The DBMS processes requests for data from the application program and orders the operating system to send the right data. The information systems can be computed easily while the organization’s information requirements change.
History
In the 1960's - NAVIGATIONAL DATABASE
As computers evolved, interest in a standard began to grow. Charles Bachman, author of Integrated Data Store (IDS), founded the "Database Task Group" within CODASYL. They created and standardized COBOL. In 1971 they introduced the "Codasyl approach", and soon there were some commercial products derived from it available. The Codasyl approach was integrated into a large network and used a "manual" navigation of a linked data set. However, it had no concept of "find" or "search". At that time, such an operation was too expensive to see the issue as a limitation.
In the 1970’s – RELATIONAL DATABASE
Edgar Codd was not satisfied with the Codasyl approach. Therefore, he developed the navigational model further to introduce the “search” facility which turned out to be increasingly important. In 1970, he sketched a number of papers that briefly described a new approach to database construction. It eventually successfully attained to the groundbreaking “A Relational Model of Data for Large Shared Data Banks”.
Codd described a new system to store and work with large databases. Codd's idea used a "table" of fixed-length records while Codasyl’s idea was that records were being stored in some sort of linked list of free-form records. The relational model solved the “sparse” database problems by splitting the data into a series of normalized tables, with optional elements being deleted out of the main table only if needed.
End 1970s SQL DBMS
IBM introduced a rough version in the early 1970’s where all of the data for a record did not have to be stored in a single bulk. With customer’s feedback, they were able to implement a standardized query language (SQL). As Codd’s relational model was superiorly functional, it pushes IBM to excel in the creation of System R (SQL/DS), and, later Database 2 (BD2).
In the mid-70’s, Mimer SQL was developed based on Codd's paper at Uppasala University in Switzerland. Subsequently, in the early 1980s, Mimer created the transaction handling for high robustness in applications which was then implemented on most other DBMS.
References:
http://en.wikipedia.org/wiki/Database_management_system
