Tổng quan Một File hệ thống góc nhìn lịch sử so với một DBMS Ưu điểm của một DBMS Mô tả và lưu trữ dữ liệu trong một DBMS Mô hình quan hệ Mức độ trừu tượng trong một DBMS Truy vấn dữ liệu độc lập trong quản lý giao dịch DBMS đồng thời Thực hiện giao dịch Giao dịch không đầy đủ và hệ thống Crashes các điểm cần | Database Management Systems Second Edition Raghu Ramakrishnan Johannes Gehrke CONTENTS PREFACE xxii Part I BASICS 1 1 INTRODUCTION TO DATABASE SYSTEMS 3 Overview 4 A Historical Perspective 5 File Systems versus a DBMS 7 Advantages of a DBMS 8 Describing and Storing Data in a DBMS 9 The Relational Model 10 Levels of Abstraction in a DBMS 11 Data Independence 14 Queries in a DBMS 15 Transaction Management 15 Concurrent Execution of Transactions 16 Incomplete Transactions and System Crashes 17 Points to Note 18 Structure of a DBMS 18 People Who Deal with Databases 20 Points to Review 21 2 THE ENTITY-RELATIONSHIP MODEL 24 Overview of Database Design 24 Beyond the ER Model 25 Entities Attributes and Entity Sets 26 Relationships and Relationship Sets 27 Additional Features of the ER Model 30 Key Constraints 30 Participation Constraints 32 Weak Entities 33 Class Hierarchies 35 Aggregation 37 vii viii Database Management Systems Conceptual Database Design With the ER Model 38 Entity versus Attribute 39 Entity versus Relationship 40 Binary versus Ternary Relationships 41 Aggregation versus Ternary Relationships 43 Conceptual Design for Large Enterprises 44 Points to Review 45 3 THE RELATIONAL MODEL 51 Introduction to the Relational Model 52 Creating and Modifying Relations Using SQL-92 55 Integrity Constraints over Relations 56 Key Constraints 57 Foreign Key Constraints 59 General Constraints 61 Enforcing Integrity Constraints 62 Querying Relational Data 64 Logical Database Design ER to Relational 66 Entity Sets to Tables 67 Relationship Sets without Constraints to Tables 67 Translating Relationship Sets with Key Constraints 69 Translating Relationship Sets with Participation Constraints 71 Translating Weak Entity Sets 73 Translating
