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Chapter 5 Data

Resource Management

James A. O'Brien, and George Marakas.ManagementInformation Systems with MISource2007, 8thed. Boston, MA: McGraw-Hill, Inc.,2007. ISBN: 13 9780073323091

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Chapter 5 Data Resource ManagementChapter 5 2

Logical Data Elements

data may be logically organized into characters, fields, records,files, and databases

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Logical Data Elements Character

A single alphabetic, numeric, or other symbol Field or data item

Represents an attribute (characteristic or quality)of some entity (object, person, place, event) Example: salary, job title

Record Grouping of all the fields used to describe the attributes of an

entity Example: payroll record with name, SSN, pay rate

File or tableA group of related records

DatabaseAn integrated collection of logically related

data elements

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Electric Utility Database

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Database Structures

Common database structuresHierarchicalNetworkRelationalObject-orientedMulti-dimensional

Database management system (DBMS) packages aredesigned to use a specific data structure to provide endusers with quick, easy access to information stored indatabases.

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Hierarchical Structure

Early DBMS structure

Records arranged in tree-like structure

Relationships are one-to-many

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Network Structure

Used in some mainframe DBMS packagesMany-to-many relationships

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Relational Structure

Most widely used structure

Data elements are stored in tablesRow represents a record; column is a field Can relate data in one file with data in another,

if both files share a common data element

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Relational Operations

SelectCreate a subset of records that meet a stated

criterionExample: employees earning more than

$30,000 Join

Combine two or more tables temporarilyLooks like one big table

ProjectCreate a subset of columns in a table

Three basic operations can be performed on a relational database to

create useful sets of data.

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Multidimensional Structure Variation of relational modelUses multidimensional structures to

organize data and express the relationshipsbetween data

Data elements are viewed as being in cubes You can visualize multidimensional structures as cubes

of data and cubes within cubes of data. Each side of thecube is considered a dimension of the data

Popular for analytical databases that supportOnline Analytical Processing (OLAP) in whichfast answers to complex business queries areexpected.

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Multidimensional Model

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Object-Oriented Structure

Anobjectconsists ofData values describing the attributes of an

entity

Operations that can be performed on the data This encapsulation capability allows the object-

oriented model to handle complex types of data(graphics, pictures, voice, and text) more easily

than other database structures. InheritanceNew objects can be created by replicating

some or all of the characteristics of parent

objects

is considered one of the key technologies of a new generation of

multimedia Web-based applications.

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Source: Adapted from Ivar Jacobsen, Maria Ericsson, and Ageneta Jacobsen, The ObjectAdvantage: Business Process Reengineering with Object Technology(New York: ACM Press,1995), p. 65.Copyright @ 1995, Association for Computing Machinery. By permission.

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Used in object-oriented database managementsystems (OODBMS)

Supports complex data types more efficiently

than relational databasesExample: graphic images, video clips,

web pages Examples include multimedia object extensions to IBMs

DB2 and Oracles object-based cartridges for Oracle10g.

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Evaluation of Database Structures HierarchicalWorks for structured, routine transactionsCant handle many-to-many relationship

NetworkMore flexible than hierarchicalUnable to handle ad hoc requests

Relational

Easily responds to ad hoc requestsEasier to work with and maintainNot as efficient/quick as hierarchical or network

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The major limitation of the relational model is thatrelational database management systems cannotprocess large amounts of business transactions asquickly and efficiently as those based on the hierarchical

and network models


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Database Development

Database Administrator (DBA) In charge of enterprise database development Improves the integrity and security of

organizational databasesUses Data Definition Language (DDL) to

develop and specify data contents,relationships, and structure

Stores these specifications in a datadictionary or a metadata repository

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Data Dictionary

A data dictionaryContains data about data (metadata)Relies on specialized software component to

manage a database of data definitions It contains information on..The names and descriptions of all types of

data records and their interrelationships

Requirements for end users access and useof application programs

Database maintenanceSecurity

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Database Development

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Data Planning Process

Database development is a top-down processDevelop an enterprise model that defines the

basic business process of the enterprise

Define the information needs of end users ina business process Identify the key data elements that are

needed to perform specific business activities

(entity relationship diagrams)

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Entity Relationship Diagram

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Database Design Process

Data relationships are represented in a data model thatsupports a business process This model is the schemaor subschemaon which to

base The physical design of the database The development of application programs to support

business processes Logical Design

Schema - overall logical view of relationships

Subschema - logical view for specific end usersData models for DBMS

Physical Design How data are to be physically stored and

accessed on storage devices

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Logical and Physical Database Views

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Data Resource Management

Data resource management is a managerial activityUses data management, data warehousing,

and other IS technologiesManages data resources to meet the information

needs of business stakeholders Data stewards

Dedicated to establishing and maintaining thequality of data

Need business, technology, and diplomatic skillsFocus on data content

Judgment is a big part of the job

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Types of Databases

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Operational Databases

Stores detailed data needed to support businessprocesses and operationsAlso called subject area databases(SADB),

transaction databases, and productiondatabasesDatabase examples: customer, human

resource, inventory

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Distributed Databases Distributed databases are copies or parts of databases stored on

servers at multiple locations Improves database performance at worksites

Advantages Protection of valuable data Data can be distributed into smaller databases

Each location has control of its local data All locations can access any data, any where

Disadvantages Maintaining data accuracy

Replication Look at each distributed database and find changes

Apply changes to each distributed database Very complex

Duplication One database is master Duplicate the master after hours, in all locations

Easier to accomplish

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External Databases

Databases available for a fee from commercialonline services, or free from the WebExample: hypermedia databases, statistical

databases, bibliographic and full textdatabasesSearch engines like Google or Yahoo are

external databases

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Hypermedia Databases

A hypermedia database containsHyperlinked pages of multimedia Interrelated hypermedia page elements,

rather than interrelated data records

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Components of Web-Based

System

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Data Warehouses

Stores static data that has been extracted fromother databases in an organizationCentral source of data that has been cleaned,

transformed, and catalogedData is used for data mining, analytical

processing, analysis, research, decision support Data warehouses may be divided into data martsSubsets of data that focus on specific aspects

of a company (department or business process)

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Data Warehouse Components

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Applications and Data Marts

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Data Mining

Data in data warehouses are analyzed to revealhidden patterns and trendsMarket-basket analysis to identify new

product bundlesFind root cause of qualify or manufacturing

problemsPrevent customer attrition

Acquire new customersCross-sell to existing customersProfile customers with more accuracy

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Traditional File Processing

Data are organized, stored, and processed inindependent filesEach business application designed to use

specialized data files containing specifictypes of data records

ProblemsData redundancy

Lack of data integrationData dependence (files, storage devices,software)

Lack of data integrity or standardization

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Traditional File Processing

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Database Management

Approach The foundation of modern methods of managing

organizational dataConsolidates data records formerly in

separate files into databasesData can be accessed by many different

application programs

A database management system (DBMS) isthe software interface between users anddatabases

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Database Management

Approach

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Database Management System

In mainframe and server computer systems, asoftware package that is used toCreatenew databases and database

applicationsMaintainthe quality of the data in an

organizations databasesUsethe databases of an organization to

provide the information needed by end users

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Common DBMS Software

Components Database definitionLanguage and graphical tools to define

entities, relationships, integrity constraints,and authorization rights

Nonprocedural accessLanguage and graphical tools to access data

without complicated coding Application developmentGraphical tools to develop menus, data entry

forms, and reports

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Common DBMS Software

Components Procedural language interfaceLanguage that combines nonprocedural access

with full capabilities of a programming language Transaction processingControl mechanism prevents interference from

simultaneous users and recovers lost data after

a failure

Database tuningTools to monitor, improve database performance

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Database Management System

Database DevelopmentDefining and organizing the content,

relationships, and structure of the data neededto build a database

Database Application DevelopmentUsing DBMS to create prototypes of queries,

forms, reports, Web pages

Database MaintenanceUsing transaction processing systems and

other tools to add, delete, update, and correctdata

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DBMS Major Functions

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Database Interrogation

End users use a DBMS query feature or reportgenerator

Response is video display or printed report

No programming is required Query language

Immediate response to ad hoc data requests

Report generatorQuickly specify a format for information you

want to present as a report

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SQL QueriesStructured, international standard query

language found in many DBMS packages

Query form is SELECTFROMWHERE

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Boolean LogicDeveloped by George Boole in the mid-1800sUsed to refine searches to specific

informationHas three logical operators: AND, OR, NOT

ExampleCats OR felines AND NOT dogs OR

Broadway

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Graphical and Natural Queries It is difficult to correctly phrase SQL and other

database language search queries

Most DBMS packages offer easier-to-use,point-and-click methodsTranslates queries into SQL commandsNatural language query statements are similar

to conversational English

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Graphical Query Wizard

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Database Maintenance

Accomplished by transaction processingsystems and other applications, with the supportof the DBMS

Done to reflect new business transactions andother eventsUpdating and correcting data, such as

customer addresses

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Application Development

Use DBMS software development tools todevelop custom application programsNot necessary to develop detailed data-

handling procedures using conventionalprogramming languagesCan include data manipulation language

(DML) statements that call on the DBMS to

perform necessary data handling

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Documents