In the ANSI model, DBMS architecture is divide in following levels are:
Internal level of DBMS is the one which is closest to the data storage refers to how data are actually stored on the physical medium such as hard disk, floppy disk etc. In internal level, complex low level data structure or followed the internal level of DBMS is also known as the physical level.
conceptual level deals with the data that are stored on a database and relationship among data items users involved in conceptual level is concerned with the business logical of the database.conceptual level is also known as the logical level.
External level is the one which is closest to the end user. External level deals with the way in which data are viewed by individual users. Individual users are given different views according to the users requirement. A external view insulation users from the details of the internal and conceptual levels. External level is also known as the view level.