Data Base Management Systems(DBMS)

DBMS
A database management system(DBMS)is computer software designed for the purpose of
managing databases based on a variety of data models.A DBMS is a complex set of s/w programs that controls the organization,storage,management,& retrieval of data in a database.DBMS are categorized according to their data structures or types.It is a set of prewritten programs that are used to store,update and retrieve a Database.

As computers grew in capability,this trade-off became increasingly unnecessary and a no.of general-purpose database systems emerged;by the mid-1960s there were a no.of such systems in commercial use.The Codasyl approach was based on the manual navigation of a linked data set which was formed into a large network.


NAVIGATIONAL DBMS
Charles Bachman,founded the Database Task Group within CODASYL,In 1971they delivered their standard,which generally became known as the Codasyl approach, and soon there were a no.of commercial products based on it available.IBM also had their own DBMS system in 1968,known as IMS.IMS was a development of s/w written for the Apollo program on the System/360.IMS was generally similar in concept to Codasyl,but used a strict hierarchy for its model of data navigation instead of Codasyl's network model.



RELATIONAL DBMS
Edgar Codd worked at IBM in San Jose,California,in one of their offshoot offices that was primarily involved in the development of hard disk systems.He was unhappy with the navigational model of the Codasyl approach,notably the lack of a "search" facility which was becoming increasingly useful.In 1970,he wrote a number of papers that outlined a new approach to database construction that eventually culminated in the groundbreaking A Relational Model of Data for Large Shared Data Banks.



SQL DBMS
Codd's ideas were establishing themselves as both workable and superior to Codasyl, pushing IBM to develop a true production version of System R,known as SQL/DS,and,later,Database 2DB2.Many of the people involved with INGRES became convinced of the future commercial successof such systems, and formed their own companies to commercialize the work but with an SQL interface.Sybase,Informix, NonStop SQL and eventually Ingres itself were all being sold as offshoots to the original INGRES product in the 1980s.Even Microsoft SQL Server is actually a re-built version of Sybase,and thus,INGRES. Only Larry Ellison's Oracle started from a different chain,based on IBM's papers on System R,and beat IBM to market when the first version was released in 1978.


EXMAPLES OF DBMSs INCLUDE:

.Oracle
.DB2
.Sybase Adaptive Server Enterprise
.FileMaker
.Firebird
.Ingres
.Informix
.Microsoft Access
.Microsoft SQL Server
.Microsoft Visual FoxPro
.MySQL
.PostgreSQL
.Progress
.SQLite
.Teradata
.CSQL
.OpenLink Virtuoso
.Many others