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:

1. Schema definition: the creation of original database schema.

2. Storage structure and access method definition: it includes writing a set of

definitions translated by the data storage and definition language compiler.

3. 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:

1. Identifying the data to be stored in the database

2. 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.

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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