Ans: Three-level architecture in DBMS is a very important and hot topic. The three-level architecture shows the working and roles of different users at different levels of the database. How database architecture is divided into levels, and what things are going through at each level.
The three-level architecture of the database system is as follows
The three-level architecture of DBMS is also called three schema architecture. There is a schema or simply called three levels present in this architecture. These levels are:
- Physical level
- Conceptual level
- View level
Physical level
This is the lowest level of the architecture that defines how data are stored in the database of the DBMS. Example: B-tree, hashing, etc.
Conceptual level
This level is present in the middle of the architecture, above the physical level and under the view level. This level defines the type of data stored and recognizes the logic used behind the relationship between two data stored in the database. This level is also called the logical level. The database admin works here.
View Level
This is the topmost layer of the architecture where users can interact with only a part of the DBMS to which they have permission instead of all DBMS. Here the concept of data abstraction is used. This level provides a view of a part of the DBMS to a particular user. So this level is called the view level. A database may have many different views.