How Much Does A Thong Weigh

Architecture ANSI / SPARC

THE 3 LEVELS OF ARCHITECTURE

The ANSI / SPARC architecture is divided into 3 levels called:

1. THE INTERNALLY is the closest to the physical storage. Is dealing with how data are physically stored. (DBA)

2. EXTERNAL LEVEL is the closest to the users, that is, which deals with how individual users perceive data. REPRESENTATIONS CAN MAKE AS MANY VIEWS AS USERS MAY HAVE A BD. (N. VISION)

3. CONCEPTUAL LEVEL is a mediation layer between the other two. (WORK DEFINING THE STRUCTURE OF STORAGE DBA).

There will be many "foreign views" different, each consisting of a representation more or less abstract of any part of the BD total. There will be only a "conceptual" formed by equally abstract representation of the database in its entirety.

There will be a single "inner sight" which represent all the database as stored physically.

the conceptual level will surely be relational, visible objects are relational tables (relational operators will be also.)

the external level will almost always be relational.

internal LEVEL not be "relational" because the things on that level are not usually only relational tables (stored), but are objects similar to those found in the internal level of other types of systems.