DATABASE ENVIRONMENT

ANTI SPARC ARCHITECTURE

-ANSI-SPARC stands for American National Standards Institute, Standards Planning And Requirements Committee.

-It is an abstract design standard for a Database Management System (DBMS), first proposed in 1975.

-Most modern commercial DBMS are based on this architecture.

•External Level

–Users’ view of the database.

–Describes that part of database that is relevant to a particular user.

•Conceptual Level

–Community view of the database.

–Describe what data is stored within the whole database and how the data is inter-related. The

conceptual level does not specify how the data is physically stored.

–DBA relevant. Hardware & software independent.

•Internal Level (incl. Physical storage)

–Physical representation of the database on the computer.

–Describes how the data is actually stored (e.g., data type, index) in the database and the hardware.

Objectives

-It allows independent customized user views.

-It hides the physical storage details from users.

-The database administrator should be able to change the database storage structures without affecting the users’ views.

STEPS TOWARDS DATABASE DEVELOPMENT

•Construct Conceptual Model

•Construct Logical Model

•Implement Physically