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ANSI-SPARC - Star Trek style - v2.0
ANSI-SPARC - Star Trek style - v2.0
ANSI-SPARC - Star Trek style - v2.0
ANSI-SPARC - Star Trek style - v2.0
ANSI-SPARC - Star Trek style - v2.0
ANSI-SPARC - Star Trek style - v2.0
ANSI-SPARC - Star Trek style - v2.0
ANSI-SPARC - Star Trek style - v2.0
ANSI-SPARC - Star Trek style - v2.0
ANSI-SPARC - Star Trek style - v2.0
ANSI-SPARC - Star Trek style - v2.0
ANSI-SPARC - Star Trek style - v2.0
ANSI-SPARC - Star Trek style - v2.0
ANSI-SPARC - Star Trek style - v2.0
ANSI-SPARC - Star Trek style - v2.0
ANSI-SPARC - Star Trek style - v2.0
ANSI-SPARC - Star Trek style - v2.0
ANSI-SPARC - Star Trek style - v2.0
ANSI-SPARC - Star Trek style - v2.0
ANSI-SPARC - Star Trek style - v2.0
ANSI-SPARC - Star Trek style - v2.0
ANSI-SPARC - Star Trek style - v2.0
ANSI-SPARC - Star Trek style - v2.0
ANSI-SPARC - Star Trek style - v2.0
ANSI-SPARC - Star Trek style - v2.0
ANSI-SPARC - Star Trek style - v2.0
ANSI-SPARC - Star Trek style - v2.0
ANSI-SPARC - Star Trek style - v2.0
ANSI-SPARC - Star Trek style - v2.0
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ANSI-SPARC - Star Trek style - v2.0

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  • 1. ANSI-SPARC 3-Level Architecture
  • 2.
    • ANSI-SPAR C
    • American National Standards Institute - Standards Planning And Requirements Committee
  • 3.
    • ANSI-SPARC
    • First proposed in 1975, but never became a formal standard.
    • Most modern commercial DBMS are based on this system.
  • 4.
    • The objective of the three-level architecture is to separate the users’ view(s) of the database from the way that it is physically represented. This is desirable since:
      • It allows independent customised user views: Each user should be able to access the same data, but have a different customised view of the data. These should be independent: changes to one view should not affect others.
      • It hides the physical storage details from users: Users should not have to deal with physical database storage details. They should be allowed to work with the data itself, without concern for how it is physically stored.
      • The database administrator should be able to change the database storage structures without affecting the users’ views: From time to time rationalisations or other changes to the structure of an organisation’s data will be required.
      • The internal structure of the database should be unaffected by changes to the physical aspects of the storage: For example, a changeover to a new disk.
      • The database administrator should be able to change the conceptual or global structure of the database without affecting the users: This should be possible while still maintaining the desired individual users’ views.
  • 5. ANSI/SPARC 3-Level Architecture External Level Conceptual Level Internal Level
  • 6. ANSI/SPARC 3-Level Architecture External Level Conceptual Level Internal Level External Schema 1 External Schema n Conceptual Schema Internal Schema
  • 7. ANSI/SPARC 3-Level Architecture External Level Conceptual Level Internal Level External Schema 1 External Schema n Conceptual Schema Internal Schema Data Definition Data Manipulation Data Administration Associated Languages
  • 8. ANSI/SPARC 3-Level Architecture External Level Conceptual Level Internal Level External Schema 1 External Schema n Conceptual Schema Internal Schema Data Definition Data Manipulation Data Administration Associated Languages

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