ANSI-SPARC Architecture

The ANSI-SPARC Architecture, where ANSI-SPARC stands for American National Standards Institute, Standards Planning And Requirements Committee, is an abstract design standard for a Database Management System (DBMS), first proposed in 1975.

The ANSI-SPARC model however never became a formal standard. No mainstream DBMS systems are fully based on it (they tend not to exhibit full physical independence or to prevent direct user access to the conceptual level), but the idea of logical data independence is widely adopted.

The objective of the three-level architecture is to separate the user's view,

The three levels are:

The Three Level Architecture has the aim of enabling users to access the same data but with a personalised view of it. The distancing of the internal level from the external level means that users do not need to know how the data is physically stored in the database. This level separation also allows the Database Administrator (DBA) to change the database storage structures without affecting the users' views.

Some important facts about this level are:

There are three different types of schema corresponding to the three levels in the ANSI-SPARC architecture.

The overall description of a database is called the database schema.

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