Databases and Information Management ITSC 1401, Intro to Computers Instructor: Glenda H. Easter.

Databases and Databases and Information Management Information Management

ITSC 1401, Intro to Computers

Instructor: Glenda H. Easter

Databases and Information Management

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Chapter 10 ObjectivesChapter 10 Objectives

Explain why data and information are important to an organization

Identify data maintenance techniques

Differentiate between file processing and databases

Discuss the advantages of using a database management system (DBMS)


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Objectives Objectives (Continued)(Continued)

Describe the characteristics of relational and object-oriented databases

Explain how to use a query language

Discuss the responsibilities of the data and database administrators

Describe the various types of information systems


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Data and InformationData and Information

DataCollection of items such as words, numbers, images, and sounds that are not organized and have little meaning individually

InformationData that is organized


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Database - AdvantagesDatabase - Advantages

Data IntegrityData AccuracyData IntegrationControl of

Data dependenceData redundancy

Data Security


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What Is a Database?What Is a Database?

A database is a collection of data files treated as a unit for information retrieval.

When data consists of logical files and records, it is said to be “integrated.”

A collection of “integrated” data is defined as a database.


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Data Storage HierarchyData Storage Hierarchy

Bits

Character (Bytes)

Field

Record

File

Database


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Data Storage Hierarchy Data Storage Hierarchy (Continued)(Continued)

Bit: Eight bits make one byte or one character.Character: One separate byte that can be a number, a letter, special symbol, or a spacebar.Fields: A group of related characters.Record: A group of related fields.File: A group of related records.Database: A group of related files.


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Hierarchy of Data Hierarchy of Data (Continued)(Continued)

Data typesTextNumericCurrencyDateMemoHyperlinkObject


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Hierarchy of Data Hierarchy of Data (Continued)(Continued)

Key field (primary key)

Data file (file)

Records


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Maintaining DataMaintaining Data

Adding Records

Changing Records

Deleting Records


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Maintaining DataMaintaining Data

Adding Records


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Maintaining Data Maintaining Data (Continued)(Continued)

Changing Records


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Maintaining Data Maintaining Data (Continued)(Continued)

Deleting Records


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Data ValidationData Validation

Comparing data to a set of rules to determine if the data is accurate.


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Data Validation Data Validation (Continued)(Continued)

Alphabetic/numeric check

Completeness check

Range check

Consistency check

Check digit


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File Processing Versus File Processing Versus DatabasesDatabases

File Processing SystemsEach department has its own set of files

Disadvantages• Data redundancy

• Isolated data


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File Processing SystemsFile Processing Systems


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The Database ApproachThe Database Approach

Many applications use the data in a single shared database


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AdvantagesReduced data redundancy

Improved data integrity

Shared data

Reduced development time

Easier reporting

Disadvantages: Cost and vulnerability

Database Approach (Advantages Database Approach (Advantages and Disadvantages)and Disadvantages)


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Advantages of DatabasesAdvantages of Databases

Data Sharing: Information from one department of an organization can be shared with others.

Data Security: Passwords can be used to prevent access to databases from unauthorized users. This might involve requiring passwords to access data, and making data read-only to certain users.


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Advantages of DatabasesAdvantages of Databases(Continued)(Continued)

Eliminates Data Redundancy or eliminates the repetition of the same data in different files. There are fewer files to manage. If several departments have access to the same database files, management of resources is more efficient. Data Integrity deals with the consistency of information in all applications. Changes made in data will be consistent throughout all related files.


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Disadvantage of Databases Disadvantage of Databases (Data Dependence)(Data Dependence)

Data dependence could result in incompatible information.

This might occur when data files from different applications are incompatible and cannot be linked.


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Processing Environment –vs- Processing Environment –vs- the Database Environmentthe Database Environment


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The Database ApproachThe Database Approach


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File Processing –vs- DatabaseFile Processing –vs- Database


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Database Management SystemsDatabase Management Systems

Software or a set of programs designed to control access to the database and manage data resources efficiently

Available for various sizes and types of computers


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DBMS SoftwareDBMS Software

DDLDMLQuery LanguageReport Generator

SchemaField Name

Field LengthType

Query: Who was the first female astronaut?


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The Parts of Database The Parts of Database Management Software (DBMS)Management Software (DBMS)

To produce a printed report or search for specific field values, you have to know which type of data is stored in each field. Database management system software is made of:

data dictionary languagedata manipulation languagequery language


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Data DictionaryData Dictionary

This contains a description of the structure of the data used in the database. It describes:

field names

size of fields

type of data to be stored in field (text, number, logical, date, image)


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Data DictionaryData Dictionary

Stores data about each file in the database and each field within those files


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Data Maintenance and Data Maintenance and RetrievalRetrieval

Query

Query language


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Query LanguageQuery LanguageThis is an easy-to-use language understandable to most users.The most widely used query language is Structured Query Language (SQL).This is made up of commands which direct the computer to fulfill the access needs of the user in searching, displaying, updating, and printing records in a database file.

“find last name=‘Chicago’”.Partial specification of a field using a ‘wildcard’ character: “find author=johns*”Queries are usually case sensitive.


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Query-by-example (QBE)Query-by-example (QBE)


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Forms (Data Entry Forms)Forms (Data Entry Forms)


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Data Manipulation LanguageData Manipulation Language

Microcomputer programs generally have a set of commands (either command-line interface or menu-based).

These commands enable the user to create a database (adding fields or certain data types) and also to add, delete, and modify records and query and generate reports.


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The Report GeneratorThe Report Generator

Microcomputer file management systems allow the user to arrange the report by clicking fields, graphic elements, and page headings dragging them into place and selecting a format for each.


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Report Generator (Report Report Generator (Report Writer)Writer)


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Using Database SoftwareUsing Database SoftwareFinding information

browse viewlist viewqueriesStructured Query Language (SQL)

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Learn SQL online at “Introduction to Structured Query Language,” an online tutorial.

http://w3.one.net/~jhoffman/sqltut.htm


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Database SecurityDatabase Security

Passwords

User Call-Back Systems

Routine Backups


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Data SecurityData Security

Data SecurityAccess privileges

Examples• Read-only

• Full-update


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Security of DatabasesSecurity of Databases

Since so many users are accessing electronic databases, keeping them secure has been a very vital issue.Constant efforts must be made to keep users from tampering with or misusing databases. One major concern is with preventing unauthorized users from gaining access to a database and launching a computer virus that could invade programs and databases, as well as destroy data.


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Protecting Your PrivacyProtecting Your Privacy

Security of databases is becoming a bigger issue as technology advances.Security features include having the physical presence of guards in areas where confidential databases are maintained. Protective measures include requiring identification checks, and storing backup tapes of disks of all valuable information in another location.


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Backup and RecoveryBackup and Recovery

Make backups (copies) on a regular basis

LogsBefore image

After image

Recovery utilitiesRollback

Rollforward


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Types of Database SoftwareTypes of Database Software

File Management ProgramsDatabase Management Systems

HierarchicalNetworkRelationalObject-Oriented


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File Management or WINFILEFile Management or WINFILEC:\

Games

WordProc

Personal

Diary

School

DataBase

CDs

BBCards

Recipes

Drawing

Photos


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File Management ProgramsFile Management Programs

File Management Programs can work with only one file at a time.File management programs are less complex and inexpensive.They create flat files.

Flat files can access records either sequentially, randomly, or sorted.Flat files cannot be linked to data in other files. This is a major disadvantage of them.They do not use key fields or indexes to refer to other files.


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Database management systems can work with several separate files at a time.The database management system uses one of the four database structures to link files:

hierarchical databasesnetwork databasesrelational databasesobject-oriented databases


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Relational DatabasesRelational Databases

Relation or table (file)

Row (record)

Attribute or column (field)

Relationships


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This is the most flexible type of database organization.

Elements are stored in different tables which consist of rows and columns.

A table is called a relation. All related tables must have a common data item or a key field.


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Structured Query Language (SQL)Keywords and rules used to implement relational algebra operations


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Database Management Systems Database Management Systems (Object-Oriented)(Object-Oriented)

SoundVideoText

GraphicsAnimation


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Relational Databases Relational Databases (Continued)(Continued)


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A common field existing

in any two tables creates

a relationship between

the tables. For instance, a

Customer ID Number field

in both a customers table

and an orders table links the

two tables. The relational

database structure is the

most prevalent in today's

organizations


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Object-Oriented DatabasesObject-Oriented Databases

Objects contain both data and the activities to read or manipulate the data

ExamplesMultimedia database

Groupware database

Computer-aided design

Hypertext database


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Object-Oriented DatabasesObject-Oriented Databases

Object-Oriented Databases contain graphics and/or sound.

Object-Oriented databases concentrate on the use of objects in the database and provide operations on those objects.


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Object-Oriented Databases -– Object-Oriented Databases -– Hypertext Databases Hypertext Databases


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Database Management Systems Database Management Systems (Hierarchical)(Hierarchical)

Parent Elements

Child Elements


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Hierarchical DatabasesHierarchical Databases

This type of organization is similar to a hierarchical chart of a business organization.Fields or records in a hierarchical database are structured in nodes.The node itself can be a parent or a child to another node. Each segment can only have one parent.


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Hierarchical DatabasesHierarchical Databases

H iera rch ia l D a tab ases

C h ild C h ild

C h ild /P aren t

C h ild C h ild

C h ild /P aren t

C h ild C h ild

C h ild /P aren t

P aren t


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Network DatabasesNetwork Databases

Network databases have a structure similar to hierarchical databases, except child nodes or elements can have more than one parent (node) or element.

For this reason, the network database may provide more than one way to reach the same element.

Additional connections between parent nodes and child nodes are called pointers.


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Database Management Systems Database Management Systems (Network)(Network)

Parent ElementsParent ElementsChild ElementsChild Elements


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Database AdministrationDatabase Administration

Role of the Data and Database Administrators

Designing databases

Creating and maintaining data dictionary

Security

Performance

Backup and recovery


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Database Administration Database Administration (Continued)(Continued)

Role of the userBecome familiar with the data

Specify additions to the database


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Creating and Using a DatabaseCreating and Using a Database

Defining the Structure

Entering Data

Designing a Form


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DBMS TipsDBMS Tips

Design Carefully

Define Data

Use Forms or Templates

Use Report Writer Features

Use Queries

Use Relational Characteristics


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Database Design GuidelinesDatabase Design Guidelines

Database Design GuidelinesCareful design to make it easier for users to query and modify the database and create reports


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Creating and Using a DatabaseCreating and Using a Database

Database applications allow non-programmers to use the database through pre-written, general-purpose programs.In a database, a field must be defined with a record number, a name, a field length, and a type.Some databases allow calculation fields which include formulas.Forms can be designed to make data entry easy or to display on those fields that a user needs to see.


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Database Design GuidelinesDatabase Design Guidelines


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Qualities of Valuable Qualities of Valuable InformationInformation

Accurate information

Verifiable

Timely information

Organized information

Meaningful information

Cost-effective information


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How Managers Use How Managers Use InformationInformation

Planning

Organizing

Leading

Controlling


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Qualities of Valuable Qualities of Valuable InformationInformation

Levels of UsersExecutive management

Middle management

Operational management

Nonmanagement employees


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Level of UsersLevel of Users


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Types of Information SystemsTypes of Information Systems

Information systemsCollection of hardware, software, data, people and procedures designed to generate information


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Office Information SystemsOffice Information Systems

Enhance workflow

Facilitate communications

Office automation


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Transaction Processing Transaction Processing SystemsSystems

Capture information generated during and organization’s day-to-day transactionsRecording an activityConfirming an action or triggering a responseMaintaining dataOnline transaction processing (OLTP)


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Management Information Management Information SystemsSystems

Generates accurate, timely, and organized information

Management reporting system (MRS)• Detailed information

• Summary information

• Exception information


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Decision Support SystemsDecision Support Systems

Help users reach a decision

Internal data sources

External data sources

Executiveinformation systems


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Executive Information System Executive Information System (EIS)(EIS)


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Expert SystemsExpert Systems

Capture and store knowledge of human experts

Imitates human reasoning and decision-making process

Knowledge base

Inference rules

Artificial intelligence (AI)


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Databases

Database Concepts: The EssentialsWhat’s a good Database System?Using Database SoftwareTypes of Database ProgramsThe Internet Connection: Going Public with Data


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Database Concepts:The Essentials

Databasecollection of information stored in an

organized waycan consist of one or more files

Database filemade up of recordsunit of information about something


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Database Concepts:The Essentials

Recordsorganized into distinct fields

Fieldseparate area to store a certain type of

information

D

Explore the world of computer databases at LookSmart’s Databases page.

http://databases.miningco.com/

http://databases.miningco.com/


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Database Management Systems - enables users to create database tables and provides multiple users with access to data.


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Types of fields

(Laura’s record contains several fields)(One file is made up of Laura’s, Bill’s and Peter’s records)

Databases and Information Management ITSC 1401, Intro to Computers Instructor: Glenda H. Easter.

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Transcript of Databases and Information Management ITSC 1401, Intro to Computers Instructor: Glenda H. Easter.