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Chapter 7

Chapter 7. Storing Organizational Information - Databases. Learning Outcomes. 7.1 Define the fundamental concepts of the relational database model 7.2 Evaluate the advantages of the relational database model

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Chapter 7

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  1. Chapter 7 Storing Organizational Information - Databases

  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

  3. Learning Outcomes 7.4 Describe 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

  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)

  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

  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. 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

  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

  9. Keys and Relationships • Potential relational database for Coca-Cola

  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

  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

  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

  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

  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

  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 • Accesslevel – determines who has access to the different types of information • Accesscontrol – determines types of user access, such as read-only access

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

  17. Database Management Systems • Four components of a DBMS

  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

  19. Data Definition Component • Data dictionary essentially defines the logical properties of the information that the database contains

  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 • Reportgenerator – users can define report formats • Query-by-example (QBE) – users can graphically design the answers to specific questions • Structured query language (SQL) – query language

  21. Data Manipulation Component • Sample report using Microsoft Access Report Generator

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

  23. Data Manipulation Component • Results from the query in Figure 7.6

  24. Data Manipulation Component • SQL version of the QBE Query in Figure 7.6

  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

  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

  27. Integrating Information among Multiple Databases • Forward integration

  28. Integrating Information among Multiple Databases • Backward integration

  29. Integrating Information among Multiple Databases • Building a central repository specifically for integrated information

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

  31. CHAPTER SEVEN CASEHotcourses 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

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

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

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