DBMS USERS

TOPICS TO BE DISCUSSED…………… Actors on the scene: Persons whose job involves use of a large database are: (a) Database administrator (b) Database designers (c) End Users (d) System Analyst Workers behind the scene Persons whose job involves design, development, operation and maintenance of DBMS software are: (a) DBMS designers and implementers (b) Tool Developers (c) Operator and maintenance personal

Database Administrator (DBA) Database Administrator is a person or group of persons responsible for overall control of database system. All the activities of database system are controlled by DBA. Some of the main activities are as follows: Deciding the information contents of database system: It is the DBA who decides information contents of database system.DBA decides fields, type of fields and range of values that can be stored in fields. In other words DBA decides schema of database

Deciding hardware device to be used: It is the database administrator’s job to decide which hardware device will be most suitable for current database applications. Trade off between cost and efficiency is perfromed by DBA to decide the storage device. Deciding the users and data to be used by users: It is the DBA who decides users of the database system.DBA also decides which information contents are to be used by a particular user. This is performed by writing subschema.

Deciding the back-up and recovery method: to avoid accidental loss of data back-up of data is maintained on regular intervals. It is the DBA who decides which data is to be backed up and when i.e. amount of data and frequency of data decided by DBA. If data is loosed then it is the DBA who recover data from existing back-up. Deciding the validation checks on the data: It is the DBA who decides which checks are to be maintained on existing data in database system. Standards to be maintained are also decided by DBA.

Monitoring performance and responding to changing requirements: The DBA is responsible for organizing the systems to get the performance that is best for the enterprise and for making the appropriate adjustment and requirements change.

Database Designers Database designers task is undertaken before the database is actually implemented. Responsibilities of Database designers are: Schema definition: the creation of original database schema. Storage structure and access method definition: it includes writing a set of definitions translated by the data storage and definition language compiler. Schema and physical organization Modifications: it includeswriting a set of definitions to generate modifications to appropriate internal system tables

Hence, database Designers are responsible for: Identifying the data to be stored in the database Choosing appropriate structure to represent and store this data.

 End Users End users are the users, who use the applications developed. End users need not know about the working, database design, the access mechanism etc. They just use the system to get their task done. End users are of two types: a) Direct users      b) Indirect users

a) Direct users: Direct users are the users who see the computer, database system directly, by following instructions provided in the user interface. They interact using the application programs already developed, for getting the desired result. E.g. People at railway reservation counters, who directly interact with database. b) Indirect users: Indirect users are those users, who desire benefit form the work of DBMS indirectly. They use the outputs generated by the programs, for decision making or any other purpose. They are just concerned with the output and are not bothered about the programming part.

System Analyst System analysts determine the requirements of end users. He also analyses the user requirement so that the DBMS data fields can be selected to fulfill user needs. This requirements include the number of fields, size, type etc. Once analyzing all these requirement he also uses the skill for coding so that codes can be decided for efficient use of DBMS.

Application Programmers These users write application programs to interact with the database. Application programs can be written in some programming language such a COBOL, PL/I, C++, JAVA or some higher level fourth generation language. Such programs access the database by issuing the appropriate request, typically a SQL statement to DBMS.

Functions of Application Programmer Determine the requirements of end users, especially naive and parametric end users, and develop specifications for canned transactions that meet these requirements Application programmers implement these specifications as programs; then they test, debug, document, and maintain these canned transactions

DBMS Designers And Implementers They perform tough and responsible job. The DBMS system designer knows the hardware requirements of the system and through his analyzing and designing capability, he produces an efficient system design for the DBMS. The DBMS system implementers are those who help for hardware implementation of the entire system. They do not play role in software implementation.

Operators and Maintenance Personal Tool Developers Tool developers help to develop the software tools for the DBMS. It is their job to provide complete management, help and other database creation and maintenance tools for the DBMS. Operators and Maintenance Personal The operators, who know to operate the entire system, are fully responsible for proper running and operation of hardware parts of complete system. The final job is the maintenance of machinery for the entire system. The maintenance not only includes repair and proper working, it also includes the up gradation of equipments as an when required. All of them are technical people and they know how to maintain, operate and upgrade the system.

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