1. Fundamentals & Ethics of Information Systems IS 201
Chapter 4
Organizing Data and Information
Databases and Database Management Systems
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Learning Objectives
Define general data management concepts and terms
Highlight the advantages of the database approach to data management
Describe the relational database model and outline its basic features
Identify the common functions performed by all database management systems and identify popular user database management systems
Identify and briefly discuss current database applications
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Chapter Overview
Why Learn About Database Systems?
What is a Database?
The Hierarchy of Data
The Database Approach
Data Modeling
Database Management Systems (DBMS)
Data Warehouses, Data Marts, and Data Mining
Business Intelligence
Online Analytical Processing (OLAP)
Object-Oriented Databases
Summary
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4. 1. Why Learn About Database Systems?
Database systems process and organize large amounts of data
Database systems organize all transactions and services in our societies
Examples
Student registration database system
Bank accounts database system
Hospital patient record database system
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2. What is a Database?
Database (DB): an organized collection of data
Database Management System (DBMS): group of programs to:
Manages and Manipulates database
Provides an interface between database and user and other application programs
Database administrator (DBA): skilled IS professional who directs all activities related to an organization’s database
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Data Management
Without data and the ability to process it, an organization could not successfully complete most business activities
Data consists of raw facts
For data to be transformed into useful information, it must first be organized in a meaningful way
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3. The Hierarchy of Data
Bit (a binary digit): a circuit that is either on or off
Byte: eight bits
Character: basic building block of information
Each byte represents a character
Can be an uppercase letter, lowercase letter, numeric digit, or special symbol
Field: typically a name, number, or combination of characters that describes an aspect of a business object or activity
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8. The Hierarchy of Data (cont.)
Record: a collection of related data fields
File: a collection of related records
Database: a collection of integrated and related files
Hierarchy of data: bits, characters, fields, records, files, and databases
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9. The Hierarchy of Data (cont.)
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10. Data Entities, Attributes, and Keys
Entity: a generalized class of people, places, or things for which data is collected, stored, and maintained (students, teachers, employees, …)
Attribute: characteristic of an entity
Data item (value): value of an attribute
Primary key: field or set of fields that uniquely identifies the record
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11. Data Entities, Attributes, and Keys (cont.)
Keys and Attributes
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4. The Database Approach
Traditional approach to data management: separate data files are created for each application
Results in data redundancy (duplication)
Data redundancy conflicts with data integrity
Database approach to data management: pool of related data is shared by multiple applications
Significant advantages over traditional approach
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13. The Database Approach to Data Management
DB Approach
The Database Approach to Data Management
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14. Advantages of the Database Approach
DB Approach (cont.)
Advantages of the Database Approach
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15. Advantages of the Database Approach (continued)
DB Approach (cont.)
Advantages of the Database Approach (continued)
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16. Disadvantages of the Database Approach
DB Approach (cont.)
Disadvantages of the Database Approach
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5. Data Modeling
Data model: a diagram of data entities and their relationships
Entity-relationship (ER) diagrams: data models that use basic graphical symbols to show the organization of and relationships between data entities
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18. An Entity-Relationship (ER) Diagram for a Customer Order Database
Data Modeling (cont.)
Entity
Relationship
An Entity-Relationship (ER) Diagram for a Customer Order Database
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Data Modeling (cont.)
A Simplified ER Diagram Showing the Relationship Between the Manager, Department, and Project Tables
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DB Design
Building a database requires two types of designs
Logical design
Abstract model of how data should be structured and arranged to meet an organization’s information needs
Physical design
Fine-tunes the logical database design for performance and cost considerations
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Building DB
When building a database, consider:
Content: What data should be collected, at what cost?
Access: What data should be provided to which users and when?
Logical structure: How should data be arranged to make sense to a given user?
Physical organization: Where should data be physically located?
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Database Models
Flat file Databases
Plain text files usually contain one record per line
Fields can be separated by delimiters such as comma or tab characters
Relational Databases
2-D tables
Each row represents a record
Each column represents an attribute
Object oriented Databases
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23. The Relational Database Model
Relational model: all data elements are placed in two-dimensional tables, which are the logical equivalent of files
In the relational model
Each table is an entity
Each row of a table represents a record
Columns of the table represent attributes
Domain: the allowable values for data attributes
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24. The Relational Database Model (cont.)
A Relational Database Model
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Manipulating Data
Selecting: eliminates rows according to criteria
Projecting: eliminates columns in a table
Joining: combines two or more tables
Linking: relates or links two or more tables using common data attributes
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26. Linking Data Tables to Answer an Inquiry
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27. 6. Database Management Systems (DBMS)
DBMS: a group of programs used as an interface between a database and application programs or a database and the user
Creating and implementing the right DBMS ensures that the database will support both business activities and goals
user
Application
DBMS DB
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28. Overview of Database Types
Single user
Only one person can use the database at a time
Examples: Access, FileMaker, and InfoPath
Multiple user
Allows dozens or hundreds of people to access the same database system at the same time
Examples: Oracle, Sybase, and IBM
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DB schema
Schema: description of the entire database
Large database systems typically use schemas to define the tables and other database features associated with a person or user
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Creating a DB schema
Data Definition Language (DDL)
Collection of instructions/commands that define and describe data and data relationships in a database
Data dictionary: a detailed description of all the data used in the database
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31. Using DDL to define schema
Using a Data Definition Language to Define a Schema
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32. A Typical Data Dictionary Entry
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33. Storing and Retrieving Data
When an application requests data from the DBMS, the application follows a logical access path
When the DBMS goes to a storage device to retrieve the requested data, it follows a path to the physical location (physical access path) where the data is stored
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34. Storing and Retrieving Data (cont.)
Logical and Physical Access Paths
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35. Manipulating Data and Generating Reports
Query-By-Example (QBE): a visual approach to developing database queries or requests
Data Manipulation Language (DML): commands that manipulate the data in a database
Structured Query Language (SQL): ANSI standard query language for relational databases
Database programs can produce reports, documents, and other outputs
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36. Examples of SQL Commands
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37. Database Administration
Database administrator (DBA): directs or performs all activities to maintain a database environment
Designing, implementing, and maintaining the database system and the DBMS
Establishing policies and procedures
Employee training
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Popular DBMS
Popular DBMSs for end users: Microsoft Access and FileMaker Pro
Entire market includes databases by IBM, Oracle, and Microsoft
Examples of open-source database systems: PostgreSQL and MySQL
Many traditional database programs are now available on open-source operating systems
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Selecting a DBMS
Important characteristics of databases to consider
Size of the database
Cost of the system
Number of concurrent users
Performance
Ability to be integrated with other systems
Vendor considerations
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40. Using DBMS with Other Software
DBMS are often used with other software packages or the Internet
A DBMS can act as a front-end application or a back-end application
Front-end application: interacts with users
Back-end application: interacts with applications
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41. Linking Databases to the Internet
Linking databases to the Internet is important for many organizations and people
Allows people to access and manipulate a number of traditional databases at the same time through the Internet
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42. 7. Data Warehouses and Data Marts
Data warehouse: collects business information from many sources in the enterprise
Data mart: a subset of a data warehouse
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43. J. Berri Chapter3 – Binary Number System Slide 43
Data mining
Data mining: an information-analysis tool for discovering patterns and relationships in a data warehouse or a data mart
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44. Elements of data warehouse
Elements of a Data Warehouse
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45. 8. Business Intelligence
Business intelligence (BI): gathering the right information in a timely manner and usable form and analyzing it to have a positive impact on business and enterprise
Turns data into useful information that is then distributed throughout an enterprise
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46. Business Intelligence (cont.)
Competitive intelligence: aspect of business intelligence limited to information about competitors and the ways that knowledge affects strategy, tactics, and operations
Counterintelligence: steps an organization takes to protect information sought by “hostile” intelligence gatherers
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47. 9. Online Analytical Processing (OLAP)
Software that allows users to explore data from a number of different perspectives
Comparison of OLAP and Data Mining
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48. 10. Object-Oriented Databases
Stores both data and its processing instructions
Method: a procedure or action
Message: a request to execute or run a method
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11. Summary
Hierarchy of data: bits, characters, fields, records, files, and databases
Entity: generalized class of people, places, or things for which data is collected, stored, and maintained
Attribute: characteristic of an entity
Data model: diagram of data entities and relationships
Relational model: describes data in which all elements are placed in two-dimensional tables called relations
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Summary (cont.)
A database management system (DBMS) is a group of programs used as an interface between:
Database and application programs
Database and the user
Data warehouse: database that collects business information from all aspects of a company’s processes, products, and customers
Data mining: an information-analysis tool for discovering patterns and relationships in a data warehouse
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