Behind The Scenes Databases And Information Systems 6

© 2008 Prentice-Hall, Inc. 1

Technology in ActionTechnology in Action


Technology in ActionTechnology in Action

Chapter 11Chapter 11

Behind the Scenes: Behind the Scenes: Databases and Information SystemsDatabases and Information Systems


Chapter TopicsChapter Topics

• Files and their usesFiles and their uses• Databases and their usesDatabases and their uses• Database componentsDatabase components• Types of databasesTypes of databases• Database management systemsDatabase management systems• Relational databasesRelational databases• Data warehouses and data martsData warehouses and data marts• Information systemsInformation systems• Data miningData mining


Conventional FilesConventional Files

Figure 7-3


Pros and Cons of Conventional Pros and Cons of Conventional FilesFiles

ProsPros• Easy to design because Easy to design because

of their single-application of their single-application focusfocus

• Excellent performance Excellent performance due to optimized due to optimized organization for a single organization for a single applicationapplication

ConsCons• Harder to adapt to Harder to adapt to

sharing across sharing across applicationsapplications

• Harder to adapt to Harder to adapt to new requirementsnew requirements

• Need to duplicate Need to duplicate attributes in several attributes in several files.files.


Files and TablesFiles and Tables

FileFile – the set of all occurrences of a given record structure. – the set of all occurrences of a given record structure.TableTable – the relational database equivalent of a file. – the relational database equivalent of a file.

• Types of conventional files and tablesTypes of conventional files and tables– Master filesMaster files – Records relatively permanent though values may – Records relatively permanent though values may

changechange– Transaction filesTransaction files – Records describe business events – Records describe business events– Document filesDocument files – Historical data for review without overhead of – Historical data for review without overhead of

regenerating documentregenerating document– Archival filesArchival files – Master and transaction records that have been – Master and transaction records that have been

deleteddeleted– Table lookup filesTable lookup files – Relatively static data that can be shared to – Relatively static data that can be shared to

maintain consistencymaintain consistency– Audit filesAudit files – Special records of updates to other files – Special records of updates to other files


Databases Databases

• Electronic collections of related dataElectronic collections of related data• Help us organize dataHelp us organize data• Turn data into informationTurn data into information


Advantages of Using DatabasesAdvantages of Using Databases

• Store and retrieve Store and retrieve large quantities of large quantities of informationinformation

• Enable information Enable information sharingsharing

• Provide data Provide data centralizationcentralization

• Promote data Promote data integrityintegrity

• Allow for flexible use Allow for flexible use of dataof data

Student housing

Financial AidRecording grades

Student Registration

Parents

Student Information Database


Disadvantages of Using DatabasesDisadvantages of Using Databases

• More complex than file technologyMore complex than file technology• Somewhat slower performanceSomewhat slower performance• Investment in DBMS and database Investment in DBMS and database

expertsexperts• Need to adhere to design principles to Need to adhere to design principles to

realize benefitsrealize benefits• Increased vulnerability due to Increased vulnerability due to

consolidating data in a centralized consolidating data in a centralized databasedatabase


Database TerminologyDatabase Terminology

• FieldField– Category of Category of

information information displayed in displayed in columnscolumns

– Each field has a Each field has a field namefield name

Field Name



• Data typesData types– TextText– NumericNumeric– ComputationalComputational– DateDate– MemoMemo– ObjectObject– Hyperlink Hyperlink



• RecordRecord– A group of related A group of related

fieldsfields

Record



• TableTable– A group of related recordsA group of related records

Table



• Primary keyPrimary key– A field value unique to a recordA field value unique to a record

Primary Key


Database TypesDatabase Types

• Relational databasesRelational databases– Organize data in a tableOrganize data in a table– Link tables to each other through their primary keysLink tables to each other through their primary keys

• Object-oriented databasesObject-oriented databases– Stores data in objectsStores data in objects– Handles unstructured dataHandles unstructured data

• Multidimensional databasesMultidimensional databases– Stores data in multiple dimensionsStores data in multiple dimensions– Can easily be customizedCan easily be customized– Process data much fasterProcess data much faster


Database Management Systems Database Management Systems (DBMS)(DBMS)

• Application software designed to capture Application software designed to capture and analyze dataand analyze data

• Four main operations of a DBMS are:Four main operations of a DBMS are:1.1. Creating databases and entering dataCreating databases and entering data

2.2. Viewing and sorting dataViewing and sorting data

3.3. Extracting dataExtracting data

4.4. Outputting dataOutputting data


Data ArchitectureData Architecture

Data architectureData architecture – a definition of how: – a definition of how:– Files and databases are to be developed and used to store dataFiles and databases are to be developed and used to store data

– The file and/or database technology to be usedThe file and/or database technology to be used

– The administrative structure set up to manage the data resourceThe administrative structure set up to manage the data resource

Data is stored in some combination of:Data is stored in some combination of:– Conventional filesConventional files– Operational databasesOperational databases – databases that support day-to-day – databases that support day-to-day

operations and transactions for an information system. Also operations and transactions for an information system. Also called transactional databases.called transactional databases.

– Data warehouses Data warehouses – databases that store data extracted from – databases that store data extracted from operational databases.operational databases.

• To support data miningTo support data mining– Personal databasesPersonal databases– Work group databasesWork group databases


Typical DBMS ArchitectureTypical DBMS Architecture


1. Creating Databases and 1. Creating Databases and Entering DataEntering Data

• Create field names:Create field names:– Identify each type of Identify each type of

datadata– Data dictionaryData dictionary


Sample Data Dictionary ReportSample Data Dictionary Report

Figure 7-5


Creating Databases and Creating Databases and Entering Data (cont)Entering Data (cont)

• Create individual Create individual records:records:– Key-inKey-in– Import Import


Data ValidationData Validation

• Validation Validation – Process of ensuring data Process of ensuring data

entered into the database entered into the database is correct (or at least is correct (or at least reasonable) and completereasonable) and complete

• Validation rulesValidation rules– Range checkRange check– Completeness checkCompleteness check– Consistency checkConsistency check– Alphabetic/numeric checksAlphabetic/numeric checks


2. Viewing and Sorting Data2. Viewing and Sorting Data

• Browse through Browse through recordsrecords

• Sort records by field Sort records by field namename

Before sort

After sort


3. Extracting or Querying Data3. Extracting or Querying Data

• Query Query – A question or inquiryA question or inquiry– Provides records Provides records

based on criteriabased on criteria– Structured query Structured query

language (SQL)language (SQL)

SQL


4. Outputting Data4. Outputting Data

• Reports:Reports:– PrintedPrinted– Summary data reportsSummary data reports

• Export dataExport data


Relational Database OperationsRelational Database Operations

• Relational databases Relational databases organize data into tables organize data into tables based on logical groupingsbased on logical groupings

• Relationships are links Relationships are links between tables with related between tables with related datadata

• Common fields between Common fields between tables need to existtables need to exist

• Normalization of data Normalization of data (recording data once) (recording data once) reduces data redundancyreduces data redundancy


The Relational Data ModelThe Relational Data Model

Figure 7-6


A Modern Data ArchitectureA Modern Data Architecture


AdministratorsAdministrators

Data administratorData administrator – a database specialist – a database specialist responsible for data planning, definition, responsible for data planning, definition, architecture, and management.architecture, and management.

Database administratorDatabase administrator – a specialist – a specialist responsible for database technology, database responsible for database technology, database design,construction, security, backup and design,construction, security, backup and recovery, and performance tuning.recovery, and performance tuning.– A database administrator will administer one or more A database administrator will administer one or more

databasesdatabases


From Logical Data Model …From Logical Data Model …


… … To Physical Data Model (Relational Schema)To Physical Data Model (Relational Schema)


Data StorageData Storage

• Data warehousesData warehouses– A large scale A large scale

repository of datarepository of data– Organizes all the data Organizes all the data

related to an related to an organizationorganization

– Data is organized by Data is organized by subjectsubject


• Source dataSource data– Internal Internal sourcessources

• Company databases, etc.Company databases, etc.

– External External sources sources • Suppliers, vendors, etc.Suppliers, vendors, etc.

– Customers or Web site visitors Customers or Web site visitors • Clickstream dataClickstream data

Populating Data WarehousesPopulating Data Warehouses


• Data stagingData staging

– Extract data from sourceExtract data from source

– Reformat the dataReformat the data

– Store the dataStore the data

• Software programs/procedures created Software programs/procedures created to extract the data and to reformat it for to extract the data and to reformat it for storagestorage

Data StagingData Staging


• Small slices of dataSmall slices of data

• Data of a single departmentData of a single department

Data MartsData Marts


Data WarehouseData Warehouse


Managing Data: Managing Data: Information SystemsInformation Systems

• Information systemsInformation systems– Software-based solutions used to gather and Software-based solutions used to gather and

analyze informationanalyze information

• Functions performed by information Functions performed by information systems includesystems include– Acquiring dataAcquiring data– Processing data into informationProcessing data into information– Storing dataStoring data– Providing output optionsProviding output options


Information Systems CategoriesInformation Systems Categories

• Office supportOffice support

• Transaction processingTransaction processing

• Management Management

• Decision supportDecision support


Office Support Systems (OSS)Office Support Systems (OSS)

• Assist employees in day-to-day tasksAssist employees in day-to-day tasks• Improve communicationsImprove communications• Microsoft OfficeMicrosoft Office


Transaction Processing Systems Transaction Processing Systems (TPS)(TPS)

• Keeps track of Keeps track of everyday business everyday business activitiesactivities

• Batch processingBatch processing

• Real-time Real-time processingprocessing


Management Information Systems Management Information Systems (MIS)(MIS)

• Provides timely and accurate information for Provides timely and accurate information for managers to make business decisionsmanagers to make business decisions

• Detail report:Detail report:– Transactions that Transactions that

occur during a occur during a period of timeperiod of time

• Summary report:Summary report:– Consolidate detailed Consolidate detailed

datadata• Exception report:Exception report:

– Show unusual Show unusual conditions conditions


Decision Support Systems (DSS)Decision Support Systems (DSS)

• Help managers develop solutions for Help managers develop solutions for specific problemsspecific problems


Data MiningData Mining

• Process by which data are analyzed and Process by which data are analyzed and investigatedinvestigated

• Objective is to spot patterns or trends Objective is to spot patterns or trends within the datawithin the data


Data Mining MethodsData Mining Methods

• ClassificationClassification– Define data classesDefine data classes

• EstimationEstimation– Assign a value to dataAssign a value to data

• Affinity grouping or association rulesAffinity grouping or association rules– Determine which data goes togetherDetermine which data goes together

• ClusteringClustering– Organize data into subgroupsOrganize data into subgroups

• Description and visualizationDescription and visualization– Provides a clear picture of what is happeningProvides a clear picture of what is happening


Chapter 11 Summary QuestionsChapter 11 Summary Questions

• What is a database and why is it beneficial What is a database and why is it beneficial to use databases?to use databases?



• What components make up a database?What components make up a database?



• What types of databases are there?What types of databases are there?



• What do database management systems What do database management systems do?do?



• How do relational databases organize and How do relational databases organize and manipulate data?manipulate data?



• What are data warehouses and data marts What are data warehouses and data marts and how are they used?and how are they used?



• What is an information system and what What is an information system and what types of information systems are used in types of information systems are used in business?business?



• What is data mining and how does it What is data mining and how does it work?work?

Date post:	27-Jan-2015
Category:	Technology
Upload:	guest4a9cdb
View:	104 times
Download:	0 times