TAILIEUCHUNG - UNIT 5. DATABASE MANAGEMENT SYSTEMS LESSON 5. RELATIONAL DATABASES AND SQL BASICSNOTE

It is normally a noun. An Entity would have one or many attributes. It may be physical object (. person) event (. appointment) concept (. order). descriptor (describe properties of the entity, . lastname of the person) ATTRIBUTE A property of an entity identifier (uniquely distinguish entity instances - primary key in relational context) composite (a group of attributes used as a single attribute) Describes the relationship between entities. Typically expressed in verbs (. has). There are no well defined standards of the EER notation | Information Management Resource Kit Module on Management of Electronic Documents UNIT 5. DATABASE MANAGEMENT SYSTEMS LESSON 5. RELATIONAL DATABASES AND SQL BASICS NOTE Please note that this PDF version does not have the interactive features offered through the IMARK courseware such as exercises with feedback pop-ups animations etc. We recommend that you take the lesson using the interactive courseware environment and use the PDF version for printing the lesson and to use as a reference after you have completed the course. FAO 2003 5. Database management systems - 5. Relational databases and SQL basics - page 1 Objectives At the end of this lesson you will be able to understand the principles on which relational databases and SQL are based. apply the Extended Entity Relationship EER model to a simple set of data. understand the function of the main SQL statements. Documents which allow you to create and modify relational databases using SQL are available for download and print at the end of the lesson. Introduction The most popular kind of database is the relational database invented in the 70s where the data is stored as relations. The first step in building a relational database is deciding how to organize data that is designing the database. Then the database can be created and manipulated using the Structured Query Language SQL which allows interaction with relational databases. 5. Database management systems - 5. Relational databases and SQL basics - page 2 Principles I Relations can be viewed as two-dimensional tables where all the data is stored. Let s consider for example this Person table. Table PERSON Attribute ID FirstName Lastname Work Phone Home Phone Tuple 1001 Laura Williams 10 02 Paul Smith 10 03 David Fisher Primary Key A row or tuple in a table is identified by a primary key. The other information in the row is referred to as attributes. Specifically the ID column in this table

• Cơ sở dữ liệu
• digital information
• information technologies
• digital revolution
• production information
• distribution information
• university’s website
• Information storage and management
• Storage system
• Information storage
• Information management
• Protecting digital information
• Storage networking technologies
• Management information systems
• Managing the digital firm
• Information systems
• Global business today
• Information technology infrastructure
• Information systems today
• Managing in the digital world
• Enhancing business intelligence using big data
• Securing information systems
• Acquiring information systems
• Enterprise information systems
• Managing knowledge
• Enhancing decision making
• Building information systems
• The digital world
• Gaining competitive advantage
• The information systems infrastructure
• Enhancing collaboration using web 2
• Enhancing business intelligence
• Digital Signature Information Security
• Authentication information Security
• Digital Signature theme
• Hash Function Research
• Digital Signature Schema
• Digital television technology
• Digital television
• Frequency analysis
• Digital television channel coding
• DVB service information
• System information protocol
• Lecture Management Information Systems
• Bài giảng Hệ thống thông tin quản lý
• E commerce business
• Digital Markets
• Digital Goods
• E commerce marketing