Data Base Concepts

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Data Base Concepts
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Origin of DB Concept

• Data base concept of military system origin
• Probable source is SDC circa 1960 a RAND
  corporation spin-off doing USAF systems
• SDC made deliberate attempts to promote systems
  approach for corporate management
• Crucial Characteristics
• Constantly updated
• Accessed interactively (real-time)
• Shared between users/systems, gives different
  views to each

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DB in Corporate World

• Data base concept crosses over to corporate use
  in early 1960s
• Total Systems Concept
• (aka Management Information System)
• Integrated command system for management real
  time, on-line
• Data base gains scattered usage as crucial,
  shared bucket of facts for this system
• Discussion of DB predates discussion of DBMS by
  about seven years.

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File Management Software

• As old as corporate computing
• First documented in GE, mid-1950s
• Generalized set of subroutines to update, query,
  maintain sequential files
• Applications keep separate files
• But coding, altering, sharing become easier
• By mid-1960s, becoming more sophisticated
• Offered as commercial products
• Working with new random-access devices
• Often called Information Management software
  (GIS, IMS etc)

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A File Based System, 1962
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State of Play circa 1967

• Data base concept is
• Fashionable
• Widely promoted as key to MIS
• Vaporware, revolutionary
• Real-time, on-line, total system
• Closely tied to information retrieval
• File management software is
• Growth area
• Slowly evolving
• Practical, batch-oriented, evolutionary

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The Information Pyramid

• Information turns control of low-level
  administration into a claim to strategic
  centrality in a new vision of management
• Bottom level of the pyramid is the data base

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Data Base Management System

• New concept Data Base Management System
• At last! File Management System meets Data Base.
• Appears circa 1968
• CODASYL Data Base Task Group
• Originally in context of extensions to COBOL
• Based on consideration of current file management
  products, directions for future.

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ANSI-SPARC Three-level Architecture
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DBMS Foundational Concept

• DBMS as software layer between data, users
• Different interfaces, languages for
• Programs programmers
• Ad-hoc managerial reporting
• Data definition
• maintenance and administration
• Sets up links between files
• BUT rigid, standardized format remain

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Components of a DBMS
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Implications

• DBMS concept
• Shapes evolution of modern computing
• Underlies interest in information/data as
  strategic resource from mid-70s onward
• Aids in corporate information system development,
  maintenance
• But at a price
• New concept of database is narrower
• More general information retrieval problems are
  excluded

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DBMS For Corporate Applications

• Advantages
• easier reporting,program independence from
  details of data,
• faster application development,
• easier maintenance
• Aids integration of different applications
• Disjoint with organizational hopes for data base
  as savior of MIS concept!
• Still unable to deliver on initial dream
• More for programmers than managers

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Not One Big Database

• Big central database doesnt work
• Finish up with dozens/hundreds of little data
  bases
• Physically separate
• All incomplete
• Different data formats
• Different concepts of data
• Dominant model is relational (eg Oracle)
• Good for updating
• Flexible
• Can be slow complex to extract data for reports

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From Recent DB Textbook
Management Hierarchy
External data sources and
Top
summarized, tactical databases
(strategic)
Summarized, integrated
Middle
operational databases
(tactical)
Lower
Individual operational
(operational)
databases
Operational databases
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Data Warehouse Concept

• Emerges early 1990s
• One big DB for everything has failed, so
• Leave transactional systems spread out
  (physically, organizationally), BUT
• Make a second, read-only copy of everything in a
  centralized data warehouse. Update regularly.
• Lots of work for consultants
• Copying, cleaning, reformatting data
• Restructuring data around business areas and for
  easy querying
• Providing query tools for managerial users

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Data Warehouse Information Flows