DATA BASE USERS: The person who use dbms in any type of way, is called dbms user.
Classification of DBMS Users: The users of a database system can be classified in the following groups, depending on their degree of expertise or the mode of their interactions with the DBMS. Database Administrator: Centralized control of the database is exerted by a person or group of persons under the supervision of a high level administrator. This person or group is referred to as the database administrator(DBA). They are the users who are most familiar with the database and are responsible for creating, modifying and maintaining its three levels.
Responsibilities of DBA:
DBA controls the database structure. The DBA administers the three levels of the database
Sets up the definition of the global view or conceptual level of the database.
Specifies the external view of the various users and applications
Responsible for the definition and implementation of the internal level, including the storage structure and access methods to be used for the
optimum performance of the DBMS.
Changes to any of the three levels are under the control of the DBA.
Mapping between the internal and the conceptual levels, as well as between the conceptual an external levels, are also defined by the DBA.
Ensuring that appropriate measures are in place to maintain the integrity of the database and that the database is not accessible to unauthorized
users is another responsibility.
Responsible for granting permission to the users of the database and stores the profile of each user in the database. This profile describes the
permissible activities of a user on that portion of the database accessible to the user via one or more user views.
Responsible for defining procedures to recover the database from failure due to human, natural or hardware causes with minimal loss of data.
Naïve Users: User who need not be aware of the presence of the database system or any other system supporting their usage are considered naïve users. The operations that can be performed by this class of users are very limited and affect a precise portion of the database. A user of an automatic teller machine(ATM) falls in this category. The user is instructed through each step of a transaction, he or she responds by pressing a coded key or entering a numeric value. Other such users are end users of the database who work through a menu-oriented application program where the type and range of response is always indicated to the user.
Online Users or Specialize users: These are users who may communicate with the database directly via an online terminal or indirectly via a user interface and application program. These users are aware of the presence of database system. A limited interaction is permitted with the database through the intermediary application program.
Sophisticated Users: They interact with the system without writing programs. Instead, they form their requests in a database query language. Each query submitted to a query processor whose function is to break down DML statement into instructions that the storage manager understands.
Application programmers: Professional programmers who are responsible for developing application programs or user-interface utilized by the naïve and online users fall into this category. The application programs could be written in a general-purpose programming language such as Assembler, C, COBOL, JAVA, PL/I and include the commands required to manipulate the database.
