AS/A2 Computing: Database Management System (DBMS)

There are two models now used for database design (others have now been abandoned), these are:

Terms related to databases:

Separate file approach

Separate file approach diagram

Database approach

Database approach diagram

DBMS approach

DBMS approach diagram

The DBMS has a distinct structure:

DBMS layers diagram
  1. Raw data: stored as a database.
  2. Storage schema: how data is stored and accessed for a given DBMS. Here is the view of software writers such as those at Microsoft who write Microsoft Access.
  3. Logical schema: types and length of fields stored in a logical way (the entire database is available here). The logical schema answers the question "what is data and how is it stored?" This is a data dictionary and where the designer of software sets access rights for different users.
  4. Schema: The view of data for a particular user/application, see part of the database (the bits it needs).
  5. Applications: the user or applications that view, manipulate or process the data.

These notes are from a lesson on 22/06/2004.

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