Upload
darlene-hines
View
227
Download
0
Tags:
Embed Size (px)
Citation preview
Chapter 7: Database Systems
Succeeding with Technology: Second Edition
Succeeding with Technology 2
Objectives
Understand basic data management concepts
Describe database models and characteristics
Discuss the different types of database management systems and their design and use by individuals and organizations
Succeeding with Technology 3
Objectives (continued)
Describe how organizations use database systems to perform routine processing, provide information and decision support, and how they use data warehouses, marts, and mining
Discuss additional database systems, including distributed systems and Web-based systems
Describe the role of the database administrator (DBA) and database policies and security practices
Succeeding with Technology 4
Basic Data Management Concepts Database
A collection of data organized to meet users’ needs Database management system (DBMS)
Software used to access database Database system
Comprised of database, DBMS, and application programs
Succeeding with Technology 5
Data Management for Individuals and Organizations Individuals use databases to
Develop monthly budgets Store phone numbers and addresses Keep track of important dates Keep track of valuables for possible insurance claim Get information about organizations such as
hospitals
Succeeding with Technology 6
The Hierarchy of Data
Field Name, number, or combination of characters that
describes some aspect of an object Record
Collection of related fields File
Collection of related records Database
Collection of integrated and related files
Succeeding with Technology 7
Succeeding with Technology 8
Data Entities, Attributes, and Keys Entity
Generalized class of people, places, or things for which data is collected, stored, and maintained
Attribute Characteristic of an entity For example, employee number or last name
Key Field in a record used to identify the record Primary key
Uniquely identifies the record
Succeeding with Technology 9
Succeeding with Technology 10
The Database Approach to Data Management
Database approach Multiple application programs share a pool of related
data Increased flexibility in the use of data Requires a database management system (DBMS)
Succeeding with Technology 11
Succeeding with Technology 12
Succeeding with Technology 13
Organizing Data in a Database Questions to be asked when building a database
What data is to be collected and at what cost
What data is to be provided to which users when appropriate
How is the data to be arranged so that it makes sense
Where is the data to be physically located
Who is responsible for maintaining an accurate database system
Succeeding with Technology 14
The Relational Database Model Purpose
To describe data using a standard tabular format All data elements are placed in two-dimensional
tables called relations Selecting
Choosing data based on certain criteria Joining
Combining two or more tables
Succeeding with Technology 15
Succeeding with Technology 16
Succeeding with Technology 17
Data Analysis
Evaluating data to identify problems with content of database
Normalization Process of correcting data problems or anomalies Breaking a table into two or more tables in order to
correct the data problem or anomaly
Succeeding with Technology 18
Succeeding with Technology 19
Succeeding with Technology 20
Object-Oriented Databases
Use the same overall approach as objected-oriented programming
Data and processing instructions are stored in the database
Offer the ability to reuse and modify existing objects
Succeeding with Technology 21
Succeeding with Technology 22
Database Characteristics
Database size or amount Depends on the number of records or files in the
database
Volatility of data
Measure of the changes typically required in a given period of time
Immediacy Measure of how rapidly changes must be made to
data
Succeeding with Technology 23
Database Management Systems Creating and implementing the right database
system involves Determining how data is stored and retrieved How people will see and use the database How the database will be created and maintained How reports and documents will be generated
Succeeding with Technology 24
Overview of Database Types Flat file
Used to store and manipulate a single table or file Single User
Only one person can use the database at any time Multiuser
Networked computer systems need multiuser DBMSs
Succeeding with Technology 25
Overview of Database Types (continued)
General-purpose database
Can be used for a large number of applications
Special-purpose database
Designed for a limited number of applications
Open-Source database systems
PostgreSQL, MySQL
Succeeding with Technology 26
Database Design Numeric field
Contains numbers that can be used in making calculations
Alphanumeric Characters or numbers that will not be manipulated
Date Can be sorted or even used in computations
Logical piece of data Contains items, such as “yes” or “no”
Computed field Determined from other fields
Succeeding with Technology 27
Using Databases with Other Software Front-end application
One that directly interacts with people or users Back-end application
Interacts with other programs or applications
Succeeding with Technology 28
Data Accuracy and Integrity
Data integrity Data stored in the database is accurate and up to
date Garbage in, garbage out (GIGO)
Inaccurate data input results in inaccurate output Database management systems
Must be programmed to detect and eliminate data inaccuracies
Succeeding with Technology 29
Creating and Modifying a Database Schema
Outline of the logical and physical structure of the data and relationships among the data
Data definition language (DDL) Collection of instructions and commands
Data dictionary Detailed description of all data used in the database
Succeeding with Technology 30
Succeeding with Technology 31
Creating and Modifying a Database (continued) Typical uses of a data dictionary
Provide a standard definition of terms and data elements
Assist programmers in designing and writing programs
Simplify database modification
Succeeding with Technology 32
Manipulating Data and Generating Reports
Data manipulation language (DML) Allows users to
Access, modify, and make queries Generate reports
Query by example (QBE) Makes manipulating databases much easier and
faster Structured Query Language (SQL)
Standardized data manipulation language
Succeeding with Technology 33
Database Backup and Recovery Database backup
A copy of all or part of the database Database recovery
Returning database to original, correct condition if it has crashed or has been corrupted
Redundant array of independent disks (RAID) Used to store duplicate data on multiple disks
Storage area network (SAN) Used to connect multiple storage devices on high-
speed networks
Succeeding with Technology 34
Using Database Systems in Organizations
Organizations need to process routine transactions Routine processing activities
Pay employees Send out bills to maintain a healthy cash flow Send out a monthly newsletter Pay suppliers for parts and raw materials
Information and decision support Valuable tool to support decision making
Succeeding with Technology 35
Data Warehouses, Data Marts, and Data Mining
Data warehouse Holds important information from a variety of
sources Usually a subset of multiple databases
Data mart Small data warehouse Often developed for a specific person or purpose
Succeeding with Technology 36
Data Warehouses, Data Marts, and Data Mining (continued) Data mining
Extracting information from a data warehouse or a data mart
Business intelligence Business use of use data mining can help increase
efficiency, reduce costs, or increase profits
Succeeding with Technology 37
Succeeding with Technology 38
Database Trends – Distributed Databases Distributed database
Also called a virtualized database Actual data may be spread across several
databases at different locations Allow more users direct access at different user
sites Replicated database
Database that holds a duplicate set of frequently used data
Succeeding with Technology 39
Succeeding with Technology 40
Managing Databases – Database Administration Database administrators are responsible for
Overall design and coordination of the database Development and maintenance of schemas Development and maintenance of the data
dictionary Implementation of the DBMS
Succeeding with Technology 41
Database Use, Policies, and Security End-user computing
Development and use of application programs by noncomputer-systems professionals
End-user computing issues
What data can users read, update, or write in a database?
What procedures are needed to guarantee proper database use and security?
Succeeding with Technology 42
Summary
Data Organized into a hierarchy
Entity Generalized class of objects for which data is
collected Database designers
Can use a data model to show relationships among data
Object-oriented model Stores data as objects
Succeeding with Technology 43
Summary (continued)
DBMS Group of programs used as an interface between a
database and application programs Schemas
Entered into the computer via a data definition language (DDL)
Most organizations use a database system to Send out bills, pay suppliers Print paychecks Perform other routine transaction processing
activities