Database Systems I Relational Algebra

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数据库data base 核心专业词汇+中英对照+解释

·数据（Data）：反映客观世界的事实，并可以区分其特征的符号：字符、数字、文本、声音、图形、图像、图表、图片等，它们是现实世界中客观存在的，可以输入到计算机中进行存储和管理的。

·信息（Information）：由原始数据经加工提炼而成的、用于决定行为、计划或具有一定语义的数据称为信息。

·数据库DB（Data Base）：是现实世界中相互关联的大量数据及数据间关系的集合。

·数据库管理系统DBMS（Data Base Management System）：是对数据库中的数据进行存储和管理的软件系统。

包括存储、管理、检索和控制数据库中数据的各种语言和工具，是一套系统软件。

·数据库系统DBS（Data Base System）：是对数据库和数据库管理系统的总称。

是指相互关联的数据集合与操纵数据的软件工具集合。

DBS = DB+DBMS·数据库应用程序接口API（Application Programming Interface）：是由DBMS为开发应用程序提供的操纵和访问数据库中数据的接口函数、过程或语言。

·数据库应用程序AP（Application Program）：满足某类用户要求的操纵和访问数据库的程序。

·数据仓库（Data Warehouse）一个数据仓库就是一个自带数据库的商业应用系统。

利用现有的数据资源，把数据转换为信息，从中挖掘出知识，提炼成智慧，创造出效益。

·数据发掘（Data Mining）数据发掘可帮助商业用户处理大量存在的数据，以期发现一些"意外的关系"，以便增加市场份额和利润。

·信息发掘（Information Mining）：信息发掘是指在文档、地图、照片、声音和影像之汪洋大海中发现相关信息，即面向内容的检索。

·数据模式（Data Model）：在数据库中，对数据(实体)的描述称为数据库模式。

计算机外文翻译外文文献英文文献数据库系统

外文资料原文Database Systems1.Introduction to Database SystemToday, more than at any previous time, the success of an organization depends on its ability to acquire accurate and timely data about its operation, to manage this data effectively, and to use it to analyze and guide its activities. Phrases such as the information superhighway have become ubiquitous, and information processing is a rapidly growing multibillion dollar industry .The amount of information available to us is literally exploding, and the value of data as an organizational asset is being widely recognized. This paradox drives the need for increasingly powerful and flexible data management systems .A database is a collection of data , typically describing the activities of one or more related organizations . For example , a university database might contain information about the following .●Entities such as students , faculty , courses , and classrooms .●Relationships between entities , such as students’enrollment in courses , faculty teaching courses , and the use of rooms for courses .A database management system , or DBMS , is software designed to assist in maintaining and utilizing large collections of data , and the need for such systems , as well as their use , is growing rapidly . The alternative to using a DBMS is to use ad hoc approaches that do notcarry over from one application to another , for example , to store the data in files and write application-specific code to manage it .The area of database management systems is a microcosm of computer science in general . The issues addressed and the techniques used span a wide spectrum , including languages , object-orientation and other programming paradigms , compilation , operating systems1concurrent programming , data structures , algorithms ,theory , parallel and distributed systems , user interfaces , expert systems and artificial intelligence , statistical techniques , and dynamic programming .Database management continues to gain importance as more and more data is brought on-line, and made ever more accessible through computer networking. Today the field is being driven by exciting visions such as multimedia databases, interactive video, digital libraries, a host of scientific projects such as the human genome mappin g effort and NASA’s Earth Observation System project, and the desire of companies to consolidate their decision-making processes and mine their data repositories for useful information about their business . Commercially , database management systems represent one of the largest and most vigorous market segments . Thus the study of database systems couldprove to be richly rewarding in more ways than one .2.Database consistsA database consists of a file or a set of files. The information in these files may be broken down into records, each of which consists of one or more fields. Fields are the basic units of data storage, and each field typically contains information pertaining to one aspect or attribute of the entity described by the database. Using keywords and various sorting commands, users can rapidly search, rearrange, group, and select the fields in many records to retrieve or create reports on particular aggregates of data.Database records and files must be organized to allow retrieval of the information. Early systems were arranged sequentially (i.e., alphabetically, numerically, or chronologically); the development of direct-access storage devices made possible random access to data via indexes. Queries are the main way users retrieve database information. Typically, the user provides a string of characters, and the computersearches the database for a corresponding sequence and provides the source materials in which those characters appear. A user can request, for example, all records in which the content of the field for a person’s last name is the word Smith.In flat databases , records are organized according to a simplelist of entities; many simple databases for personal computers are flat in structure. The records in hierarchical databases are organized in a treelike structure, with each level of records branching off into a set of smaller categories. Unlike hierarchical databases, which provide single links between sets of records at different levels, network databases create multiple linkages between sets by placing links, orpointers, to one set of records in another; the speed and versatility of network databases have led to their wide use in business.Relational databases are used where associations among files or records cannot be expressed by links; a simple flat list becomes one table, or “relation”, and multiple relations can be mathematically associated to yield desired information. Object-oriented databases store and manipulate more complex data struct ures, called “objects”, which are organized into hierarchical classes that may inherit properties from classes higher in the chain; this database structure is the mostflexible and adaptable.3.Structure of the Relational databaseThe relational model is the basis for any relational database management system (RDBMS).A relational model has three core components: a collection of objects or relations, operators that act on the objects or relations, and data integrity methods. In other words, it has a place to store the data, a way to create and retrieve the data, and a way to make sure that the data is logically consistent.A relational database uses relations, or two-dimensional tables, to store the information needed to support a business.3.1.Tables, Row, and ColumnsA table in a relational database, alternatively known as a relation, is a two-dimensional structure used to hold related information. A database consists of one or more related tables.Note: Don't confuse a relation with relationships. A relation is essentially a table, and a relationship is a way to correlate, join, or associate two tables.A row in a table is a collection or instance of one thing, such as one employee or one line item on an invoice. A column contains all the information of a single type, and the piece of data at the intersection of a row and a column, a field, is the smallest piece of informationthat can be retrieved with the database's query language. For example, a table with information about employees might have a column calledLAST_NAME that contains all of the employees' last names. Data is retrieved from a table by filtering on both the row and the column.3.2.Primary Keys, Data types, and Foreign KeysRelation: A two-dimensional structure used to hold related information, also known as a table.Row: A group of one or more data elements in a database table that describes a person, place, or thing.Column: The component of a database table that contains all of the data of the same name and type across all rows.Primary Key: A column (or columns) in a table that makes the row in the table distinguishable from every other row in the same table.Data types: numeric values, character or alphabetic values, and date values.A foreign key enforces the concept of referential integrity in a relational database.Foreign Key: A column (or columns) in a table that draws its valuesfrom a primary or unique key column in another table. A foreign key assists in ensuring the data integrity of a table. Referential Integrity A method employed by a relational database system that enforces one-to-many relationships between tables.3.3.Data ModelingIn this process, the developer conceptualizes and documents all the tables for the database. One of the common methods for modeling a database is called ERA, which stands for entities, relationships, and attributes. The database designer uses an application that can maintain entities, their attributes, and their relationships. In general, anentity corresponds to a table in the database, and the attributes of the entity correspond to columns of the table.Data Modeling: A process of defining the entities, attributes, and relationships between the entities in preparation for creating the physical database.The data-modeling process involves defining the entities, defining the relationships between those entities, and then defining theattributes for each of the entities. Once a cycle is complete, it is repeated as many times as necessary to ensure that the designer is capturing what is important enough to go into the database. Let's take a closer look at each step in the data-modeling process.3.4. Defining the EntitiesFirst, the designer identifies all of the entities within the scope of the database application.The entities are the persons, places, or things that are important to the organization and need to be tracked in the database. Entitieswill most likely translate neatly to database tables.。

数据库系统概念(英文精编版.第六版)

Atomicity of updates
Failures
may lead to inconsistencies (1) account_A = account_A – 100 (2) account_B = account_B + 100
Example:

Concurrent access by multiple users
Exercises
Computer users interacts with data in the _______ level A. physical B. logical C. view D. all of the above Application users interact with data in the _______ level. A. physical B. logical C. view D. all of the above How the data are actually stored is called _______ A. Physical level B. Logical level C. View level D. Conceptual level
property is called ( )
A. Data inconsistency C. Data isolation B. Data redundancy D. Data integrity
1.3 View of Data
Hierarchy of Abstraction Levels
Three Abstraction Levels of Data
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本课程学习内容
关系数据模型关系数据库语言

数据库系统工程师招聘笔试题与参考答案2024年

2024年招聘数据库系统工程师笔试题与参考答案(答案在后面)一、单项选择题（本大题有10小题，每小题2分，共20分）1、在数据库系统中，以下哪种数据模型主要用于表达实体与实体之间的关系？A、层次模型B、网状模型C、关系模型D、对象模型2、在SQL语言中，用于删除数据库表中数据的命令是：A、INSERTB、DELETEC、UPDATED、DROP3、在数据库设计中，以下哪个术语用于表示数据库中存储数据的逻辑结构？A. 模式（Schema）B. 视图（View）C. 索引（Index）D. 存储过程（Stored Procedure）4、以下哪种数据库模型适用于需要表示复杂实体间多对多关系的场景？A. 层次模型（Hierarchical Model）B. 网状模型（Network Model）C. 关系模型（Relational Model）D. 文件模型（File Model）5、题干：以下关于数据库管理系统（DBMS）的描述中，正确的是：A、DBMS是数据库的物理存储结构B、DBMS负责数据的安全性和完整性C、DBMS直接管理数据库的物理存储结构D、DBMS是数据库的软件应用系统6、题干：在关系数据库中，以下关于SQL语言的描述中，错误的是：A、SELECT语句用于查询数据库中的数据B、UPDATE语句用于更新数据库中的数据C、DELETE语句用于删除数据库中的数据D、INSERT INTO语句用于向数据库中插入新数据，并指定列名和数据值7、数据库系统工程师在进行数据库设计时，以下哪种范式是最高级别的规范化？A. 第一范式（1NF）B. 第二范式（2NF）C. 第三范式（3NF）D. 第四范式（4NF）8、以下哪个命令用于在SQL中删除一个数据库表中的所有数据，但不删除表本身？A. DROP TABLEB. DELETEC. TRUNCATE TABLED. UPDATE9、题干：在数据库设计中，用于表示实体之间联系的模型是：A. 关系模型B. 网状模型C. 层次模型D. E-R模型 10、题干：以下关于SQL（Structured Query Language）的描述，错误的是：A. SQL是一种用于访问数据库的标准化查询语言。

四川大学数据库系统(双语)Database System教学大纲

College of Software EngineeringUndergraduate Course SyllabusCourse ID 311038040Course Name Database SystemsCourseAttribute■Compulsory □Selective Course Language■English □Chinese Credit Hour 4 Period80Semester□First Fall □First Spring □Second Fall □Second Spring■Third Fall □Third Spring □Fourth Fall □Fourth Spring Instructors Ruan Shuhua, Liang Gang, Lu ZhengtianDescription This course introduces the crucial topics for database systems: Database Planning, Design, Implementation, and Administration. The course concentrates on centralized, relational database systems used for business data processing. The course covers the fundamental concepts and techniques of database systems: Database System Architectural Principles, Data Modeling, Fact-Finding Techniques, Theory and Methodology of Database Design, Query Processing, Storage Strategies, Query Optimization, and Transaction Management. The course then turns to on-going research in database systems, focusing on techniques that have recently been transferred from research to wide-spread commercial implementation. Finally, there is an introduction of new trends in database systems, focusing on applications for supporting decision-making in light of fully distributed and ubiquitously connected world consisting of all range data store and management.Students successfully completing this database fundamentals course will be equipped to handle small to medium size database projects. They will be able to design a database from scratch, design user interface and transaction, write queries against it, and build applications that use the database.Prerequisites 3Programming Fundamentals3Introduction to Object-Oriented Programming 3Discrete Mathematics3Data Structures and Algorithm/Course Design 3Computer Architecture3Operating SystemsTextbook Thomas M. Connolly, et al. Database Systems: A practical approach to Design, Implementation, and Management. 4th Edition ISBN: 0321210255 Addison-Wesley, 2004.Resource 1./~ruanshuhua/index_7.htm2./learning/sql/2008/thankyou/default.mspx3./developerworks/cn/db2/v94./database/index.html5.6.7.8./dist/jakarta/tomcat-59./downloads/packagesGrading 3Assignments and Class Participation: 10% 3Term Project: 20%3Midterm: 20%3Final Exam: 50%Topics 1Background (5 Periods )1.1Introduction to Databases (3 Periods )1.1.1History and Motivation for Information Systems1.1.2Characteristics and Limitations of File-Based Systems *1.1.3Motivation for Database Approach *1.1.4Some Common Database Applications1.1.5Meaning of the Term Database, Database Management Systems (DBMS), andDatabase Systems *1.1.6Typical Functions of a DBMS1.1.7Major Components of the DBMS Environment1.1.8History of the Development of DBMSs1.1.9Advantages and Disadvantages of DBMSs *1.1.10Phone Number Programing on any one Language and on any one DBMS (2Practice Periods) #11.2Database Environment (2 Periods )1.2.1Personnel Involved in the Database Environment *1.2.2The Concepts of Data Abstraction *1.2.3The Three-Level ANSI-SPARC Database Architecture *1.2.4Contents of External, Conceptual, and Internal Levels **1.2.5The Concepts External, Conceptual, and Internal Schemas **1.2.6Purpose of External/Conceptual and Conceptual/Internal Mappings **1.2.7Meaning of Logical and Physical Data Independence *1.2.8Database Languages DDL, DML and Distinction between Them *1.2.9 A Classification of Data Models *1.2.10Purpose/Importance of Conceptual Modeling **1.2.11Meaning of Client–Server Application Architecture and Advantages of This Typeof Architecture for a DBMS2The Relational Model and Languages (20 Periods )2.1The Relational Model (5 Periods )2.1.1Terminology of Relational Model **Topics2.1.2How Tables Are Used to Represent Data2.1.3Connection Between Mathematical Relations and Relations in the RelationalModel2.1.4Properties of Database Relations *2.1.5How to Identify Candidate, Primary, and Foreign Keys **2.1.6Meaning of Null *2.1.7Meaning of Entity Integrity and Referential Integrity **2.1.8Meaning of Enterprise Constraints *2.1.9Purpose and Advantages of Views *2.1.10Setting Integrity Constraints on any one DBMS (2 Practice Periods) #22.2Relational Algebra and Relational Calculus (5 Periods )2.2.1Meaning of the Term Relational Completeness *2.2.2How to Form Queries in Relational Algebra **2.2.3How to Form Queries in Tuple Relational Calculus **2.2.4How to Form Queries in Domain Relational Calculus **2.2.5Categories of Relational DML2.3SQL: Data Manipulation (5 Periods )2.3.1Purpose and Importance of SQL *2.3.2How to Retrieve Data From Database Using SELECT and **2.3.2.1Use Compound WHERE Conditions2.3.2.2Sort Query Results Using ORDER BY2.3.2.3Use Aggregate Functions (COUNT, SUM, AVG, MIN, MAX)2.3.2.4Group Data Using GROUP BY and HAVING2.3.2.5Use Subqueries2.3.2.6Join Tables Together2.3.2.7Perform Set Operations (UNION, INTERSECT, EXCEPT)2.3.3How to Update Database Using INSERT, UPDATE, and DELETE *2.3.4Using SQL Data Manipulation on any one DBMS (2 Practice Periods) #32.4SQL: Data Definition (5 Periods )2.4.1Data Types Supported by SQL Standard *2.4.2Purpose of Integrity Enhancement Feature of SQL **2.4.3How to Define Integrity Constraints Using SQL **2.4.3.1Required Data2.4.3.2Domain Constraints2.4.3.3Entity Integrity Constraints2.4.3.4Referential Integrity Constraints2.4.3.5Enterprise Constraints2.4.4How to Use the Integrity Enhancement Feature in the CREATE and ALTERTABLE Statements *2.4.5How to Create and Delete Views Using SQL *2.4.6How the DBMS Performs Operations on Views *2.4.7Under What Conditions Views Are Updatable **2.4.8Advantages and Disadvantages of Views2.4.9How the ISO Transaction Model Works *2.4.10How to Use the GRANT and REVOKE Statements as a Level of Security *2.4.11Using SQL Data Definition on any one DBMS (2 Practice Periods) #4Topics 3Database Analysis and Design Techniques (20 Periods )3.1Database Planning, Design, and Administration (2 Periods )3.1.1Main Components of an Information System3.1.2Main Stages of Database Application Lifecycle *3.1.3Main Phases of Database Design: Conceptual, Logical, and Physical Design **3.1.4How to Evaluate and Select a DBMS *3.1.5Distinction Between Data Administration and Database Administration *3.1.6Purpose and Tasks Associated with Data Administration and DatabaseAdministration3.2Fact-Finding Techniques (3 Periods )3.2.1Most Commonly Used Fact-Finding Techniques *3.2.2How to Use Each Fact-Finding Technique and the Advantages and Disadvantagesof Each3.2.3Significance of Applying Fact-Finding Techniques to Early Stages of DatabaseApplication Lifecycle *3.2.4How to Use Fact-Finding Techniques in the Database Application Lifecycle3.2.5Types of Facts Collected in Each Stage of Database Application Lifecycle *3.2.6Types of Documentation Produced in Each Stage of Database ApplicationLifecycle *3.2.7Introduction of DreamHome3.2.8Discussing and confirming the Database Project Requirements in the Group (2Practice Periods) #53.3Entity-Relationship Modeling (6 Periods )3.3.1How to Use Entity–Relationship (ER) Modeling in Database Design3.3.2Basic Concepts Associated with ER Model **3.3.3Structural Constraints in ER Model **3.3.4Diagrammatic Technique for Displaying ER Model Using Unified ModelingLanguage (UML) *3.3.5How to Identify and Resolve Problems with ER Models Called Connection Traps3.3.6How to Build an ER Model From a Requirements Specification **3.3.7Building an ER Model by Using Eclipse with UML (2 Practice Periods) #63.4Enhanced Entity-Relationship Modeling (4 Periods )3.4.1Limitations of Basic Concepts of the ER Model and Requirements to RepresentMore Complex Applications Using Additional Data Modeling Concepts3.4.2Most Useful Additional Data Modeling Concepts of Enhanced ER (EER) ModelCalled:3.4.2.1Specialization/Generalization **3.4.2.2Aggregation *3.4.2.3Composition *3.4.3 A Diagrammatic Technique for Displaying Specialization/Generalization,Aggregation, and Composition in an EER Diagram Using UML3.4.4Building an EER Model by Using Eclipse with UML (2 Practice Periods) #73.5Normalization (5 Periods )3.5.1Problems Associated with Redundant Data *3.5.2Identification of Various Types of Update Anomalies Such as Insertion, Deletion,and Modification Anomalies *Topics3.5.3How to Recognize Appropriateness or Quality of the Design of Relations *3.5.4Purpose of Normalization *3.5.5How to Use Functional Dependencies to Group Attributes into Relations being ina Known Normal Form **3.5.6How to Undertake Process of Normalization **3.5.7How to Identify Most Commonly Used Normal Forms, Namely 1NF, 2NF, 3NF,and Boyce–Codd Normal Form (BCNF) *3.5.8How to Identify Fourth (4NF) and Fifth (5NF) Normal Forms3.5.9An Actual Application Example for Normalization (2 Practice Periods) #84Methodology (15 Periods )4.1Conceptual Database Design (7 Periods )4.1.1Purpose of Conceptual Database Design4.1.2How to Decompose the Scope of the Design into Specific Users’ Views of theEnterprise *4.1.3How to Use ER Modeling to Build a Local Conceptual Data Model Based onInformation Given in a View of the Enterprise **4.1.4How to Validate Resultant Conceptual Model to Ensure it is a True and AccurateRepresentation of a View of the Enterprise *4.1.5How to Document Process of Conceptual Database Design *4.1.6End-Users Play an Integral Role Throughout Process of Conceptual DatabaseDesign4.1.7Building ER or EER Model for the Database Project (4 Practice Periods) #94.2Logical Database Design (5 Periods )4.2.1Purpose of Logical Database Design4.2.2How to Remove Features From a Local Conceptual Model that are notCompatible with the Relational Model *4.2.3How to Derive a Set of Relations From a Local Logical Data Model *4.2.4How to Validate These Relations Using the Technique of Normalization *4.2.5How to Validate a Logical Data Model to Ensure It Supports Required UserTransactions *4.2.6How to Merge Local Logical Data Models Based on Specific Views into a GlobalLogical Data Model of the Enterprise **4.2.7How to Ensure that the Resultant Global Model is a True and AccurateRepresentation of Enterprise *4.2.8Building Global Logical Model for the Database Project (2 Practice Periods) #104.3Physical Database Design (3 Periods )4.3.1Purpose of Physical Database Design4.3.2How to Map the Llogical Database Design to a Physical Database Design4.3.3How to Design Base Relations for Target DBMS *4.3.4How to Design Enterprise Constraints for Target DBMS *4.3.5How to Estimate the Size of the Database *4.3.6How to Select Appropriate File Organizations Based on Analysis of Transactions*4.3.7When to Use Secondary Indexes to Improve Performance *4.3.8How to Design Security Mechanisms to Satisfy User Requirements *4.3.9Building the Project Database on the Selected DBMS (2 Practice Periods) #11Topics 5Selected Database Issues (5 Periods )5.1Transaction Management (5 Periods )5.1.1Function and Importance of Transactions5.1.2Properties of Transactions **5.1.3Concurrency Control **5.1.3.1Meaning of Serializability5.1.3.2How Locking Can Ensure Serializability5.1.3.3Deadlock and How It Can Be Resolved5.1.3.4How Timestamping Can Ensure Serializability5.1.3.5Optimistic Concurrency Control5.1.3.6Granularity of Locking5.1.4Recovery Control *5.1.4.1Some Causes of Database Failure5.1.4.2Purpose of Transaction Log File5.1.4.3Purpose of Checkpointing5.1.4.4How to Recover Following Database Failure5.1.5Alternative Models for Long Duration Transactions5.1.6The Database Project Application Design, Such as Transaction Design, UserInterface Design (2 Practice Periods) #126Current Trends (5 Periods )6.1Distributed DBMSs - Concepts and Design (5 Periods )6.1.1What is a Distributed DBMS6.1.2Advantages and Disadvantages of Distributed Databases6.1.3Functions and Architecture for a DDBMS *6.1.4Distributed Database Design *6.1.5Levels of Transparency6.1.6Comparison Criteria for DDBMSs *6.1.7Building the Database System (2 Practice Periods) #137Emerging Trends (10 Periods )7.1Web Technology and DBMSs (5 Periods )7.1.1Basics of Internet, Web, HTTP, HTML, URLs7.1.2Multi-Tier Client-Server Architecture *7.1.3Advantages and Disadvantages of Web as a Database Platform *7.1.4Approaches for Integrating Databases into Web7.1.4.1Scripting Languages7.1.4.2Common Gateway Interface (CGI)7.1.4.3HTTP Cookies7.1.4.4Extending the Web Server7.1.4.5Java and JDBC, SQLJ, Servlets, and JSP7.1.4.6Microsoft Web Solution Platform: ASP and ADO7.1.5Building the Database System (2 Practice Periods) #147.2The Concepts of Data Warehousing and Data marts (5 Periods )7.2.1How Data Warehousing Evolved *7.2.2Main Concepts and Benefits Associated with Data Warehousing7.2.3How Online Transaction Processing (OLTP) Systems Differ From DataWarehousing *Topics7.2.4Problems Associated with Data Warehousing7.2.5Architecture and Main Components of a Data Warehousing *7.2.6Important Information Flows or Processes of a Data Warehouse **7.2.7Main Tools and Technologies Associated with Data Warehousing7.2.8Issues Associated with the Integration of a Data Warehousing and the Importanceof Managing Meta-Data *7.2.9Concept of a Data Mart and the Main Reasons for Implementing a Data Mart *7.2.10Advantages and Disadvantages of a Data Mart7.2.11Main Issues Associated with the Development and Management of Data Marts7.2.12Testing the Database System (2 Practice Periods) #15Notice:3* for emphases3** for emphases and difficulty3#x for the xth Practice Periods (Total 32 Practice Periods)Tools & Environment 3Microsoft Windows Server 200X3J2SDK 1.5 + Tomcat 5.0 + Eclipse 3.3 with UML 3Microsoft SQL SERVER 200XProjects A Web-Based Database SystemStudents will be able to plan, design, create, and maintain a Web-accessible database for a real estate company to keep track of their business, such as the parts, suppliers, and purchase orders, lease renewals, and so on. Included will be the tasks to write Web front-ends for users of the system, such as for the purchasing department to seek quotes, for the suppliers to place bids for work-orders, for the managers to monitor inventory, for client to maintenance personnel, for staff to manage property, and others.Phase 1 (5%)Goal: BackgroundProcedure: Students select a database project, capture necessary facts to build the required database application by using fact-finding techniques, analyse information about the part of organization to be supported by the database application, and use this information to identify users’ requirements for the new database system. Students must learn about the terminology, problems, opportunities, constraints, requirements, and priorities of the organization and the users of the new database system.Deliverables: The collection information and the report of requirements collection and analysis.Due on the fourth week in class. [Late submission policy – you lose 5% (of the maximum points) per day]Phase 2 (5%)Goal: Related Theories and TechniquesProjectsProcedure: Students discuss related theories in the new database system, select a development plaform and evaluate it, select an appropriate DBMS to support the new database application and evaluate it, and after singled out, are familiar with them as soon as possible.Deliverables: The collection information and the report of related theories and techniques.Due on the eighth week in class. [Late submission policy – you lose 5% (of the maximum points) per day]Phase 3 (5%)Goal: The Database System DesignProcedure: Students build data model by using the information in users’ requirements specification, refine conceptual data model, map it to a logical data model, select storage structures and access methods used to achieve efficient access to data on a specific DBMS.At the same time, students define the scope and boundaries of the new database system and the major user views, define the new system and database role (such as Manager or Supervisor), and give the design of user interface and application programs that use and process the database.Deliverables: The report of the database system design.Due on the twelfth week in class. [Late submission policy – you lose 5% (of the maximum points) per day]Phase 4 (5%)Goal: The Database System Implementation and EvaluationProcedure: Students implement the database system design in phase 3, build working model of a database application and evaluate if the database and application programs appear to be working according to requirements, such as to identify features of a system that work well, or are inadequate, to suggest improvements or even new features, to clarify the users’ requirements, to evaluate feasibility of a particular system design.Deliverables: The source code, the implementation state and result of the new database system, and the report of the database system implementation and evaluation.Due on the sixteenth week in class. [Late submission policy – you lose 5% (of the maximum points) per day]Version: 2008-07-15Author: Shuhua Ruan Date: 2008/ 07/ 15Auditor:Mei Hong Date: 2008/07/15Signature of leader：Date： 2008-7-30。

数据库系统概念(database system concepts)英文第六版 PPT 第六章

Database System Concepts - 6th Edition
6.8
©Silberschatz, Korth and Sudarshan
Union Operation
Notation: r s Defined as:
r s = {t | t r or t s}
©Silberschatz, Korth and Sudarshan
Cartesian-Product Operation – Example
Relations r, s:
r x s:
Database System Concepts - 6th Edition
6.12
©Silberschatz, Korth and Sudarshan
Project Operation
Notation:

A , A , , A 1 2 k
(r )
where A1, A2 are attribute names and r is a relation name.
The result is defined as the relation of k columns obtained by erasing
For r s to be valid.
1. r, s must have the same arity (same number of attributes) 2. The attribute domains must be compatible (example: 2nd column of r deals with the same type of values as does the 2nd column of s)

数据库系统概念(database system concepts)英文第六版第一章

l Network model l H i e r a r c h i c a l model
Relational Model
n R e l a t i o n a l model (Chapter 2)
• Columns
n Example of t a b u l a r d a t a i n t h e r e l a t i o n a l model
n Two c l a s s e s of languages l Procedural – u s e r s p e c i f i e s what d a t a i s r e q u i r e d and how t o get those data l Declarative (nonprocedural) – user specifies what data i s r e q u i r e d without s p e c i f y i n g how t o g e t those data
l Difficulty in accessing data 4 Need t o w r i t e a new program t o c a r r y out each new t a s k
l Data i s o l a t i o n — multiple f i l e s and formats l Integrity problems
l Concurrent access by multiple users 4 Concurrent access needed f o r performance 4 Uncontrolled concurrent accesses can lead to inconsistencies – Example: Two people reading a balance (say 100) and updating i t by withdrawing money (say 50 each) a t the same time

计算机的专业英语的名词翻译

第一章（计算机系统概论）digital computer 数字计算机decimal digits 十进制数字binary 二进制bit 位ASCII 美国国家信息交换标准代码computer system 计算机系统hardware system 硬件系统software system 软件系统I/O devices 输入输出设备central processing unit(CPU) 中央处理器memory 存储器application software 应用软件video game 计算机游戏system software 系统软件register 寄存器floating point data浮点数据Boolean布尔值character data字符数据EBCDIC扩充的二十一进制交换代码punched cards穿孔卡片magnetic tape磁带main memory主存vacuum tubes电子管magnetic drum磁鼓transistors晶体管solid-state devices固体器件magnetic cores磁芯integrated circuit（IC）集成电路silicon chip硅芯片multiprogramming多道程序设计timessharing分时分时技术minicomputers小型计算机mainframe大型计算机large-scaleintegrated(LSI)大规模集成very-large-scale integrated(VLSI)超大规模集成word processing文字处理eletronic spreedsheets电子表格database management programs数据库管理程序desktop publishing桌面印刷personalcomputer(PC)个人计算机microcomputer微型计算机storage capacities存储容量stand-alone computer独立计算机local area network(LAN)局域网peripheral devices外部设备assembly line流水线supercomputer巨型计算机第二章（计算机系统结构）memmory subsystem存储子系统I/O subsystem输入输出子系统bus总线system bus系统总线chip 芯片address bus地址总线instructions指令memory location存储单元data bus数据总线control bus控制总线local bus 局部总线microprocessor微处理器register set寄存器组arithmetic logic unit(ALU)运算器clock cycle时钟周期control unit控制器computer architecture计算机体系结构introduction format指令格式addressing modes寻址方式introduction set指令集internal memory内存main memory主存Random Access Memory(RAM)随机存取存储器Read Only Memory (ROM)只读存储器secondary storage副主存储器vitual memory虚拟存储器Dynamic RAM(DRAM)动态存储器refresh circuitry刷新电路Static RAM(SRAM)静态RAMcache memory高速缓冲存储器masked ROM掩膜ROMPROM可编程RAMEPROM可擦写PROMultraviolet light紫外线EEPROM or EEPROM电擦写PROMbasic input/output system(BIOS)基本输入输出系统flash EEPROM 快闪存储器memory hierarchy 存储器体系结构auxiliary memory 辅助存储器storage memory 存储容量keyboard 键盘alphanumeric key字母数字键function key 功能键cursor key 光标键numeric keypad 数字键mouse 鼠标touch screen触屏infrared ray红外线monitor 监视器display screen显示屏laser printer激光打印机ink-jet printer喷墨打印机dot-matrix printer点针式打印机modem调制解调器input-output interface(I/O interface)输入输出接口peripheral外部设备，外设interrupt中断program counter程序计数器vectored interrupt向量中断nonvectored interrupt非向量中断interrupt vector中断向量Direct Memory Acess(DMA)直接存储器存取timeout超时第三单元（计算机体系结构）parallel processing 并行操作serial operations 串行操作instructions stream 指令流data dream 数据流SISD 单指令单数据流SIMD 单指令多数据流MISD 多指令单数据流MIMD 多指令多数据流pipeline processing 流水线处理combinational circuit 组合电路multiplier 乘法器adder 加法器clock pulse 时钟脉冲vector processing 向量处理one-dimensional array 一维数组scalar processer 标量处理器vector instructions 向量指令CISC 复杂指令集计算机decoder 译码器RISC 精简指令集计算机backward compatibility 向下兼容第四单元（算法与数据结构）algorithm 算法parallel algotithm 并行算法primitive 原语syntax 语法semantics 语义pseudocode 伪码exhaustive search 穷举搜索divide-and-conquer algorithm 分治算法dynamic programming 动态规划bottom-up 自上而下top-down 自下而上array 数组one-dimensional array 一维数组pointer 指针program counter 程序计数器instruction pointer 指令指针list 列表linked list 链表singly-linked list 单向链表double-linked list 双向链表circularly-linked list 循环链表FIFO 先进先出LIFO 后进先出stack 栈push 压栈pop 出栈stack pointer 栈指针queue 队列tree 树root 根level 层次degree of a node 结点的度depth of a tree树的深度binary tree 二叉树traversal 遍历M-way search tree M向搜索树第五章（编程语言）Program 程序Program language 程序设计语言Software engineering 软件工程Pseudocode 伪码Flowchart 流程图Coding 编码Program testing 程序测试Desk-checking 手工检查Documentation 文档User documentation 用户文档Operator documentation 操作员文档Programmer documentation 程序员文档Machine language 机器语言Assembly languages 汇编语言High-level languages 高级语言RAD(rapid application development) 快速应用开发Natural language 自然语言Artificial intelligence(AI) 人工智能Compile 编译Assemble 汇编Source code 源代码Object code 目标代码Linker 连接器Executable file 可执行文件Object-oriented programming 面向对象的程序设计Object 对象Class 类ADT（abstract data type）抽象数据类型Member variable 成员变量Class variable 类变量Member function 成员函数Inheritance 继承Derived class 派生类Overload 超载Message 消息Static binding 静态绑定Dynamic binding 动态绑定Polymorphism 多态性Visual programming 可视化编程Markup language 标记语言HTML（hyper text markup language）超文本标记语言Hyperlink 超链接XML(extensible markup language) 可扩展标记语言Java virtual machine java虚拟机第六章（操作系统）Application software 应用软件System software 系统软件Utility software 实用软件Operating system（OS）操作系统Shell 操作系统的外壳程序Graphical user interface（GUI）图形用户界面Kernel 内核Serial processing 串行处理Job 作业Batch processing 批处理Simple batch systems 简单批处理系统Multiprogrammed batch systems 多道程序批处理系统Monitor 监控程序Scheduler 调度程序Multiprogramming 多道程序Multitasking 多任务Time-sharing systems 分时系统Uniprogramming 单道进程Process 进程Process management 进程管理Process control block 进程控制块Mutual exclusion 互斥Multiprocessing 多处理，多进程Distributed processing 分布式管理Concurrent processes 并发处理Deadlock 死锁Synchronize process同步处理Semaphore 信号量Reusable resource 可复用性资源I/O buffers 输入/输出缓冲区I/O channel 输入/输出通道Deadlock prevention 死锁预防Deadlock detection 死锁检测Deadlock avoidance 死锁避免Virtual memory 虚拟内存Logical reference 逻辑引用Real addresse 实地址Paging 分页Segmentation 分段Virtual address 虚拟地址Physical addresses 物理地址Real-time process 实时处理File management 文件管理Plug and play(PnP) 即插即用第七单元(应用软件)application software 应用软件word processing 字处理软件spreadsheet 电子表格personal finance 个人理财presentation graphic 演示图形database manager 数据库管理软件groupware 群件desktop accessory 桌面辅助工具browsers 浏览区desktop publishing 桌面印刷project management 项目管理CAD 计算机辅助设计CAM 计算机辅助制造multimedia authoring 多媒体发布animation 动画MIDI 乐器数字化接口speech synthesis 语音合成insertion point 插入点scroll bar 滚动条window 窗口menu bar 菜单栏pull-down menu 下拉式菜单Button 按钮toolbar 工具条dialog box 对话框default value 缺省值（默认值）macro 宏OLE 对象链接和嵌入clipboard 剪切板column 列row 行cell 单元格cell address 单元格地址cell pointer 单元格指针formula 公式function 函数bar chart 柱形图line chart 线图pie chart 圆饼图workflow software 工作流软件PIM 个人信息管理软件Web browser 浏览器World Wide Web 万维网home page 主页第八单元（数据库）DBMS 数据库管理系统instance 实例schema 模式physical schema 物理模式存储模式内模式logical schema 逻辑模式概念模式模式subschema 子模式外模式data independence 数据独立性physical data independence 物理数据独立性logical data independence 逻辑数据独立性data model 数据模型entity-relationship model 实体联系模型object-oriented model 面向对象模型semantic data model 语义数据类型functional data model 功能数据模型entity 实体entity set 实体集mapping cardinality 映射基数abstract data type 抽象数据类型attribute 属性relation 关系tuple 元组primary key 主键super key 超健candidate key 候选键foreign key 外键DDL 数据定义语言data dictionary 数据字典DML 数据操纵语言procedure DML 过程化DML nonprocedure DML 非过程化DMLSQL 结构化查询语言view 视图the relational algebra 关系代数the tuple relational calculus 元组关系演算atomicity 原子性consistency 一致性duration 持久性transaction 事物DBA 数据库管理员。

数据库系统概论英文教材

数据库系统概论英文教材Data Management Systems: A Comprehensive OverviewData management systems have become an integral part of our digital landscape, enabling organizations to efficiently store, organize, and retrieve vast amounts of information. These systems, commonly known as database management systems (DBMS), have evolved significantly over the years, offering advanced features and capabilities that cater to the ever-growing demands of data-driven enterprises.At the core of a data management system lies the database, which serves as a centralized repository for structured data. Databases can take various forms, such as relational, NoSQL, or object-oriented, each with its own unique characteristics and use cases. Regardless of the specific type, the primary function of a database is to provide a secure, reliable, and scalable means of storing and managing data.One of the key components of a data management system is the database management system software, which acts as an intermediary between the database and the applications or users that interact with it. The DBMS provides a set of tools andfunctionalities that facilitate the creation, maintenance, and manipulation of the database, ensuring the integrity, security, and performance of the data.The DBMS typically includes features such as:1. Data Definition Language (DDL): This component allows users to define the structure of the database, including the creation, modification, and deletion of tables, indexes, and other database objects.2. Data Manipulation Language (DML): The DML enables users to perform operations such as inserting, updating, deleting, and querying data within the database.3. Transaction Management: The DBMS ensures the integrity of data by providing mechanisms for managing transactions, which are a series of operations that must be completed as a single, indivisible unit.4. Concurrency Control: This feature ensures that multiple users or processes can access and modify the same data simultaneously without compromising data integrity.5. Security and Access Control: The DBMS implements securitymeasures to protect the database from unauthorized access, data breaches, and other security threats.6. Backup and Recovery: The DBMS provides tools and procedures for regularly backing up the database and recovering data in the event of system failures or data loss.7. Query Optimization: The DBMS employs various techniques to optimize the execution of complex queries, ensuring efficient data retrieval and performance.Beyond the core DBMS functionalities, modern data management systems often incorporate additional components and technologies to enhance their capabilities. These may include:1. Data Warehousing: Data warehouses are specialized databases designed for analytical and reporting purposes, enabling organizations to consolidate and analyze large volumes of data from various sources.2. Business Intelligence (BI) and Analytics: BI tools and analytical capabilities integrated with the data management system allow organizations to extract insights, identify trends, and make data-driven decisions.3. Big Data Management: With the exponential growth of data, data management systems have evolved to handle large-scale, unstructured data, often leveraging technologies such as Hadoop, NoSQL databases, and stream processing.4. Cloud-based Data Management: The rise of cloud computing has led to the development of cloud-based data management services, offering organizations the flexibility, scalability, and cost-effectiveness of managing their data in the cloud.5. Data Governance and Metadata Management: Effective data management requires comprehensive data governance policies and metadata management, ensuring the quality, security, and compliance of data across the organization.As organizations continue to generate and collect vast amounts of data, the importance of robust data management systems cannot be overstated. These systems play a crucial role in enabling organizations to harness the power of their data, drive informed decision-making, and gain a competitive edge in the digital landscape.In conclusion, data management systems are the backbone of modern data-driven organizations, providing the necessary tools and infrastructure to store, manage, and leverage data effectively. Byunderstanding the core components and capabilities of these systems, organizations can optimize their data management strategies and unlock the full potential of their data assets.。

数据库原理英文课件chapter4- Relational Algebra.ppt

6
Operators
运算符
集合
运算符
专门的
关系
运算符
含义
并差交广义笛卡尔积
选择投影连接
除
运算符
比较
>
运算符
>=
<
<=
=
逻辑
运算符
含义
大于大于等于
小于小于等于
等于不等于
非与或
7
Set Operators
R U S: union, the set of elements that are in R or S or both. RS: intersection, the set of elements that are in both R and S. R - S: difference, the set of elements that are in R but no in S. Required
Called natural join.
3
What is Relational Algebra?
An algebra whose operands are relations or variables that represent relations. Operators are designed to do the most common things that we need to do with relations in a database.
Example title, year, length (Movie)
10
Selection
C (R)
C is a condition (as in “if” statements) that refers to attributes of R. The result is a new relation with a subset of R’s tuples that satisfy C.

数据库英文版第六版课后答案

数据库英文版第六版课后答案Chapter 1: IntroductionQuestions1.What is a database?A database is a collection of organized and structured data stored electronically in a computer system. It allows users to efficiently store, retrieve, and manipulate large amounts of data.2.What are the advantages of using a database system?–Data sharing and integration: A database system allows multiple users to access and share data simultaneously.–Data consistency and integrity: A database system enforces rules and constraints to maintain the accuracy and integrity of the data.–Data security: A database system provides access control mechanisms to ensure that data is accessed by authorized users only.–Data independence: A database system separates the data from the application programs that use it, allowing for easier applicationdevelopment and maintenance.Exercises1.Discuss the advantages and disadvantages of using a database system.Advantages:–Data sharing and integration–Data consistency and integrity–Data security–Data independenceDisadvantages:–Cost: Database systems can be expensive to set up and maintain.–Complexity: Database systems require a certain level of expertise to design, implement, and manage.–Performance overhead: Database systems may introduce some overhead in terms of storage and processing.Overall, the advantages of using a database system outweigh the disadvantages in most cases, especially for large-scale applications with multiple users and complex data requirements.Chapter 2: Relational Model and Relational Algebra Questions1.What is a relation? How is it represented in the relational model?A relation is a table-like structure that represents a set of related data. It is represented as a two-dimensional table with rows and columns, where each row corresponds to a record and each column corresponds to a attribute or field.2.What is the primary key of a relation?The primary key of a relation is a unique identifier for each record in the relation. It is used to ensure the uniqueness and integrity of the data.Exercises1.Consider the following relation:Employees (EmpID, Name, Age, Salary)–EmpID is the primary key of the Employees relation.–Name, Age, and Salary are attributes of the Employees relation.2.Write a relational algebra expression to retrieve the names of all employees whose age is greater than 30.π Name (σ Age > 30 (Employees))Chapter 3: SQLQuestions1.What is SQL?SQL (Structured Query Language) is a programming language designed for managing and manipulating relational databases. It provides a set of commands and statements that allow users to create, modify, and query databases.2.What are the main components of an SQL statement?An SQL statement consists of the following main components:–Keywords: SQL commands and instructions.–Clauses: Criteria and conditions that specify what data to retrieve or modify.–Expressions: Values, variables, or calculations used in SQL statements.–Operators: Symbols used to perform operations on data. Exercises1.Write an SQL statement to create a table called。

数据库原理与应用英语

数据库原理与应用英语Database Principles and ApplicationsIntroduction:Database Principles:1. Data Organization: A database is a structured collection of data that is organized and stored in a systematic manner. The organization of data is achieved through the use of tables, which consist of rows and columns. Each row in a table represents a record, while each column represents a specific attribute or characteristic of that record.2. Data Independence: One of the key principles of database systems is data independence. This means that the physical organization of data is separate from the logical structure, allowing for easier management and modification of data. Changes to the physical structure, such as storage media or access methods, do not affect the logical structure or the way data is represented to users.3. Data Integrity: Data integrity refers to the accuracy and consistency of data. It is crucial to ensure that databases contain valid and reliable information. Various mechanisms, such as constraints, triggers, and referential integrity, are used to enforce data integrity by preventing the entry of incorrect or inconsistent data.4. Data Security: Data security is another important principle of database systems. It involves protecting sensitive and confidential information from unauthorized access, use, disclosure, or modification. Security measures, such as encryption, access control, and audit trails, are implemented to safeguard the data stored in databases.Database Applications:1. Business Management: Databases play a vital role in managing business operations. They are used to store and handle various types of business data, such as customer information, inventory details, sales records, and financial data. By efficiently storing and retrieving data, businesses can make informed decisions, improve efficiency, and streamline their operations.4. Healthcare: Databases are critical for managing patient records, medical histories, and other healthcare-related information. Electronic Health Record (EHR) systems storepatient data and facilitate its secure sharing among healthcare providers. Databases also support medical research, drug discovery, and clinical trials by providing a structured repository of medical information.Conclusion:。

《数据库英文翻译》word版

databaseDatabase is in accordance with the data structure to organize, storage and management of data warehouse, which arises from fifty years ago, with the dating of information technology and the development of the market, especially since the 1990s, data management is no longer merely data storage and management, and transformed into user needs of the various data management way. The database has a variety of types, from the most simple storage have various data form to can be carried out mass data storage of large database systems are obtained in each aspect has extensive application.The birth of data managementDatabase's history can be traced back to fifty years ago, when the data management is very simple. Through a lot of classification, comparison and form rendering machine running millions of punched CARDS for data processing, its operation results on paper printed or punched card made new. While the data management is punched card for all these physical storage and handling. However, 1 9 5 1 year Remington Rand corporation (Remington Rand Inc.) an enzyme called Univac I computer launched a a second can input hundreds of recording tape drives, which has caused data management revolution. 1956 IBM produce the first disk drives -- the RAMAC Model 305. This drives have 50 blanks, each blanks diameter is 2 feet, can store 5 MB of data. The biggest advantage is use disk can be randomly access data, and punched CARDS and tape can order access data.Database system appears in the 1960s the bud. When computer began to widely used in data management, the sharing of data put forward more and more high demand. The traditional file system already cannot satisfy people's needs. Manage and share data can unify the database management system (DBMS) came into being. The data model is the core and foundation of database system, various DBMS software are based on a data model. So usually in accordance with the characteristics of the data model and the traditional database system into mesh database, the hierarchy database and relational database three types.Structured query language (SQL)commercial database systems require a query language that is more user friendly. In this chapter,we study SQL, themost inﬂuential commercially marketed query language, SQL. SQL uses a combination ofrelational-algebra and relational-calculus constructs.Although we refer to the SQL language as a “query language,” it can do much more than just query a database. It can deﬁne the structure of the data, modify data in the database, and specify security constraints.It is not our intention to provide a complete users’ guide for SQL.Rather,we present SQL’s fundamental constructs and concepts. Individual implementations of SQL may differ in details, or may support only a subset of the full language.2.1 BackgroundIBM developed the original version of SQL at its San Jose Research Laboratory (nowthe Almaden Research Center). IBM implemented the language, originally called Sequel, as part of the System R project in the early 1970s. The Sequel language hasevolved since then, and its name has changed to SQL (Structured Query Language). Many products now support the SQL language. SQL has clearly established itself as the standard relational-database language.In 1986, the American National Standards Institute (ANSI) and the International Organization for Standardization (ISO) published an SQL standard, called SQL-86.IBM published its own corporate SQL standard, the Systems Application Architecture Database Interface (SAA-SQL) in 1987. ANSI published an extended standard forSQL, SQL-89, in 1989. The next version of the standard was SQL-92 standard, and the most recent version is SQL:1999. The bibliographic notes provide references to these standards.Chapter 4 SQLIn this chapter, we present a survey of SQL, based mainly on the widely implemented SQL-92 standard. The SQL:1999 standard is a superset of the SQL-92 standard;we cover some features of SQL:1999 in this chapter, and provide more detailed coverage in Chapter 9. Many database systems support some of the new constructs inSQL:1999, although currently no database system supports all the new constructs. You should also be aware that some database systems do not even support all the features of SQL-92, and that many databases provide nonstandard features that we donot cover here.The SQL language has several parts:•Data-deﬁnition language (DDL). The SQL DDL provides commands for deﬁning relation schemas, deleting relations, and modifying relation schemas.•Interactive data-manipulation language (DML). The SQL DML includes a query language based on both the relational algebra and the tuple relational calculus. It includes also commands to insert tuples into, delete tuples from,and modify tuples in the database.•View deﬁnition.The SQL DDL includes commands for deﬁning views.•Transaction control. SQL includes commands for specifying the beginning and ending of transactions.•Embedded SQL and dynamic SQL. Embedded and dynamic SQL deﬁne how SQL statements can be embedded within general-purpose programming languages, such as C, C++, Java, PL/I, Cobol, Pascal, and Fortran.•Integrity.The SQL DDL includes commands for specifying integrity constraints that the data stored in the database must satisfy. Updates that violate integrity constraints are disallowed.•Authorization.The SQL DDL includes commands for specifying access rights to relations and views.In this chapter, we cover the DML and the basic DDL features of SQL.Wealso brieﬂy outline embedded and dynamic SQL, including the ODBC and JDBC standards for interacting with a database from programs written in the C and Java languages.SQL features supporting integrity and authorization are described in Chapter 6,while Chapter 9 outlines object-oriented extensions to SQL.The enterprise that we use in the examples in this chapter, and later chapters, is abanking enterprise with the following relation schemas:Branch-schema = (branch-name, branch-city, assets)Customer-schema = (customer-name, customer-street, customer-city)Loan-schema = (loan-number, branch-name, amount)Borrower-schema = (customer-name, loan-number)Account-schema = (account-number, branch-name, balance)Depositor-schema = (customer-name, account-number)Note that in this chapter, as elsewhere in the text, we use hyphenated names for schema, relations, and attributes for ease of reading. In actual SQL systems, however,hyphens are not valid parts of a name (they are treated as the minus operator). A simple way of translating the names we use to valid SQL names is to replace all hy phens by the underscore symbol (“ ”). For example, we use branch name in place ofbranch-name.2.2 Basic StructureA relational database consists of a collection of relations, each of which is assigneda unique name. Each relation has a structure similar to that presented in Chapter3.SQL allows the use of null values to indicate that the value either is unknown or does not exist. It allows a user to specify which attributes cannot be assigned null values,as we shall discuss in Section4.11.The basic structure of an SQL expression consists of three clauses: select, from,and where.•The select clause corresponds to the projection operation of the relational algebra. It is used to list the attributes desired in the result of a query.•The from clause corresponds to the Cartesian-product operation of the relational algebra. It lists the relations to be scanned in the evaluation of the expression. •The where clause corresponds to the selection predicate of the relational algebra. It consists of a predicate involving attributes of the relations that appear in the fromclause.That the term select has different meaning in SQL than in the relational algebra is an unfortunate historical fact. We emphasize the different interpretations here to minimize potential confusion.A typical SQL query has the formselect A1,A2,...,Anfrom r1,r2,...,rmwhere PEach Ai represents an attribute, and each ri arelation. P is a predicate. The query isequivalent to the relational-algebra expressionΠA1,A2,...,An(σP (r1 × r2 × ··· × rm))If the where clause is omitted, the predicate P is true. However, unlike the result of a relational-algebra expression, the result of the SQL query may containmultiple copies of some tuples; we shall return to this issue in Section 4.2.8.SQL forms the Cartesian product of the relations named in the from clause,performs a relational-algebra selection using the where clause predicate, and then projects the result onto the attributes of the select clause. In practice, SQL may convert the expression into an equivalent form that can be processed more efﬁciently.However, we shall defer concerns about efﬁciency to Chapters 13 and 14.In 1974, IBM's Ray Boyce and Don Chamberlin will Codd relational database 12 rule mathematical definition with simple keyword grammar expression comes out, put forward the landmark Structured Query Language (SQL) Language. SQL language features include inquiry, manipulation, definition and control, is a comprehensive, general relational database language, and at the same time, a highly the process of language, only request users do not need pointed out how do pointed out. SQL integration achieved database of all life cycle operation. SQL database provides and relations interact with the method, it can work with standard programming language. The date of the produce, SQL language became the touchstone of inspection relational database, and SQL standard every variation of guidingthe relational database product development direction. However, until the twentieth century, the mid 1970s to the theory of relation in commercial database Oracle and SQL used in DB2.In 1986, the SQL as ANSI relational database language American standards, that same year announced the standard SQL text. Currently SQL standard has three versions. ANSIX3135 - is defined as the basic SQL Database Language - 89, "Enhancement" SQL. A ANS89] [, generally called SQL - 89. SQL - 89 defines the schema definition, data operation and the transaction. SQL - 89 and subsequent ANSIX3168-1989, "Language - Embedded SQL Database, constituted the first generation of SQL standard. ANSIX3135-1992 [ANS92] describes a enhancements of SQL, now called SQL - 92 standards. SQL - 92 including mode operation, dynamic creation and SQL statements dynamic executive, network environment support enhancement. Upon completion of SQL - 92 ANSI and ISO standard, they started SQL3 standards development cooperation. The main features SQL3 abstract data types support, for the new generation of object relational database provides standard.The nature of database data1. Data integrity: database is a unit or an application field of general data processing system, he storage is to belong to enterprise and business departments, organizations and individuals set of related data. Database data from a global view, he according to certain data model organization, description and storage. Based on the structure of data between natural relation, thus can provide all the necessary access route, and data no longer deal with a certain applications, but for total organization, with a whole structural features.2. Data sharing: database data is for many users sharing their information and the establishment, got rid of the specific procedures restrictions and restraint. Different users can use the database according to their respective usage the data; Multiple users can also Shared database data resource, i.e., different users can also access database in the same data. Data sharing each user not only meets the requirements of information, but also meet the various users of information communication between the requirements.Object-oriented databaseAlong with the development of information technology and the market, people found relational database system, while technology is mature, but its limitations is obvious: it can be a very good treatment of so-called "form of data", but of dominating the more and more complex appear helpless type of data. Since the 1990s, technology has been studying and seek new database system. But in what is the development direction of the new database system, industry once is quite confused. The influence of agitation by technology at the time, for quite some time, people put a lot of energy spent on research "object-oriented database system (object oriented database)" or simply as "OO database system". What is worth mentioning, the United States Stonebraker professor proposed object-oriented RDS theory once favored by industry. And in Stonebraker himself Informix spend big money was then appointed technology director always.However, several years of development, spatio-temporal object-oriented relational database system product market development situation is not good. Theoretically perfect sex didn't bring market warm response. The main reason of success, the main design thought database products with new database system is an attempt to replace the existing database system. This for many has been using database system for years and accumulated the massive job data, especially big customer for customers, is unable to withstand the conversion between old and new data that huge workload and big spending. In addition, object-oriented RDS system makes query language extremely complex, so whether database development businessman or application customers depending on the complicated application technology to be a dangerous road.Basic structureThe basic structure of database, reflects the three levels of observation database of three different Angle.(1) physical data layer.It is the most lining, is database on physical storage equipment actually stored data collection. These data are raw data, the object, the user isprocessed by internal model describing the throne of handled the instructions of string, character and word.(2) conceptual data layer.It is a layer of database, is among the whole logic said. Database Points out the logic of each data definition and the logical connection between data collection of storage and record, is. It is related to the database all objects logical relationship, not their physical condition, is under the database administrator concept of database.(3) logical data layer.It is the user sees and use the database, says one or some specific users use collections of data, namely the logical record set.Database different levels is the connection between conversion by mapping.Main features(1) to implement the data sharing.Data sharing contains all users can also access database data, including the user can use all sorts of ways to use the database through interfaces, and provide data sharing.(2) reduce data redundancy.Compared with the file system, because the database to achieve data sharing so as to avoid the user respective establish application documentation. Reduce a lot of repeating data, reduce the data redundancy, maintain the consistency of the data.(3) data of independence.Data independence including database database of logical structure and application independent, also including data physical structure change does not affect the data of the logical structure.(4) data realize central control.File management mode, data in a decentralized state, different user or same users in different treatment had no relation between the documents.Using the database of data can be concentrated control and management, and through the data model of data organization and said the relation between data.(5) the data consistency and maintainability, to ensure the safety and reliability of the data.Mainly includes: (1) the safety control: to prevent data loss, error updating and excessive use; (2) the integrity control: ensure data accuracy, effectiveness and compatibility; (3) the concurrent control: make in the same time period to allow data realization muli-access, and can prevent users of abnormal interaction between; (4) fault finding and recovery: the database management system provides a set of method, can isolate faults and repair fault, thereby preventing data breaches(6) fault recovery.The database management system provides a set of method, can isolate faults and repair fault, thereby preventing data breaches. Database system can restore database system is running as soon as possible, is probably the fault occurred in the physical or logical error. For instance, in system caused by incorrect operation data error, etc.Database classification1. The MaiJie openPlant real-time databaseReal-time database system is a new field in database theory expansion, in power, chemical, steel, metallurgy, papermaking, traffic control and securities finance and other fields has a very broad application prospect. It can provide enterprises with high speed, timely real-time data services, to the rapidly changing real-time data to carry on the long-term effective history storage, is a factory control layer (fieldbus, DCS, PLC, etc) and production management system of the connection between the bridge, also process simulation, advanced control, online optimization, fault diagnosis system data platform.OpenPlant real-time database system used in today's advanced technology and architecture, can realize safe, stable and field each control system of the interface, and collected data efficient data compression and China's longhistory of storage, meanwhile, we also provide convenient client application and general data interface (API/DDE/ODBC/JDBC/OPC, etc.), make the enterprise management and decision makers can prompt, and comprehensive understanding of the current production situation, also can look back at past production conditions, the timely discovery and the problems existing in the production, improve equipment utilization rate, reduce production cost, the enhancement enterprise's core competitive ability.2. IBM DB2As the pioneer and relational database fields, IBM pilot in 1977 completed System R System prototype, 1980 began to provide integrated database server - System / 38, followed by SQL/DSforVSE and VM, and its initial version is closely related with SystemR research prototype. In 1983 forMVSV1 DB2 launch. This version of the objective is to provide the new plan promised simplicity, data don't correlation and user productivity. 1988 DB2 for MVS provides a powerful online transaction processing (OLTP) support, 1989 and 1993 respectively to remote work unit and distributed work unit realized distributed database support. Recently launched Universal Database 6.1 is DB2 Database model gm, is the first online function with multimedia relational Database management system, support includes a series of platform, Linux.3. OracleOracle predecessor called SDL Ellison and another by a benchwarmer in 1977 founded two programmers, they have developed their own fist product in the market, a large sale, 1979, Oracle company introduces the first commercial SQL relational database management system. Oracle corporation is the earliest development relational database, its product support and producers of the most widely operating system platform. Now Oracle relational database products market share a front-runner.4. InformixInformix founded in 1980, the purpose is for Unix operating system to provide professional such open relational database products. The company's name from Information and Informix is the combination of Unix. Informix first truly support SQL database products is the relationship between Informix SE(StandardEngine). InformixSE is at the time of the microcomputer Unix environment main database products. It is also the first to be transplanted into the commercial database products on Linux.5. SybaseSybase company was founded in 1984, the company name "Sybase" from "the system" and "database" combination of meaning. One of the company's founder Bob Sybase Epstein is Ingres university edition (and System/R the same period the relational database model products) of main design personnel. The company's first a relational database products are launched in 1987 SQLServer1.0 Sybase may. Sybase are first proposed the structure of database system/Server thoughts, and took the lead in SQLServer Sybase realize.6. SQL ServerIn 1987, Microsoft and IBM cooperative development complete OS / 2, IBM in its sales OS / 2 ExtendedEdition system binding Manager, and 2Database OS/production line is still lack of database of Microsoft products. Therefore, Microsoft will Sybase, Sybase foreign-exchange signed cooperation agreements with the technical development, the use of Sybase based on OS / 2 platform relational database. In 1989, Microsoft released SQL Server version 1.0.7. PostgreSQLPostgreSQL is a characteristic very complete free software objects - relational database management system (ORDBMS), and many of its characteristic is many of today's commercial database predecessor. The earliest PostgreSQL Ingres project started in BSD the. The characteristics of PostgreSQL covering the SQL - 2 / SQL - 92 and SQL - 3. First, it includes can say to the world's most abundant data types of support; Second, at present PostgreSQL is the only support affairs, son query, multiple versions parallel control system, data integrity checking the only features such as a free software database management system.8. MySQLMySQL is a small relational database management system, developers for Sweden mySQL AB corporation. In January 2008, was 16 from takeover. Currently MySQL is widely used in the small and medium-sized websites on the Internet. Because of its small size, speed, overall has low cost, especially open-source this one characteristic, many small and medium-sized web site, in order to reduce the overall cost of ownership website and selected MySQL as website database9 in Access databasesAmerican Microsoft company in 1994 launched microcomputer database management system. It has friendly interface, easy easy to use, development is simple, flexible, and other features, is the interface typical of the new generation of desktop database management system. Its main features below:(1) perfect management, various database objects of strong data organization, user management, safety inspection functions.(2) strong data processing functions, in a group level of network environment, use Access development multi-user database management system have traditional XBASE (DBASE, FoxBASE collectively) database system can achieve client/Server (Cient/Server) structure and the corresponding database security mechanism, the Access has many advanced large database management system has the characteristics, such as transaction processing/error rollback ability, etc.(3) can be easily generate various data object, using the data stored build forms and statements, visibility.(4) as Office suite, and part of the integrated, realize seamless connection version.(5) can use Web searching and release data, realization and Internet connection. Access mainly suitable for small and medium application system, or as a client/server system of the client database.10. SQLiteThe ACID is to comply with SQLite relational databases management system, it contained within a relatively small C library. It is ichardHipp D.Restablished public domain project. Not as common client/server architecture examples, with SQLite engine is not a process of communication independent process, but connected to the program become a major part of it. So the main communication protocol is within the programming language direct API calls. This in gross consumption, time delay and overall simplicity have positive role. The entire database (definition, table, indexing and data itself) are both in the host host stored in a single file. It is through the simple design of starting a business in the whole data files and complete lock.11. FoxPro databaseAt first by American Fox 1988, 1992 Fox launched by Microsoft company, have introduced after the takeover FoxPro2.5, 2.6 and VisualFoxPro etc, its function and performance version has greatly improved. FoxPro2.5, 2.6 into DOS and Windows two versions, respectively in DOS and running Windows environment. FoxPro FoxBASE in function and performance than and have improved greatly, mainly introducing the window, button, list box and text box control such as to enhance the system development capabilities.Common databases1. MySQL is the most popular open source SQL database management system, the company develops by MySQL AB, issuing, and support. MySQL AB is founded by several MySQL developer a commercial company. It is a second-generation open-source company, combined with open source value orientation, method and successful business model.Features:MySql core program using fully multi-threaded programming. Threading is lightweight processes, it can be flexibly provides services for users, and the system resources. But manyMySql can run in different operating systems. Say simply, MySql can support Windows95/98 / NT / 2000 and UNIX, Linux and OS from various operating system platform.MySql have a very flexible and safe access and password system. When a customer and MySql server connection between all the password, theytransmit encrypted, and MySql support host authentication.Support ODBC for Windows. MySql support all the ODBC 2.5 function and many other functions, like this may use Access connections MySql server, thus make the MySql applications are greatly extend.MySql support large database. Although written in Php web page for it as long as can deposit hundreds of above record data is enough, but MySql can easily support millions of recorded database.MySql have a very rapid and stable memory allocation system based on the thread, can continue to use face don't have to worry about its stability.The strong search function. MySql support inquires the ramp of the SELECT and statements all operators and function, and can be in the same query from different database table mixes, thus make inquires the become quicker and easier.PHP provides strong support for MySql, provide a whole set of the PHP function to MySql MySql, carry on the omni-directional support.2. Based on the server is SQLServer database can be used for medium and large capacity data applications, on the function management is much more ambitious than Access. In handling mass data efficiency, backstage development aspects of flexibility, scalability is strong. Because now database are using standard SQL language to database management, so if it is standard SQL language, both basically can generic. 92HeZu nets all rent space can be used both double Access database, while supporting the SQL Server. SQL Server and more extended stored procedure, can use the database size without limit restrictions.Graphical user interface, make the system management and database management more intuitive and simple.The real client/server architecture.Rich programming interface tools for users to program designed to provide more choices.SQL Server with Windows NT, using a fully integrated many functions, suchas NT send and receive messages, management login security, etc. SQL Server can be a very good and Microsoft BackOffice product integration.Has the very good flexibility, can span from running Windows 95/98 laptop to run Windows 2000 large multiprocessor and so on many kinds of platform use.Technical support to the Web, users can easily will database data released on to the Web page.SQL Server provides the data warehouse function, this function only in Oracle and other more expensive DBMS is only found in.3. Access is a desktop database, is suitable only for data quantity is little, in dealing with the application of a database of data and single visit is very good, the efficiency is high. But it's also visit the client can't more than four. The access database has certain limit, if the data reach 100M or so, is very easy to create the server iis feign death, or consume server memory to crash the server.The future development trendWith the expansion of information management content, appeared to rich variety of data model (hierarchical model, meshy model, relation model, object-oriented model, half structural model and so on), the new technology also emerge in endlessly (data streams, Web data management, data mining, etc.). Now every few years, international senior database experts assembled, discusses database research status, problems and future needs the new technology focus attention. The past existing several similar reports include: 1989 The Future Directions inDBMS Laguna BeachParticipants true - DatabaseSystems: Achievements in 1990, Opportunities, 1995. Inmon W.H. Database 1991: constructing The publication of The data warehouse"。

Lecture06

Capture part of world as an E/R model Convert E/R models to relational models Convert relational models to good (normal) forms
Next:
Create, update, query tables with R.A/SQL Write SQL/DB-connected applications
Operations Operands: Variables, Constants, expressions
Expressions:
Vars & constants Operators applied to expressions They evaluate to values
Algebra High-school Relational
3
Guifeng Zheng, DBMS, SS/SYSU
3-minute Normalization Review
1. 2. 3.
Q: What’s required for BCNF? Q: How do we fix a non-BCNF relation? Q: If As Bs violates BCNF, what do we do? Q: Can BCNF decomposition ever be lossy? Q: How do we combine two relations? Q: Can BCNF decomp. lose FDs? Q: Why would you ever use 3NF?
Database Systems Lecture #6
Guifeng Zheng School of Software, SYSU Fall, 2010

Database Systems I Relational Algebra

61
Relational Algebra Operations
Renaming of relations / attributes. Additional operations:
Intersection, join, division. Not essential, can be implemented using the five basic operations. But (very!) useful.
query input relations.
31 lubber 8 44 guppy 5
55.5 35.0
58 rusty 10 35.0
CMPT 354, Simon Fraser University, Fall 2008, Martin Ester
60
Relational Algebra Operations
Relational model supports simple, powerful query languages:
Strong formal foundation based on logic. High level, abstract formulation of queries. Easy to program. Allows the DBS to do much optimization.
S(R)
CMPT 354, Simon Fraser University, Fall 2008, Martin Ester
63
Projection
One input relation.
57
Relational Algebra
In relational algebra, operands are relations / tables, and an expression evaluates to a relation / set of tuples.

Database Systems (资料库系统)

11
Any Question(s) on Administrative Things?
12
Introduce an interesting project in Ubiquitous Computing
(Won’t be Tested)
13
Topobo (MIT media lab)
• Redefine programming
5
General Comments on Textbook
• Widely used among U.S. Universities 3~4 years ago. • Bad
– Ambiguous writing, inconsistent wording – “More liபைடு நூலகம்e an experience report from researchers rather than introductory textbooks for beginners”
17
What can DBMS do for applications?
• Store huge amount of data (e.g., TB+) over a long period of time • Allow apps to query and update data
– Query: what is Mary’s grade in the “Operating System” course? – Update: enroll Mary in the “Database” course
18
More on what can DBMS do for applications?
• Protect from incorrect inputs • Support concurrent access from multiple users

Database Systems I Relational Algebra

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Lecture06

Database Systems I Relational Algebra

Database Systems (资料库系统)

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数据库原理英文课件chapter4- Relational Algebra.ppt