Degree/s-qualityData- raw factsAbstract- concept    “Data designer produced a quality data model”
   American National Standard Institute    (ANSI) Standards Planning and Requirements    Committee (SPARC)Defined a frame...
Defines three levels of abstraction:   external   conceptual   internal
   Is the end user’s view of the data    environment.   The term end user’s refers to the people who    use the applicat...
   A specific representation of an external view is    known as an external schema.   Each     external   schema       i...
   It makes it easy to identify specific data    required to support each business unit’s    operations.
   It makes the designer’s job easy by providing    feedback about the model’s adequacy.
   It helps to ensure security constraints in the    database    design.   Damaging     an    entire    database is more ...
   It makes application program development    much simpler.
   The conceptual model represents as a global    view of the entire database as viewed by the    entire organization.
   Conceptual model integrates all external    views (entities, relationships, constraints, and    processes) into single...
   First, it provides a relatively easily bird’s eye    (macro level) view of the data environment.
   Second, the conceptual model is independent    of both software and hardware.
1.   Software independence means that the model     does not depend on the DBMS software used     to implement the model.2...
   Generally, the term logical design is used to    refer to the task of creating a conceptual data    model that could b...
   Once a specific DBMS has been selected, the    internal model maps the conceptual model to    the DBMS.
   The internal model is the representation of    the database as seen by the DBMS.
   In other words, the internal model requires    the designer to match the conceptual model’s    characteristics and con...
   Internal model depends on specific database    software, it is said to be the software    dependent.
   Internal model is still hardware-independent    because it is unaffected by the choice of the    computer on which the...
   This lowest level of data abstraction is    concerned exclusively with physical storage    methods.
   Early data models forced the database    designer to take the details of the physical    model’s data storage requirem...
   However, the now dominant relational model    is aimed largely at the logical rather than the    physical level; there...
Thanks!Prepared by Me    Yours truly,
Degrees of data abstraction   copy
Degrees of data abstraction   copy
Degrees of data abstraction   copy
Degrees of data abstraction   copy
Degrees of data abstraction   copy
Degrees of data abstraction   copy
Degrees of data abstraction   copy
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Degrees of data abstraction copy

  1. 1. Degree/s-qualityData- raw factsAbstract- concept “Data designer produced a quality data model”
  2. 2.  American National Standard Institute (ANSI) Standards Planning and Requirements Committee (SPARC)Defined a framework for data modelling based on degrees of data abstraction.
  3. 3. Defines three levels of abstraction: external conceptual internal
  4. 4.  Is the end user’s view of the data environment. The term end user’s refers to the people who use the application programs to manipulate the data and generate information.
  5. 5.  A specific representation of an external view is known as an external schema. Each external schema includes the appropriateness entities, relationships, processes, and constraints imposed by the business unit.
  6. 6.  It makes it easy to identify specific data required to support each business unit’s operations.
  7. 7.  It makes the designer’s job easy by providing feedback about the model’s adequacy.
  8. 8.  It helps to ensure security constraints in the database design. Damaging an entire database is more difficult when each business unit works with only a subset of data.
  9. 9.  It makes application program development much simpler.
  10. 10.  The conceptual model represents as a global view of the entire database as viewed by the entire organization.
  11. 11.  Conceptual model integrates all external views (entities, relationships, constraints, and processes) into single global of a data. Also known as conceptual schema
  12. 12.  First, it provides a relatively easily bird’s eye (macro level) view of the data environment.
  13. 13.  Second, the conceptual model is independent of both software and hardware.
  14. 14. 1. Software independence means that the model does not depend on the DBMS software used to implement the model.2. Hardware independence means that the model does not depend on the hardware used in the implementation of the model.
  15. 15.  Generally, the term logical design is used to refer to the task of creating a conceptual data model that could be implemented in any DBMS.
  16. 16.  Once a specific DBMS has been selected, the internal model maps the conceptual model to the DBMS.
  17. 17.  The internal model is the representation of the database as seen by the DBMS.
  18. 18.  In other words, the internal model requires the designer to match the conceptual model’s characteristics and constraints to those of the selected implementation model.
  19. 19.  Internal model depends on specific database software, it is said to be the software dependent.
  20. 20.  Internal model is still hardware-independent because it is unaffected by the choice of the computer on which the software is installed.
  21. 21.  This lowest level of data abstraction is concerned exclusively with physical storage methods.
  22. 22.  Early data models forced the database designer to take the details of the physical model’s data storage requirements into account.
  23. 23.  However, the now dominant relational model is aimed largely at the logical rather than the physical level; therefore it does not require the physical-level details common to its predecessors.
  24. 24. Thanks!Prepared by Me  Yours truly,

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