Data Base ConceptsData Base Concepts

Origin of DB ConceptOrigin of DB Concept

Data base concept of military system originData base concept of military system origin– Probable source is SDC circa 1960 – a RAND Probable source is SDC circa 1960 – a RAND

corporation spin-off doing USAF systemscorporation spin-off doing USAF systems– SDC made deliberate attempts to promote “systems SDC made deliberate attempts to promote “systems

approach” for corporate managementapproach” for corporate management

Crucial CharacteristicsCrucial Characteristics– Constantly updatedConstantly updated– Accessed interactively (“real-time”)Accessed interactively (“real-time”)– Shared between users/systems, gives different views Shared between users/systems, gives different views

to eachto each

DB in Corporate WorldDB in Corporate World

““Data base” concept crosses over to Data base” concept crosses over to corporate use in early 1960scorporate use in early 1960s““Total Systems Concept”Total Systems Concept”– (aka Management Information System)(aka Management Information System)– Integrated command system for management Integrated command system for management

– real time, on-line– real time, on-line– Data base gains scattered usage as crucial, Data base gains scattered usage as crucial,

shared “bucket of facts” for this systemshared “bucket of facts” for this system

Discussion of DB predates discussion of Discussion of DB predates discussion of DBMS by about seven years.DBMS by about seven years.

File Management SoftwareFile Management Software

As old as corporate computingAs old as corporate computing– First documented in GE, mid-1950sFirst documented in GE, mid-1950s– Generalized set of subroutines to update, query, Generalized set of subroutines to update, query,

maintain sequential filesmaintain sequential files

Applications keep separate filesApplications keep separate files– But coding, altering, sharing become easierBut coding, altering, sharing become easier

By mid-1960s, becoming more sophisticatedBy mid-1960s, becoming more sophisticated– Offered as commercial productsOffered as commercial products– Working with new random-access devicesWorking with new random-access devices

Often called “Information Management” software Often called “Information Management” software (GIS, IMS etc)(GIS, IMS etc)

A File Based System, 1962A File Based System, 1962

State of Play circa 1967State of Play circa 1967Data base concept isData base concept is– FashionableFashionable– Widely promoted as key to MISWidely promoted as key to MIS– Vaporware, revolutionaryVaporware, revolutionary– Real-time, on-line, “total system”Real-time, on-line, “total system”– Closely tied to information retrievalClosely tied to information retrieval

File management software isFile management software is– Growth areaGrowth area– Slowly evolvingSlowly evolving– Practical, batch-oriented, evolutionaryPractical, batch-oriented, evolutionary

The Information PyramidThe Information Pyramid

““Information” turns Information” turns control of low-level control of low-level administration into a administration into a claim to strategic claim to strategic centrality in a new centrality in a new vision of vision of managementmanagement

Bottom level of the Bottom level of the pyramid is the pyramid is the “data “data base”base”

Data Base Management SystemData Base Management System

New concept “Data Base Management New concept “Data Base Management System”System”– At last! File Management System meets Data At last! File Management System meets Data

Base.Base.

Appears circa 1968Appears circa 1968– CODASYL Data Base Task GroupCODASYL Data Base Task Group– Originally in context of extensions to COBOLOriginally in context of extensions to COBOL– Based on consideration of current file Based on consideration of current file

management products, directions for future.management products, directions for future.

ANSI-SPARC Three-level ANSI-SPARC Three-level ArchitectureArchitecture

DBMS – Foundational ConceptDBMS – Foundational ConceptDBMS as software layer between data, DBMS as software layer between data, usersusers– Different interfaces, languages forDifferent interfaces, languages for

Programs & programmersPrograms & programmers

Ad-hoc managerial reportingAd-hoc managerial reporting

Data definitionData definition

maintenance and administrationmaintenance and administration

Sets up links between filesSets up links between files– BUT rigid, standardized format remainBUT rigid, standardized format remain

Components of a DBMSComponents of a DBMS

ImplicationsImplications

DBMS conceptDBMS concept– Shapes evolution of modern computingShapes evolution of modern computing– Underlies interest in “information/data as Underlies interest in “information/data as

strategic resource” from mid-70s onwardstrategic resource” from mid-70s onward– Aids in corporate information system Aids in corporate information system

development, maintenancedevelopment, maintenance

But at a priceBut at a price– New concept of database is narrowerNew concept of database is narrower– More general information retrieval problems More general information retrieval problems

are excludedare excluded

DBMS For Corporate ApplicationsDBMS For Corporate Applications

Advantages:Advantages:– easier reporting,easier reporting,

program independence from details of data,program independence from details of data,– faster application development,faster application development,– easier maintenanceeasier maintenance– Aids integration of different applicationsAids integration of different applications

Disjoint with organizational hopes for data Disjoint with organizational hopes for data base as savior of MIS concept!base as savior of MIS concept!– Still unable to deliver on initial dreamStill unable to deliver on initial dream– More for programmers than managersMore for programmers than managers

Not One Big DatabaseNot One Big Database

Big central database doesn’t workBig central database doesn’t workFinish up with dozens/hundreds of little data Finish up with dozens/hundreds of little data basesbases– Physically separatePhysically separate– All incompleteAll incomplete– Different data formatsDifferent data formats– Different concepts of dataDifferent concepts of data

Dominant model is “relational” (eg Oracle)Dominant model is “relational” (eg Oracle)– Good for updatingGood for updating– FlexibleFlexible– Can be slow & complex to extract data for reportsCan be slow & complex to extract data for reports

From Recent DB TextbookFrom Recent DB Textbook

Top(strategic)

Middle(tactical)

Lower(operational)

Individual operationaldatabases

Summarized, integratedoperational databases

External data sources andsummarized, tactical databases

Operational databases

Management Hierarchy

Data Warehouse ConceptData Warehouse Concept

Emerges early 1990sEmerges early 1990s

One big DB for everything has failed, soOne big DB for everything has failed, so– Leave “transactional” systems spread out (physically, Leave “transactional” systems spread out (physically,

organizationally), BUTorganizationally), BUT– Make a second, read-only copy of everything in a Make a second, read-only copy of everything in a

centralized “data warehouse”. Update regularly.centralized “data warehouse”. Update regularly.

Lots of work for consultantsLots of work for consultants– Copying, “cleaning”, reformatting dataCopying, “cleaning”, reformatting data– Restructuring data around business areas and for Restructuring data around business areas and for

easy queryingeasy querying– Providing query tools for managerial usersProviding query tools for managerial users

Data Warehouse Information Data Warehouse Information FlowsFlows