本书由美国斯坦福大学知名计算机科学家Jeffrey Ullman和Jennifer Widom合作编写。书中介绍了核心DBMS概念、理论和模型,描述了如何使用抽象语言和SQL查询与更新DBMS。在介绍了SQL扩展内容(包括嵌入式SQL程序设计和对象关系特征)后,又介绍了使用XML的系统。设计语言包括XML模式,查询语言包括XPath和XQuery。
本书特色
全面改版的组织结构。
UML数据库模型的新内容。
包括3NF综合算法在内的操作依赖新算法的引入。
更多的3NF,包括3NF综合算法。
扩展的SQL触发讨论。
新增的索引选择和物化视图。
新增的三层体系结构。
新增的PHP。
新增的OLAP和SQL立方体操作符介绍。
扩展的XML内容,包括XML模式、XPath、XQuery和XSLT。

4.6.3Using Null Values to Combine Relations
There is one more approach to representing information ab out a hier ar chy ofentity sets.If we axe allowed to use NULL(the null value aS in SQL)as avalue in t uples,we can h andle a hier archy of entity sets with a single relationThis relation has all the att rib utes b elonging to any entity set of the hierarchy.An entity is then represented by a single tup le.This tuple has NuLL in eachattribute that is not defined for that entity.Example 4.33:If we applied this approach to the diagram of Fig.4.3 1,wewould create a single relation whose schema iS:
Movie(title,year,length,genre,weapon)Those movies t hat are not mur der mysteries would have NULL in the weapon comp onent of their tuple.It would also be necessary to have a relation Voicesto connect those movies that are cartoons to t he starts performing the voices,as in Example.

The Worlds of Database Systems
1.1The Evolution of Database Systems
1.1.1Early Database Management Systems
1.1.2Relational Database Systems
1.1.3Smaller and Smaller Systems
1.1.4Bigger and Bigger Systems
1.1.5Information Integration
1.2Overview of a Database Management System
1.2.1Data-Definition Language Commands
1.2.2Overview of Query Processing
1.2.3Storage and Buffer Management
1.2.4Transaction Processing
1.2.5The Query Processor
1.3Outline of Database-System Studies
1.4References for Chapter 1
IRelational Database Modeling
2The Relational Model of Data
2.1An Overview of Data Models
2.1.1What is a Data Model?
2.1.2Important Data Models
2.1.3The Relational Model in Brief
2.1.4The Semistructured Model in Brief
2.1.5Other Data Models
2.1.6Comparison of Modeling Approaches
2.2Basics of the Relational Model
2.2.1Attributes
2.2.2Schemas
2.2.3Tuples
2.2.4Domains
2.2.5Equivalent Representations of a Relation
2.2.6Relation Instances
2.2.7Keys of Relations
2.2.8An Example Database Schema
2.2.9Exercises for Section 2.2
2.3Defining a Relation Schema in SQL
2.3.1Relations in SQL
2.3.2Data Types
2.3.3Simple Table Declarations
2.3.4Modifying Relation Schemas
2.3.5Default Values
2.3.6Declaring Keys
2.3.7Exercises for Section 2.3
2.4An Algebraic Query Language
2.4.1Why Do We Need a Special Query Language?
2.4.2 What is an Algebra?
2.4.3Overview of Relational Algebra
2.4.4Set Operations on Relations
2.4.5Projection
2.4.6Selection
2.4.7Cartesian Product
2.4.8Natural Joins
2.4.9Theta-Joins
2.4.10 Combining Operations to Form Queries
2.4.11 Naming and Renaming
2.4.12 Relationships Among Operations
2.4.13 A Linear Notation for Algebraic Expressions
2.4.14 Exercises for Section 2.4
2.5Constraints on Relations
2.5.1Relational Algebra as a Constraint Language
2.5.2Referential Integrity Constraints
2.5.3Key Constraints
2.5.4Additional Constraint Examples
2.5.5Exercises for Section 2.5
2.6Summary of Chapter 2
2.7References for Chapter 2
Design Theory for Relational Databases
3.1Functional Dependencies
3.1.1Definition of Functional Dependency
3.1.2Keys of Relations
3.1.3Superkeys
3.1.4Exercises for Section 3.1
3.2Rules About Functional Dependencies
3.2.1Reasoning About Functional Dependencies
3.2.2The Splitting/Combining Rule
3.2.3 nivial Functional Dependencies
3.2.4 Computing the Closure of Attributes
3.2.5 Why the Closure Algorithm Works
3.2.6 The Transitive Rule
3.2.7 Closing Sets ofFunctional Dependencies
3.2.8 Projecting Functional Dependencies
3.2.9 Exercises for Section 3.2
3.3 Design of Relational Database Schema
3.3.1Anomalies
3.3.2 Decomposing Relations
3.3.3 Boyce-Codd Normal Form
3.3.4 Decomposition into BCNF
3.3.5 Exercises for Section 3.3
3.4 Decomposition:The Good,Bad,and Ugly
3.4.1Recovering Information from a Decomposition
3.4.2 The Chase Test for Lossless Join
3.4.3Why the Chase works
3.4.4 Dependency Preservation
3.4.5 Exercises for Section 3.4
3.5 Third Normal Form
3.5.1 Definition of Third Normal Form
3.5.2The Synthesis Algorithm for 3NF Schemas
3.5.3 Why the 3NF Synthesis Algorithm Works
3.5.4 Exercises for Section 3.5
3.6 Multivalued Dependencies
3.6.1Attribute Independence and Its Consequent Redundancy
3.6.2 Definition ofMultivalued Dependencies
3.6.3Reasoning About Multivalued Dependencies
3.6.4 F0urth Normal Form
3.6.5 Decomposition into Fourth Normal Form
3.6.6Relationships Among Normal Forms
3.6.7 Exercises for Section 3.6
3.7 An Algorithm for Discovering MVD'S
3.7.1 The Closure and the Chase
3.7.2Extending the Chase to MVD's
3.7.3Why the Chase W10rks for MVD'S
3.7.4 Projecting MVD'S
3.7.5 Exercises for Section 3.7
3.8 Summary of Chapter 3
3.9 References for Chapter 3
4 High-Level Database M0dels
5 Algebraic and Logical Query Languages
6 The Database Language SQL
7 Constraints and Triggers
8 Views and Indexes
9 SQL in a Server Environment
10 Advanced Topics in Relational Databases
Ⅲ Modeling and Programming for semistructured Data
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