SESSION 7SESSION 7

MANAGINGMANAGING

DATA DATA

RESOURCESRESOURCES

File Organization Terms and Concepts

Field:Field: Group of words or a complete Group of words or a complete numbernumber

Record:Record: Group of related fieldsGroup of related fields

File:File: Group of records of same typeGroup of records of same type

Database:Database: Group of related filesGroup of related files

ORGANIZING DATA IN A TRADITIONAL FILE ENVIRONMENT

Data Hierarchy in a Computer System

Figure 7-1

File Organization Terms and Concepts

ORGANIZING DATA IN A TRADITIONAL FILE ENVIRONMENT

Entity:Entity: Person, place, thing, event about Person, place, thing, event about which information is maintainedwhich information is maintained

Attribute:Attribute: Description of a particular entity Description of a particular entity

Key field:Key field: Identifier field used to retrieve, Identifier field used to retrieve, update, sort a recordupdate, sort a record

File Organization Terms and Concepts

ORGANIZING DATA IN A TRADITIONAL FILE ENVIRONMENT

Figure 7-2

Entitities and AttributesFile Organization Terms and Concepts

ORGANIZING DATA IN A TRADITIONAL FILE ENVIRONMENT

Data redundancyData redundancy

Program-Data dependenceProgram-Data dependence

Lack of flexibilityLack of flexibility

Poor securityPoor security

Lack of data-sharing and availabilityLack of data-sharing and availability

Problems with the Traditional File Environment

ORGANIZING DATA IN A TRADITIONAL FILE ENVIRONMENT

THE DATABASE APPROACH TO DATA MANAGEMENT

• Creates and maintains databasesCreates and maintains databases

• Eliminates requirement for data definition Eliminates requirement for data definition statementsstatements

• Acts as interface between application Acts as interface between application programs and physical data filesprograms and physical data files

• Separates logical and design views of dataSeparates logical and design views of data

Database Management System (DBMS)

Relational DBMS

• Represents data as two-dimensional tables Represents data as two-dimensional tables called relationscalled relations

• Relates data across tables based on common Relates data across tables based on common data elementdata element

• Examples: DB2, Oracle, MS SQL ServerExamples: DB2, Oracle, MS SQL Server

TYPES OF DATABASES

THE DATABASE APPROACH TO DATA MANAGEMENT

Three Basic Operations in a Relational Database

• Select:Select: Creates subset of rows that meet Creates subset of rows that meet specific criteriaspecific criteria

• Join:Join: Combines relational tables to provide Combines relational tables to provide users with informationusers with information

• Project:Project: Enables users to create new tables Enables users to create new tables containing only relevant informationcontaining only relevant information

THE DATABASE APPROACH TO DATA MANAGEMENT

Figure 7-7

Three Basic Operations in a Relational Database

THE DATABASE APPROACH TO DATA MANAGEMENT

Hierarchical and Network DBMS

Hierarchical DBMSHierarchical DBMS

• Organizes data in a tree-like structureOrganizes data in a tree-like structure

• Supports one-to-many parent-child Supports one-to-many parent-child relationshipsrelationships

• Prevalent in large legacy systemsPrevalent in large legacy systems

THE DATABASE APPROACH TO DATA MANAGEMENT

Hierarchical DBMS

Figure 7-8

THE DATABASE APPROACH TO DATA MANAGEMENT

Hierarchical and Network DBMS

Network DBMSNetwork DBMS

• Depicts data logically as many-to-many Depicts data logically as many-to-many relationshipsrelationships

THE DATABASE APPROACH TO DATA MANAGEMENT

Figure 7-9

Network DBMS

THE DATABASE APPROACH TO DATA MANAGEMENT

DisadvantagesDisadvantages

OutdatedOutdated

Less flexible compared to RDBMSLess flexible compared to RDBMS

Lack support for ad-hoc and English Lack support for ad-hoc and English language-like querieslanguage-like queries

Hierarchical and Network DBMS

THE DATABASE APPROACH TO DATA MANAGEMENT

Object-oriented DBMS:Object-oriented DBMS: Stores data and Stores data and procedures as objects that can be procedures as objects that can be retrieved and shared automatically retrieved and shared automatically

Object-relational DBMS:Object-relational DBMS: Provides Provides capabilities of both object-oriented and capabilities of both object-oriented and relational DBMSrelational DBMS

Object-Oriented databases

THE DATABASE APPROACH TO DATA MANAGEMENT

Conceptual design:Conceptual design: Abstract model of Abstract model of database from a business perspectivedatabase from a business perspective

Physical design:Physical design: shows how the database is shows how the database is actually arranged on direct access storage actually arranged on direct access storage devices.devices.

CREATING A DATABASE ENVIRONMENT

Designing Databases

THE DATABASE APPROACH TO DATA MANAGEMENT

Distributing databasesDistributing databases

Stored in more than one physical locationStored in more than one physical location

Partitioned database Partitioned database

Duplicated databaseDuplicated database

CREATING A DATABASE ENVIRONMENT

THE DATABASE APPROACH TO DATA MANAGEMENT

Multidimensional Data Analysis

On-line analytical processing (OLAP)On-line analytical processing (OLAP)

Multidimensional data analysisMultidimensional data analysis

Supports manipulation and analysis of Supports manipulation and analysis of large volumes of data from multiple large volumes of data from multiple dimensions/perspectivesdimensions/perspectives

DATABASE TRENDS

Data warehouseData warehouse

Supports reporting and query toolsSupports reporting and query tools

Stores current and historical data Stores current and historical data

Consolidates data for management Consolidates data for management analysis and decision makinganalysis and decision making

DATABASE TRENDS

Improved and easy accessibility to Improved and easy accessibility to informationinformation

Ability to model and remodel the dataAbility to model and remodel the data

Benefits of Data Warehouses

DATABASE TRENDS

Data mart

Subset of data warehouse

Contains summarized or highly focused portion of data for a specified function or group of users

DATABASE TRENDS

DataminingDatamining

Tools for analyzing large pools of data Tools for analyzing large pools of data

Find hidden patterns and infer rules to Find hidden patterns and infer rules to predict trendspredict trends

DATABASE TRENDS

Database server

Computer in a client/server environment runs a DBMS to process SQL statements and perform database management tasks

Application server

Software handling all application operations

Databases and the Web

DATABASE TRENDS

Linking Internal Databases to the Web

Figure 7-18

DATABASE TRENDS