 Entity Relationship (ER) Modeling
4 1 Chapter 4 Entity Relationship (ER) Modeling Database Systems: Design, Implementation, and Management, Sixth Edition, Rob and Coronel.
Database Systems: Design, Implementation, and Management Eighth Edition Chapter 4 Entity Relationship (ER) Modeling.
Chapter 4 Entity Relationship (E-R) Modeling
Entity Relationship (ER) Modeling
Entity Relationship (ER) Modeling
The Relational Database Model
Database Systems: Design, Implementation, and Management Tenth Edition
Entity-Relation Modeling Hun Myoung Park, Ph.D., Public Management and Policy Analysis Program Graduate School of International Relations International.
Entity Relationship (E-R) Modeling
1 © Prentice Hall, 2002 Chapter 5: Logical Database Design and the Relational Model Modern Database Management 6 th Edition Jeffrey A. Hoffer, Mary B.
Chapter 4 ENTITY-RELATIONSHIP MODELLING.
Database Systems: Design, Implementation, & Management, 5 th Edition, Rob & Coronel 1 Data Models: Degrees of Data Abstraction l Modified ANSI/SPARC Framework.
Chapter 5 Normalization of Database Tables
Chapter 4 Entity Relationship (ER) Modeling
Database Systems: Design, Implementation, and Management Tenth Edition
Chapter 4 Entity-Relationship modeling Transparencies © Pearson Education Limited 1995, 2005.
BTM 382 Database Management Chapter 4: Entity Relationship (ER) Modeling Chitu Okoli Associate Professor in Business Technology Management John Molson.
The Relational Database Model
Entity-Relationship modeling Transparencies
3 Chapter 3 Entity Relationship (E-R) Modeling Database Systems: Design, Implementation, and Management, Fifth Edition, Rob and Coronel.
Chapter 7 Data Modeling with Entity Relationship Diagrams Database Principles: Fundamentals of Design, Implementation, and Management Tenth Edition.
ITEC 3220M Using and Designing Database Systems Instructor: Prof. Z.Yang Course Website: 3220m.htm
4 1 Chapter 4 Entity Relationship (ER) Modeling Database Systems: Design, Implementation, and Management, Seventh Edition, Rob and Coronel.
Chapter 5 Entity Relationship (ER) Modelling
4 1 Chapter 4 Entity Relationship (ER) Modeling Database Systems: Design, Implementation, and Management, Sixth Edition, Rob and Coronel.
Database Systems: Design, Implementation, and Management Tenth Edition
BIS Database Systems School of Management, Business Information Systems, Assumption University A.Thanop Somprasong Chapter # 5 Normalization of Database.
© Pearson Education Limited, Chapter 7 Entity-Relationship modeling Transparencies.
Database Systems: Design, Implementation, and Management Eighth Edition Chapter 4 Entity Relationship (ER) Modeling.
Chapter 4 Entity Relationship (ER) Modeling.  ER model forms the basis of an ER diagram  ERD represents conceptual database as viewed by end user 
4 1 Database Systems: Design, Implementation, & Management, 7 th Edition, Rob & Coronel Relationship Degree Indicates number of entities or participants.
Database Design – Lecture 5 Conceptual Data Modeling – adding attributes.
3 & 4 1 Chapters 3 and 4 Drawing ERDs October 16, 2006 Week 3.
Chapter 9: Logical Database Design and the Relational Model (ERD Mapping)
1 A Demo of Logical Database Design. 2 Aim of the demo To develop an understanding of the logical view of data and the importance of the relational model.
3 & 4 1 Database Systems: Design, Implementation, & Management, 7 th Edition, Rob & Coronel Keys Consists of one or more attributes that determine other.
Database Design – Lecture 8
Database Systems: Design, Implementation, and Management Ninth Edition Chapter 4 Entity Relationship (ER) Modeling.
Copyright © 2011 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Chapter 7 Data Modeling Using the Entity- Relationship (ER) Model.
AL-MAAREFA COLLEGE FOR SCIENCE AND TECHNOLOGY INFO 232: DATABASE SYSTEMS CHAPTER 4 ENTITY RELATIONSHIP (ER) MODELING Instructor Ms. Arwa Binsaleh 1.
Database Systems: Design, Implementation, and Management Tenth Edition Chapter 3 The Relational Database Model.
Database Design – Lecture 4 Conceptual Data Modeling.
Database Design – Lecture 6 Moving to a Logical Model.
1 © Prentice Hall, 2002 ITD1312 Database Principles Chapter 4B: Logical Design for Relational Systems -- Transforming ER Diagrams into Relations Modern.
Logical Database Design and the Relational Model.
Department of Mathematics Computer and Information Science1 CS 351: Database Management Systems Christopher I. G. Lanclos Chapter 4.
Lecture # 14 Chapter # 5 The Relational Data Model and Relational Database Constraints Database Systems.
TMC2034 Database Concept and Design
Chen’s Type Guidance.
Entity Relationship (E-R) Modeling
Entity Relationship (E-R) Modeling
Chapter 5: Logical Database Design and the Relational Model
Tables and Their Characteristics
Database Design – Lecture 4
Database Systems: Design, Implementation, and Management Tenth Edition
Chapter 4 Entity Relationship (ER) Modeling
Database Systems: Design, Implementation, and Management Tenth Edition
Review of Week 1 Database DBMS File systems vs. database systems
Chapter 4 Entity Relationship (ER) Modeling
Entity Relationship (ER) Modeling
Review of Week 3 Relation Transforming ERD into Relations
Chapter # 4 Entity Relationship (ER) Modeling.
Presentation transcript:

Database Systems: Design, Implementation, and Management Tenth Edition Chapter 4 Entity Relationship (ER) Modeling

Connectivity and Cardinality Connectivity –Describes the relationship classification Cardinality –Expresses minimum and maximum number of entity occurrences associated with one occurrence of related entity Established by very concise statements known as business rules Database Systems, 10th Edition 2

3

Derived Attributes Derived attribute: value may be calculated from other attributes –Need not be physically stored within database Database Systems, 10th Edition 4

5

Existence Dependence Existence dependence –Entity exists in database only when it is associated with another related entity occurrence Existence independence –Entity can exist apart from one or more related entities –Sometimes such an entity is referred to as a strong or regular entity Database Systems, 10th Edition 6

Relationship Strength Weak (non-identifying) relationships –Exists if PK of related entity does not contain PK component of parent entity Strong (identifying) relationships –Exists when PK of related entity contains PK component of parent entity Database Systems, 10th Edition 7

8

9

Weak Entities Weak entity meets two conditions –Existence-dependent –Primary key partially or totally derived from parent entity in relationship Database designer determines whether an entity is weak based on business rules Database Systems, 10th Edition 10

Database Systems, 10th Edition 11

Database Systems, 10th Edition 12

Recursive Relationships Relationship can exist between occurrences of the same entity set Database Systems, 10th Edition 13

Recursive Relationships Relationship can exist between occurrences of the same entity set Database Systems, 10th Edition 14

Recursive Relationships Database Systems, 10th Edition 15

Database Systems, 10th Edition 16

1:1 Recursive Relationship Implementation EMPLOYEE_V1 table can yield anomalies if Anne Jones divorces Anton Shapiro –Two records must be updated, if only one is updated then we have inconsistent data –Nulls for those employees not married to other employees MARRIED_V1 eliminates nulls for employees not married to other employees but duplicate values are still possible (345,347) and (347,345) Third method requires collection of marriage date. Unless sending out congratulations each year, the information is unnecessary Theoretically possible to have more than two people in a marriage Database Systems, 10th Edition 17

Developing an ER Diagram Database design is an iterative process –Create detailed narrative of organization’s description of operations –Identify business rules based on description of operations –Identify main entities and relationships from business rules –Develop initial ERD –Identify attributes and primary keys that adequately describe entities –Revise and review ERD Database Systems, 10th Edition 18

Database Systems, 10th Edition 19

Database Systems, 10th Edition 20

Database Systems, 10th Edition 21

Database Systems, 10th Edition 22

Database Systems, 10th Edition 23

Database Systems, 10th Edition 24

Database Systems, 10th Edition 25

Database Systems, 10th Edition 26

Database Systems, 10th Edition 27

Database Systems, 10th Edition 28

Design Challenges Must conform to design standards –Minimize redundancies and avoid nulls when possible Processing Speed –High processing speeds are a top priority in today’s online world –Combine two tables into one which may be less elegant but faster data retrieval –Include derived attributes instead of computing them as needed Information Requirements –Complex information requirements might require additional entities and attributes within the design –May be worth sacrificing “clean” design and speed to ensure maximum information generation Database Systems, 10th Edition 29

Summary (cont’d.) Connectivities and cardinalities are based on business rules M:N relationship is valid at conceptual level –Must be mapped to a set of 1:M relationships ERDs may be based on many different ERMs UML class diagrams are used to represent the static data structures in a data model Database designers are often forced to make design compromises Database Systems, 10th Edition 30