Chapter 7: Database Systems Succeeding with Technology: Second Edition.

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


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


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


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


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


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


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)


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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?


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


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

Chapter 7: Database Systems Succeeding with Technology: Second Edition.

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