McGraw-Hill/Irwin © 2008 The McGraw-Hill Companies, All Rights Reserved Chapter 7 Storing Organizational Information - Databases

7-2 Learning Outcomes 7.1 Define the fundamental concepts of the relational database model 7.2 Evaluate the advantages of the relational database model 7.3 Compare relational integrity constraints and business-critical integrity constraints

7-3 Learning Outcomes 7.4Describe the role and purpose of a database management system 7.5 List and describe the four components of a database management system 7.6 Describe the two primary methods for integrating information across multiple databases

7-4 Relational Database Fundamentals Information is everywhere in an organization Information is stored in databases –Database – maintains information about various types of objects (inventory), events (transactions), people (employees), and places (warehouses)

7-5 Relational Database Fundamentals Database models include: –Hierarchical database model – information is organized into a tree-like structure (using parent/child relationships) in such a way that it cannot have too many relationships –Network database model – a flexible way of representing objects and their relationships –Relational database model – stores information in the form of logically related two-dimensional tables

7-6 Entities, Entity Classes, and Attributes Entity – a person, place, thing, transaction, or event about which information is stored –The rows in each table contain the entities –In Figure 7.1 CUSTOMER includes Dave’s Sub Shop and Pizza Palace entities Entity class (table) – a collection of similar entities –In Figure 7.1 CUSTOMER, ORDER, ORDER LINE, DISTRIBUTOR, and PRODUCT entity classes

7-7 Entities, Entity Classes, and Attributes Attributes (fields, columns) – characteristics or properties of an entity class –The columns in each table contain the attributes –In Figure 7.1 attributes for CUSTOMER include: Customer ID Customer Name Contact Name Phone

7-8 Keys and Relationships Primary keys and foreign keys identify the various entity classes (tables) in the database –Primary key – a field (or group of fields) that uniquely identifies a given entity in a table –Foreign key – a primary key of one table that appears an attribute in another table and acts to provide a logical relationship among the two tables

7-9 Keys and Relationships Potential relational database for Coca-Cola

7-10 Relational Database Advantages Database advantages from a business perspective include –Increased flexibility –Increased scalability and performance –Reduced information redundancy –Increased information integrity (quality) –Increased information security

7-11 Increased Flexibility A well-designed database should: –Handle changes quickly and easily –Provide users with different views –Have only one physical view Physical view – deals with the physical storage of information on a storage device –Have multiple logical views Logical view – focuses on how users logically access information

7-12 Increased Scalability and Performance A database must scale to meet increased demand, while maintaining acceptable performance levels –Scalability – refers to how well a system can adapt to increased demands –Performance – measures how quickly a system performs a certain process or transaction

7-13 Reduced Information Redundancy Databases reduce information redundancy –Redundancy – the duplication of information or storing the same information in multiple places Inconsistency is one of the primary problems with redundant information

7-14 Increase Information Integrity (Quality) Information integrity – measures the quality of information Integrity constraint – rules that help ensure the quality of information –Relational integrity constraint – rule that enforces basic and fundamental information-based constraints –Business-critical integrity constraint – rule that enforce business rules vital to an organization’s success and often require more insight and knowledge than relational integrity constraints

7-15 Increased Information Security Information is an organizational asset and must be protected Databases offer several security features including: –Password – provides authentication of the user –Access level – determines who has access to the different types of information –Access control – determines types of user access, such as read-only access

7-16 Database Management Systems Database management systems (DBMS) – software through which users and application programs interact with a database

7-17 Database Management Systems Four components of a DBMS

7-18 Data Definition Component Data definition component – creates and maintains the data dictionary and the structure of the database The data definition component includes the data dictionary –Data dictionary – a file that stores definitions of information types, identifies the primary and foreign keys, and maintains the relationships among the tables

7-19 Data Definition Component Data dictionary essentially defines the logical properties of the information that the database contains

7-20 Data Manipulation Component Data manipulation component – allows users to create, read, update, and delete information in a database A DBMS contains several data manipulation tools: –View – allows users to see, change, sort, and query the database content –Report generator – users can define report formats –Query-by-example (QBE) – users can graphically design the answers to specific questions –Structured query language (SQL) – query language

7-21 Data Manipulation Component Sample report using Microsoft Access Report Generator

7-22 Data Manipulation Component Sample report using Access Query-By-Example (QBE) tool

7-23 Data Manipulation Component Results from the query in Figure 7.6

7-24 Data Manipulation Component SQL version of the QBE Query in Figure 7.6

7-25 Application Generation and Data Administration Components Application generation component – includes tools for creating visually appealing and easy-to- use applications Data administration component – provides tools for managing the overall database environment by providing faculties for backup, recovery, security, and performance IT specialists primarily use these components

7-26 Integrating Information among Multiple Databases Integration – allows separate systems to communicate directly with each other –Forward integration – takes information entered into a given system and sends it automatically to all downstream systems and processes –Backward integration – takes information entered into a given system and sends it automatically to all upstream systems and processes

7-27 Integrating Information among Multiple Databases Forward integration

7-28 Integrating Information among Multiple Databases Backward integration

7-29 Integrating Information among Multiple Databases Building a central repository specifically for integrated information

7-30 OPENING CASE STUDY QUESTIONS It Takes A Village to Write an Encyclopedia 1.Identify the different types of entity classes that might be stored in Wikipedia’s database 2.Explain why database technology is so important to Wikipedia’s business model 3.Explain the difference between logical and physical views and why logical views are important to Wikipedia’s customers

7-31 CHAPTER SEVEN CASE Hotcourses Increases Revenues by 60 Percent Hotcourses is one of the hottest new e- businesses in London Offers a comprehensive online educational marketplace After two years of operation the company estimates revenues for 2003 between $100 and $500 million

7-32 Chapter Seven Case Questions 1.Identify the different types of entity classes and attributes potentially maintained in the Hotcourses database 2.Describe the two different ways that employees at Hotcourses might access the information in their databases 3.Create two questions that a manager at Hotcourses could turn into queries and run against a database to discover business intelligence

7-33 Chapter Seven Case Questions 4.List several useful reports management would like to see based on data in the database 5.Would different entity types be required for different countries?