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1 CHAPTER 7 Storing Organizational Information - Databases.

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1 1 CHAPTER 7 Storing Organizational Information - Databases

2 2 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

3 3 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 is based on information

4 4 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

5 5 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

6 6 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

7 A relational database for Coca-Cola

8 8 Relational Database Advantages from a business perspective Increased flexibility Increased scalability and performance Reduced information redundancy Increased information integrity (quality) Increased information security

9 9 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

10 10 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

11 11 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

12 12 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 order for a nonexistent customer Product returns are not accepted for fresh product 15 days after purchase

13 13 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

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

15 Four components of a DBMS

16 16 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

17 17 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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20 20 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

21 21 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

22 Building a central repository specifically for integrated information

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24 24 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


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