Three Level Architecture of DBMS

Three Level Architecture:

The generalized architecture of a database system says ANSI/SPARC model. Many commercial systems and research database models fit within this framework. This architecture also says Three-Level Architecture of DBMS. It consists of many PCs and a workstation. These architecture depends upon how the users connects to the database. The Three-Level Architecture of DBMS diagram is given as below:

Three Level Architecture of DBMS

3-Tier Architecture of DBMS:

In DBMS, The 3-Tier architecture contains another layer between the client and server. In this architecture, the client can’t directly communicate with the server. The 3-Tier architecture uses for large web applications. It divides into the following three levels:

1. External or View level
2. Conceptual level
3. Internal or Physical level

External or View level:

The external or view level of the architecture of a Database system is the level closest to the users. This level is concerned with how the data are observed. So, most of the users of the database are not concerned with all the information.

Conceptual level:

It describes that different types of data stored in a database. This level also includes the relationships existing among data items. At this level, a database also describes logically rather than physically in terms of data structure.

However, the users of this level are not concerned with how these logical data structures will be implemented at the physical level. Rather, they are only concerned about what information would be kept in a database.

Internal level:

The lowest level of abstraction is the internal level. It is the one closest to the physical storage device. So, it is also termed as physical level. Because it describes how data are stored on the storage medium such as hard disk, magnetic tape, etc. The Internal level also defines compression and encryption techniques.