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CHAPTER 7

Storing Organizational Information - Databases

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Learning Outcomes

Define the fundamental concepts of the relational database model

Evaluate the advantages of the relational database model

Compare operational integrity constraints and business-critical integrity constraints

Describe the role and purpose of a database management system

List and describe the four components of a database management system

Describe the two primary methods for integrating information across multiple databases

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Overview

Information is stored in databases Database – maintains information about

various types of objects (inventory), events (transactions), people (employees), and places (warehouses)

Almost every business decision isbased on information

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Database Models

Hierarchical database – stores related information in terms of predefined categorical relationships in a “tree-like” fashion

Network database – used by a network installation tool to allocate and track network resources

Relational database model – stores information in the form of logically related two-dimensional tables

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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 Entity includes Dave’s Sub Shop and Pizza Palace entities

[Figure 2.6 – CUSTOMER] Entity class (table) – a collection of similar entities

Entity classes include CUSTOMER, ORDER, ORDER LINE, DISTRIBUTOR, and PRODUCT

Attributes (fields, columns) – characteristics or properties of an entity class The columns in each table contain the attributes Attributes for CUSTOMER include Customer ID, Customer

Name, Contact Name, and Phone

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Keys and Relationships

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

A relational database for Coca-Cola

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Relational Database Advantagesfrom a business perspective Increased flexibility Increased scalability and performance Reduced information redundancy Increased information integrity (quality) Increased information security

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Increased Flexibility

A well-designed database should: Handle changes quickly and easily Provide users with different views A database has only one physical view

Physical view – deals with the physical storage of information on a storage device such as a hard disk

A database can have multiple logical views Logical view – focuses on how users logically

access information to meet particular business needs

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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

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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

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Increase Information Integrity

Information integrity – a measure of the quality of information

Integrity constraints – rules that help ensure the quality of information Operational integrity constraints – rules that

enforce basic and fundamental information-based constraints

Business-critical integrity constraints – rules that enforce business rules vital to an organization’s success and often require more insight and knowledge than operational integrity constraints

Users cannot create an orderfor a nonexistent customer

Product returns are not accepted forfresh product 15 days after purchase

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Increased Information Security

Information is an organizational asset and must be protected

Databases offer several security features including: Passwords – provide authentication of the

user Access levels – determine who has access to

the different types of information Access controls – Determine types of user

access, such as read-only access

Database management systems (DBMS) – software through which users and application programs interact with a database

Four components of a DBMS

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Data Definition Component

helps create and maintain the data dictionary and the structure of the database

Data dictionary – a file that stores definitions of information types, identifies the primary and foreign keys, and maintains the relationships among the tables

The data dictionary essentially defines the logical properties of the information that the database contains

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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: Views – Allows users to see, change, sort, and

query the database content Report generators Query-by-example (QBE) Structured query language (SQL)

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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

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Integrating Information among Multiple Databases Organizations typically maintain multiple systems,

each with its own database 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

Building a central repository specifically for integrated information

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Opening Case Study Questions - Searching for Revenue - Google

1. Identify the different types of entity classes that might be stored in Google’s indexing database

2. Explain why database technology is so important to Google’s business model

3. Explain the difference between logical and physical views and why logical views are important to Google’s employees