History of DBMS or Different People Behind DBMS:-

 As the use of computers in maintaining data increased in late 1960’s the DBTG (Database Task Group) of CODASYL (Conference on Data System Languages) was set up to propose DBMS standards.

 Charles Bachman who was working for the development of the first commercial DBMS IDS (Integrated Data Store) data model (1964 onwards) introduced the earliest diagrammatic techniques for representing relationships database called data structure diagrams.

 The database standards specifications were published by the CODASYL committee, which was referred to as CODASYL DBTG 1971 report. This report contains scheme and subscheme DDL and DML for use with COBOL. A revised report (CODASYL1971) was made in 1978 and other revision was made in 1881.

 A relational model was proposed by E.F.Codd in 1970 in a paper. Relational algebra and theoretical foundations for the relational model were discussed by Codd in his subsequent papers published in 1971, 1972 and 1974. The first hierarchical DBMS-IMS (Information Management System) was developed by IBM in late 1960’s.

 However, there are very few documents available regarding theoretical emergence of hierarchical model. The most popular SQL (Structured Query Language) was described by Boyce etal in 1975. A lot of work has been done to produce the DBMS now in use. Some of the contributors are – Chamberlin, Date etc. ANSI outlined original SQL standard in 1986 which was revised in 1992. 

Users of DBMS:-

 1. DBA (Database Administrator): A database administrator (short form DBA) is a person responsible for the installation, configuration, upgrade, administration, monitoring and maintenance of physical databases.

 The role includes the development and design of database strategies, monitoring and improving database performance and capacity, and planning for future expansion requirements. They may also plan, co-ordinate and implement security measures to safeguard the database.

Role of DBA: 

The person who has control over both programs and data of the system is called Database Administrator (DBA). The functions of DBA include the following: 

i) Schema definition:

The DBA creates the original database schema by writing a set of definitions that is translated by the DDL compiler in a set of tables that are stored permanently in the data dictionary.

 ii) Storage structure and access method definition:

DBA creates appropriate storage structures and access methods by writing a set of definitions which is translated by data storage and data definition language compiler. 

iii) Schema and physical-organisation modification:

 Programmers accomplish the modifications either to schema or physical storage organisation by writing a set of definitions used by DDL or data storage compiler to generate modifications to appropriate internal system.

 iv)Granting data access authorisation: 

The granting of different types of authorisation allows the DBA to regulate which parts of the database various users can access. 

v) Integrity constraint specifications: The data values stored in the database must satisfy certain types of consistency constraints. Example: Account balance cannot fall below Rs.1000/- in case transaction is done by cheque. Such a constraint must be defined explicitly by the DBA. 

2. Database Designers:

 Database designer are responsible for designing the database objects. The database objects like tables, columns, their data types, forms and reports must be properly designed as per the requirement so that those can be flexibly used by the users. The database designers have to frequently communicate with all the prospective database users, understand and study their requirements. They develop the view of database that supports the requirements. Once the database design is complete they assist DBA.

3. Application Programmers: 

Those people who write the codes of the programs according to the designs suggested by the database designers are called application programmers. They also test, debug, document and maintain these programs.

 4. End Users:

Those people who access the database for different purposes are called end users. They are categorised as follows:

 i) Casual end users.

ii) Naive or Parametric end users.

 iii) Sophisticated end users .

iv) Stand alone users.