User: – Users are the one who really uses the database. Users can be administrators, developers, or end-users.
Data or Database: – As we discussed already, data is one of the important factors of the database. A very huge amount of data will be stored in the database and it forms the main source for all other components to interact with each other. There are two types of data. One is user data. It contains the data which is responsible for the database, i.e.; based on the requirement, the data will be stored in the various tables of the database in the form of rows and columns. Another data is Metadata. It is known as ‘data about data’, i.e.; it stores the information like how many tables, their names, how many columns and their names, primary keys, foreign keys, etc. basically these metadata will have information about each table and their constraints in the database.
DBMS: – This is the software that helps the user to interact with the database. It allows the users to insert, delete, update, or retrieve the data. All these operations are handled by query languages like MySQL, Oracle, etc.
Database Application: – It the application program which helps the users to interact with the database by means of query languages. The database application will not have any idea about the underlying DBMS.