Database Systems. A Practical Approach to Design, Implementation, and Management

The history of database research over the past 30 years is one of exceptional productivity that has led to the database system becoming arguably the most important development in the field of software engineering. The database is now the underlying framework of the information system and has fundamentally changed the way many organizations operate. In particular, the developments in this technology over the last few years have produced systems that are more powerful and more intuitive to use. This development has resulted in increasing availability of database systems for a wider variety of users. Unfortunately, the apparent simplicity of these systems has led to users creating databases and applications without the necessary knowledge to produce an effective and efficient system. And so the “software crisis” or, as it is sometimes referred to, the “software depression” continues. The original stimulus for this book came from the authors’ work in industry, providing consultancy on database design for new software systems or, as often as not, resolving inadequacies with existing systems. In addition, the authors’ move to academia brought similar problems from different users—students. The objectives of this book, therefore, are to provide a textbook that introduces the theory behind databases as clearly as possible and, in particular, to provide a methodology for database design that can be used by both technical and nontechnical readers.

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Database systems

A Practical Approach to Design, Implementation, and Management

SIXth EDItIon GlobAl EDItIon

Database systems

A Practical Approach to Design, Implementation, and Management

SIXth EDItIon GlobAl EDItIon

University of the west of sCotlanD

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Thomas M Connolly

To my past, present, and future students at UWS

Carolyn E Begg

Preface 35

Chapter 3 Database Architectures and the Web 105

Chapter 5 Relational Algebra and Relational Calculus 167

Chapter 10 Database System Development Lifecycle 345

Chapter 11 Database Analysis and the DreamHome Case Study 375

Chapter 13 Enhanced Entity–Relationship Modeling 433

Chapter 16 Methodology—Conceptual Database Design 503

Chapter 17 Methodology—Logical Database Design

Brief Contents

7

Chapter 18 Methodology—Physical Database Design

Chapter 19 Methodology—Monitoring and Tuning

Chapter 21 Professional, Legal, and Ethical Issues in Data

Chapter 24 Distributed DBMSs—Concepts and Design 785

Chapter 25 Distributed DBMSs—Advanced Concepts 831

Chapter 26 Replication and Mobile Databases 875

Chapter 27 Object-Oriented DBMSs—Concepts and Design 941

Chapter 28 Object-Oriented DBMSs—Standards and Systems 995

Brief Contents | 9

A Users’ Requirements Specification for DreamHome Case Study A-1

D Summary of the Database Design Methodology

E Introduction to Pyrrho: A Lightweight RDBMS E-1

F File Organizations and Indexes (Online) F-1

H Commercial DBMSs: Access® and Oracle® (Online) H-1

J Estimating Disk Space Requirements (Online) J-1

K Introduction to Object-Oriented Concepts (Online) K-1

References R-1

Index IN-1

1.4.1 Data and Database Administrators 69

2.1 The Three-Level ANSI-SPARC Architecture 84

2.2.2 The Data Manipulation Language (DML) 902.2.3 Fourth-Generation Languages (4GLs) 922.3 Data Models and Conceptual Modeling 93

Part 2 The Relational Model and Languages 147

4.1 Brief History of the Relational Model 150

6.3 Data Manipulation 196

6.3.2 Sorting Results (ORDER BY Clause) 2056.3.3 Using the SQL Aggregate Functions 2076.3.4 Grouping Results (GROUP BY Clause) 209

6.3.9 Combining Result Tables (UNION, INTERSECT,

7.3.5 Creating an Index (CREATE INDEX) 2507.3.6 Removing an Index (DROP INDEX) 250

7.4.7 Advantages and Disadvantages of Views 258

Contents | 15

7.5.1 Immediate and Deferred Integrity Constraints 262

7.6.1 Granting Privileges to Other Users (GRANT) 2647.6.2 Revoking Privileges from Users (REVOKE) 265

9.3 Storing Objects in a Relational Database 302

9.3.2 Accessing Objects in the Relational Database 3049.4 Introduction to Object-Relational Database Systems 305

9.6 Object-Oriented Extensions in Oracle 331

Part 3 Database Analysis and Design 343

10.2 The Database System Development Lifecycle 347

11.1 When Are Fact-Finding Techniques Used? 376

11.4 Using Fact-Finding Techniques: A Worked -Example 381

11.4.1 The DreamHome Case Study—An Overview of the

11.4.2 The DreamHome Case Study—Database Planning 386

11.4.3 The DreamHome Case Study—System Definition 392

11.4.4 The DreamHome Case Study—Requirements

11.4.5 The DreamHome Case Study—Database Design 401

12.6 Structural Constraints 41912.6.1 One-to-One (1:1) Relationships 42012.6.2 One-to-Many (1:*) Relationships 42112.6.3 Many-to-Many (*:*) Relationships 42212.6.4 Multiplicity for Complex Relationships 42312.6.5 Cardinality and Participation Constraints 424

Generalization to Model the Branch View of the

14.2 How Normalization Supports Database Design 45314.3 Data Redundancy and Update Anomalies 454

14.6 First Normal Form (1NF) 466

14.9 General Definitions of 2NF and 3NF 473

15.1.1 Inference Rules for Functional Dependencies 48215.1.2 Minimal Sets of Functional Dependencies 484

15.3 Review of Normalization Up to BCNF440

15.4.2 Definition of Fourth Normal Form 495

16.1 Introduction to the Database Design Methodology 50416.1.1 What Is a Design Methodology? 50416.1.2 Conceptual, Logical, and Physical Database Design 50516.1.3 Critical Success Factors in Database Design 50516.2 Overview of the Database Design Methodology 50616.3 Conceptual Database Design Methodology 508 Step 1: Build Conceptual Data Model 508

Contents | 19

Chapter 17 Methodology—Logical Database Design

17.1 Logical Database Design Methodology for

Chapter 18 Methodology—Physical Database Design

18.1 Comparison of Logical and Physical Database Design 56218.2 Overview of the Physical Database Design Methodology 56318.3 The Physical Database Design Methodology for

Step 3: Translate Logical Data Model for Target DBMS 564Step 4: Design File Organizations and Indexes 569

Chapter 19 Methodology—Monitoring and Tuning

19.1 Denormalizing and Introducing Controlled Redundancy 585 Step 7: Consider the Introduction of Controlled

Part 5 Selected Database Issues 605

21.2.6 Access to Information Laws 65221.2.7 International Banking—Basel II Accords 65421.3 Establishing a Culture of Legal and Ethical

21.3.1 Developing an Organization-Wide Policy for Legal

21.3.2 Professional Organizations and Codes of Ethics 65621.3.3 Developing an Organization-Wide Policy for Legal

22.3.5 Recovery in a Distributed DBMS 709

22.5 Concurrency Control and Recovery in Oracle 716

22.5.2 Multiversion Read Consistency 717

(T = R  S, T = R  S, T = R – S) 75923.5 Enumeration of Alternative Execution Strategies 760

23.5.3 Physical Operators and Execution Strategies 762

23.5.7 Alternative Approaches to Query Optimization 76723.5.8 Distributed Query Optimization 768

23.7.1 Rule-Based and Cost-Based Optimization 772

Part 6 Distributed DBMSs and Replication 783

25.1 Distributed Transaction Management 832

25.4.1 Failures in a Distributed Environment 841

25.5 The X/Open Distributed Transaction Processing Model 854

26.3.5 Update Anywhere with Uniform

26.3.6 SI and Uniform Total Order Broadcast Replication 907

Contents | 25

27.2 Introduction to OODBMSs 94527.2.1 Definition of Object-Oriented DBMSs 945

27.2.3 Persistent Programming Languages 95127.2.4 Alternative Strategies for Developing an OODBMS 953

27.7.1 Comparison of Object-Oriented Data Modeling

27.7.2 Relationships and Referential Integrity 980

27.8 Object-Oriented Analysis and Design with UML 984

27.8.2 Usage of UML in the Methodology

28.1.2 The Common Object Request Broker Architecture 999

28.2.3 The Object Definition Language 1018

28.2.5 Other Parts of the ODMG Standard 102728.2.6 Mapping the Conceptual Design to a Logical

Part 8 The Web and DBMSs 1045

29.1 Introduction to the Internet and the Web 1048

29.2.4 Static and Dynamic Web Pages 1058

29.4.1 Passing Information to a CGI Script 106929.4.2 Advantages and Disadvantages of CGI 1071

Contents | 27

29.7.3 Comparison of JDBC and SQLJ 108429.7.4 Container-Managed Persistence (CMP) 1085

29.8.2 Active Server Pages and ActiveX Data Objects 1109

30.3.5 XPointer (XML Pointer Language) 114930.3.6 XLink (XML Linking Language) 1150

30.3.8 Simple Object Access Protocol (SOAP) 115130.3.9 Web Services Description Language (WSDL) 1152

30.3.10 Universal Discovery, Description, and

30.5.1 Extending Lore and Lorel to Handle XML 1167

30.5.3 XQuery—A Query Language for XML 1169

30.5.5 XQuery 1.0 and XPath 2.0 Data Model (XDM) 1180

Part 9 Business Intelligence 1221

31.1.1 The Evolution of Data Warehousing 1224

31.1.3 Benefits of Data Warehousing 122631.1.4 Comparison of OLTP Systems

31.1.5 Problems of Data Warehousing 1228

31.3 Data Warehousing Tools and Technologies 123531.3.1 Extraction, Transformation, and Loading (ETL) 1236

31.3.4 Administration and Management Tools 1242

31.4.1 Reasons for Creating a Data Mart 124331.5 Data Warehousing and Temporal Databases 124331.5.1 Temporal Extensions to the SQL Standard 1246

31.6.1 Warehouse Features in Oracle 11g 125131.6.2 Oracle Support for Temporal Data 1252

32.1 Designing a Data Warehouse Database 125832.2 Data Warehouse Development Methodologies 125832.3 Kimball’s Business Dimensional Lifecycle 1260

32.4.1 Comparison of DM and ER models 126432.5 The Dimensional Modeling Stage of Kimball’s

32.5.1 Create a High-Level Dimensional Model

32.5.2 Identify All Dimension Attributes for the

32.6 Data Warehouse Development Issues 127332.7 Data Warehousing Design Using Oracle 127432.7.1 Oracle Warehouse Builder Components 127432.7.2 Using Oracle Warehouse Builder 1275

32.7.3 Warehouse Builder Features in Oracle 11g 1279

33.2 OLAP Applications 1287

33.3.1 Alternative Multidimensional Data Representations 128933.3.2 Dimensional Hierarchy 129133.3.3 Multidimensional Operations 1293

33.4.2 OLAP Server—Implementation Issues 1295

33.5 OLAP Extensions to the SQL Standard 130033.5.1 Extended Grouping Capabilities 1300

33.6.2 Platform for Business Intelligence

Contents | 31

34.6.2 Enabling Data Mining Applications 1325

34.6.4 Oracle Data Mining Environment 1326

34.6.5 Data Mining Features in Oracle 11g 1327

A Users’ Requirements Specification

A.1.2 Transaction Requirements (Sample) A-3

A.2.2 Transaction Requirements (Sample) A-5

B.1 The University Accommodation Office Case Study B-1

B.3.2 Transaction Requirements (Sample) B-12

C.1 ER Modeling Using the Chen Notation C-1C.2 ER Modeling Using the Crow’s Feet Notation C-1

D Summary of the Database Design Methodology

Step 3: Translate Logical Data Model for Target DBMS D-5Step 4: Design File Organizations and Indexes D-5

Step 5: Design User Views D-5

Step 7: Consider the Introduction of Controlled

Step 8: Monitor and Tune the Operational System D-6

H Commercial DBMSs: Access and Oracle

J Estimating Disk Space Requirements

K Introduction to Object-Oriented Concepts

References R-1

Index IN-1

Contents | 33

The history of database research over the past 30 years is one of exceptional productivity that has led to the database system becoming arguably the most important development in the field of software engineering The database is now the underlying framework of the information system and has fundamentally changed the way many organizations operate In particular, the developments

in this technology over the last few years have produced systems that are more powerful and more intuitive to use This development has resulted in increas-ing availability of database systems for a wider variety of users Unfortunately, the apparent simplicity of these systems has led to users creating databases and applications without the necessary knowledge to produce an effective and effi-cient system And so the “software crisis” or, as it is sometimes referred to, the

“software depression” continues

The original stimulus for this book came from the authors’ work in industry, providing consultancy on database design for new software systems or, as often as not, resolving inadequacies with existing systems In addition, the authors’ move to academia brought similar problems from different users—students The objectives

of this book, therefore, are to provide a textbook that introduces the theory behind databases as clearly as possible and, in particular, to provide a methodology for database design that can be used by both technical and nontechnical readers

The methodology presented in this book for relational Database Management Systems (DBMSs)—the predominant system for business applications at present—has been tried and tested over the years in both industrial and academic environments It consists of three main phases: conceptual, logical, and physical database design The first phase starts with the production of a conceptual data model that is independent of all physical considerations This model is then refined

in the second phase into a logical data model by removing constructs that cannot

be represented in relational systems In the third phase, the logical data model is translated into a physical design for the target DBMS The physical design phase considers the storage structures and access methods required for efficient and secure access to the database on secondary storage

Preface

35

The methodology in each phase is presented as a series of steps For the inexperienced designer, it is expected that the steps will be followed in the order described, and guidelines are provided throughout to help with this process For the experienced designer, the methodology can be less prescriptive, acting more as

a framework or checklist To help the reader use the methodology and understand the important issues, the methodology has been described using a realistic worked

example, based on an integrated case study, DreamHome In addition, three

additional case studies are provided in Appendix B to allow readers to try out the methodology for themselves

UML (Unified Modeling Language)

Increasingly, companies are standardizing the way in which they model data

by selecting a particular approach to data modeling and using it throughout their database development projects A popular high-level data model used in conceptual/logical database design, and the one we use in this book, is based

on the concepts of the Entity–Relationship (ER) model Currently there is no standard notation for an ER model Most books that cover database design for relational DBMSs tend to use one of two conventional notations:

• Chen’s notation, consisting of rectangles representing entities and diamonds representing relationships, with lines linking the rectangles and diamonds; or

• Crow’s Feet notation, again consisting of rectangles representing entities and lines between entities representing relationships, with a crow’s foot at one end of

a line representing a one-to-many relationship

Both notations are well supported by current Computer-Aided Software Engineering (CASE) tools However, they can be quite cumbersome to use and a bit difficult to explain In previous editions, we used Chen’s notation However, following an extensive questionnaire carried out by Pearson Education, there was a general consensus that the notation should be changed to the latest object-oriented modeling language, called UML (Unified Modeling Language) UML

is a notation that combines elements from the three major strands of oriented design: Rumbaugh’s OMT modeling, Booch’s Object-Oriented Analysis and Design, and Jacobson’s Objectory

object-There are three primary reasons for adopting a different notation: (1) UML

is becoming an industry standard; for example, the Object Management Group (OMG) has adopted UML as the standard notation for object methods; (2) UML

is arguably clearer and easier to use; and (3) UML is now being adopted within academia for teaching object-oriented analysis and design, and using UML in database modules provides more synergy Therefore, in this edition we have ad-opted the class diagram notation from UML We believe that you will find this notation easier to understand and use

Preface | 37 What’s New in the Sixth Edition

• Extended chapter on database architectures and the Web, covering cloud computing

• Updated chapter on professional, legal, and ethical issues in IT and databases

• New section on data warehousing and temporal databases

• New review questions and exercises at the end of chapters

• Updated treatment to cover the latest version of the SQL standard, which was

released in late 2011 (SQL:2011)

• Revised chapter on replication and mobile databases

• Updated chapters on Web-DBMS integration and XML

• Coverage updated to Oracle 11g.

Intended Audience

This book is intended as a textbook for a one- or two-semester course in database

management or database design in an introductory undergraduate, graduate, or

advanced undergraduate course Such courses are usually required in an

infor-mation systems, business IT, or computer science curriculum

The book is also intended as a reference book for IT professionals, such as tems analysts or designers, application programmers, systems programmers, da-

sys-tabase practitioners, and for independent self-teachers Owing to the widespread

use of database systems nowadays, these professionals could come from any type

of company that requires a database

It would be helpful for students to have a good background in the file organization and data structures concepts covered in Appendix F before

covering the material in Chapter 18 on physical database design and Chapter 23

on query processing This background ideally will have been obtained from

a prior course If this is not possible, then the material in Appendix F can be

presented near the beginning of the database course, immediately following

(2) An easy-to-use, step-by-step methodology for physical database design, covering the mapping of the logical design to a physical implementation, the selection

of file organizations and indexes appropriate for the applications, and when to introduce controlled redundancy Again, there is an integrated case study show-ing how to use the methodology.

(3) Separate chapters showing how database design fits into the overall database systems development lifecycle, how fact-finding techniques can be used to identify the system requirements, and how UML fits into the methodology

(4) A clear and easy-to-understand presentation, with definitions clearly highlighted, chapter objectives clearly stated, and chapters summarized

Numerous examples and diagrams are provided throughout each chapter to illustrate the concepts There is a realistic case study integrated throughout the book and additional case studies that can be used as student projects

(5) Extensive treatment of the latest formal and de facto standards: Structured Query Language (SQL), Query-By-Example (QBE), and the Object Data Management Group (ODMG) standard for object-oriented databases

(6) Three tutorial-style chapters on the SQL standard, covering both interactive and embedded SQL

(7) A chapter on legal, professional and ethical issues related to IT and databases

(8) Comprehensive coverage of the concepts and issues relating to distributed DBMSs and replication servers

(9) Comprehensive introduction to the concepts and issues relating to object-based DBMSs including a review of the ODMG standard and a tutorial on the object management facilities within the latest release of the SQL standard, SQL:2011

(10) Extensive treatment of the Web as a platform for database applications with many code samples of accessing databases on the Web In particular, we cover persistence through Container-Managed Persistence (CMP), Java Data Ob-jects (JDO), Java Persistence API (JPA), JDBC, SQLJ, ActiveX Data Objects (ADO), ADO.NET, and Oracle PL/SQL Pages (PSP)

(11) An introduction to semistructured data and its relationship to XML and tensive coverage of XML and its related technologies In particular, we cover XML Schema, XQuery, and the XQuery Data Model and Formal Semantics

ex-We also cover the integration of XML into databases and examine the sions added to SQL:2008 and SQL:2011 to enable the publication of XML

exten-(12) Comprehensive introduction to data warehousing, Online Analytical ing (OLAP), and data mining

Process-(13) Comprehensive introduction to dimensionality modeling for designing a data warehouse database An integrated case study is used to demonstrate a meth-odology for data warehouse database design

(14) Coverage of DBMS system implementation concepts, including concurrency and recovery control, security, and query processing and query optimization

Pedagogy

Before starting to write any material for this book, one of the objectives was to produce a textbook that would be easy for the readers to follow and understand,