- DBMS Tutorial
- What is Database Management System (DBMS)?
- Components of DBMS
- Applications of DBMS
- Three Schema DBMS Architecture
- Difference between DBMS and RDBMS?
- Difference between File Oriented System and DBMS
- Types of Data Models
- DBMS Schema and Instances
- Data Independence and Data Abstraction
- Database Users and Administrator
- DBMS Languages and Interfaces
DBMS ER Model
DBMS Relational Data Model
Database Users and Administrator
People who work with databases can be categorized as database users and database administrators.
Database users are the people who use the databases for their work/job and can be classified as follows:
They are unsophisticated users, i.e., users who need not be aware of the presence of the database systems or any other system supporting their usage, e.g., a user of an automatic teller machine falls in this category. Another such naïve users are end-users of a database who work through a menu oriented function program where the type and area of responses are always designated to clients.
These are computer trainers who are responsible for creating application software or client interfaces. They generally use rapid action development (RAD) tools to construct forms and reports and fourth generation language to facilitate the generation of structures and display of data screen.
They interact with the organization without writing applications. They form requests by writing queries in a database language. Engineers and other professionals generally fall into this category.
These are sophisticated users who write exclusive database implementation that does not become relevant to the traditional data processing system.
Database Administrator (DBA)
Database Administrator (DBA) is a person or group of persons responsible for overall control of the database. They are essential for developing, changing, and maintaining the three levels of DBMS. In fact, all the activities in a database 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 the information contents of a database system. DBA decides fields, types of fields, and range of values that can be stored in fields. In other words, DBA decides the schema of a database (schema is the structure of database files).
Deciding the hardware device be used
It is a database administrator’s job to determine what hardware device will be most suitable for current database applications. A tradeoff between cost and efficiency is performed by DBA to determine the storage device.
Deciding the users and data to be used by users
It is the DBA who determines clients of the database framework. DBA also decides which information contents are to be used by any particular user. This is performed by writing subschema.
Deciding the backup and recovery method
To avoid accidental loss of data, the back-up of the data is maintained at regular intervals. It is the DBA who determines which information is to be backed up and when, i.e., the amount of data and frequency of data is decided by DBA. If data is a loss, then it is the DBA how to recover data from the existing back-up.
Deciding the validation checks on the data
It is the DBA who decides which tests are to be maintained on existing data in database system standards to be maintained are also agreed by DBA.
Monitoring performance and responding to changing requirements
The DBA is essential for so organizing the framework are to get the achievements that are “best for the enterprise,” and for creating the proper adjustments as needed change.
Hence Database Administrator (DBA) is responsible for:
- Authorizing access to the database
- Coordinating and monitoring its use
- Acquiring software and hardware resources as needed
- Monitoring performance and responding to changing requirements
- Defining security and Integrity checks
- Liaising with users.
A database designer’s task is undertaken before the database is implemented.
Responsibilities of database designers are:
- Schema definition: The establishment of the original database schema.
- Storage structure and Access method definition: Writing a set of descriptions interpreted by the data storage and definition language compiler.
- Schema and Physical Organizations Modification: Writing a set of descriptions to create modifications to suitable internal framework tables (e.g., data dictionary).
Hence, Database designers are essential for:
- Identifying the record to be saved in the database
- Choosing an appropriate mechanism to describe and keep this record.
The term end-user is used to represent the user who creates the database in the development of their day to day work.
There are three types of End-users:
- Sophisticated End-Users Sophisticated end-users interact with organizations without writing functions. They structure requests by scripting queries in a database query language. This class of customer are very similar to the organization and can use the database to meet their requirements.
- Specialized End-Users Specialized end-users interact with the system by writing special database application programs.
Specialized users can write a specialized program like CAD (Computer-Aided Design), CASE (Computer-Aided Software Engineering), or Multimedia Database Programs. This specialized programmer is called specialized end-user.
- Naive UserNaïve user access data through application programs that have been written for them. They do not need to know any details of the structure of the language of the database system. They are unsophisticated users who never know writing programs or even small queries.
System Analysts decide the requirements of end-users, mainly naïve end-users, and create definitions for the canned amount that connects these requirements. This requirement includes the number of fields, size, type, constraints, etc. Once analyzing all these requirements, it also uses the skill for coding so that codes can be decided for efficient use of DBMS. After analysis, he hands it over to the database creators, who reward with the definite designing of the database.
The application programmer is necessary for scripting application software that uses the database, generally in a language such as COBOL or PL/1, to meet the customer requirement. This application software operates on the information in all the usual techniques: retrieving data, creating new data, deleting, or changing current data. They make use of DMA (Data Manipulation Language) calls, which are embedded in the programs written by them. These programs are known as application programs.
DBMS Designers and Implementers
They perform tough and responsible jobs. The DBMS framework designer knows the hardware requirements of the organizations, and through his analysis and designing ability, he produces an effective system design for the DBMS.
Tool developers use to develop software tools for DBMS. It is their job to support complete management, use, and other database development and maintenance tools for the DBMS.
Operator and Maintenance Personal
The operator, who knows how to operate the whole system, is entirely essential for proper running and operation of the hardware parts of the entire system.
The last job is the maintenance of machinery for the whole system. The maintenance not only contains repair and proper working. It also includes the up-gradation of the equipment/peripherals as and when required. All of them are technical person, and they know how to maintain, operate, and upgrade the framework.