Explain the architecture of DBMS or three schema architecture?

                In this architecture schema can we define at the following three level-----

                   1. Internal level
                   2. Conceptual level
                   3. External level or view level

 1. Internal level: 
                                 The internal view is at the lowest level of the database abstraction. It is the one closest to the physical storage, i.e, in this level, the data is actually Store. The internal level has an internal schema use a physical data model and describe the complete details of data storage and access path for the database. It indicates how the data will be store and describe the data structure that could be used by the database.

 2.  Conceptual level: 
                                      The conceptual level have a conceptual schema, which describe the structure of the hole database for a community of user. The conceptual schema hides the details of the physical storage structure and consented on describing entities, data type, relationship, user operation and constants. A high level data model or implementation data model can be used at this level.

 3.  External level or View level: 
                                                            The external or user view is at the highest level of the database abstraction. It is a view level and includes a number of the user's views. Each external schema describe the part of the database, that a particular user group is interested in and hides the rest of the database from the user group.

       By following figure we can demonstrate at the basic concept of the three schema architecture or architecture of DBMS--------- 

 
Fig: Three schema architecture or architecture of DBMS