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A database management system (DBMS) is a computer program (or more typically, a suite of them) designed to manage a database, a large set of structured data, and run operations on the data requested by numerous users. Typical examples of DBMS use include accounting, human resources and customer support systems. Originally found only in large companies with the computer hardware needed to support large data sets, DBMSs have more recently emerged as a fairly standard part of any company back office.DBMS's contrast with the more general concept of a database applications in that they are designed as the "engine" of a multi-user system. In order to fill this role, DBMSs are typically built around a private multitasking kernel with built-in networking support. A typical database application will not include these features internally, but may be able to support similar functionality by relying on the operating system to provide these features for it.
1 History
Databases have been in use since the earliest days of electronic computing, but the vast majority of these were custom programs written to access custom databases. Unlike modern systems which can be applied to widely different databases and needs, these systems were tightly linked to the database in order to gain speed at the price of flexibility.
1.1 Navigational DBMS
As computers grew in capability this tradeoff became increasingly unnecessary, as a number of general-purpose database systems emerged, and by the mid-1960s there were a number of such systems in commercial use. Interest in a standard started to grow, and Charles Bachman, author of one such product, IDS, founded the Database Task Group within Codasyl, the group responsible for the creation and standardization of COBOL. In 19711971 is a common year starting on Friday (click for link to calendar). Events January January 1 British divorce Reform Act comes into force January 2 66 die in stairway crush at Rangers v Celtic football match, Glasgow, Scotland. See Ibrox disaster. Janua they delivered their standard, which generally became known as the Codasyl approach , and soon there were a number of commercial products based on it available.
The Codasyl approach was based on the "manual" navigation of a linked dataset which was formed into a large network. When the database was first opened, the program was handed back a link to the first recordA database record is a single row of information in a relational database table. For instance, in a billiards database, one record in the score table is a single score and has fields (a. columns) for the two players, the date, who won, and the number of b in the database, which also contained pointerThis article is about the computer data type. For other meanings of pointer see pointer (disambiguation). In computer science, a pointer is a programming language datatype whose value is used to refer to ("points to") another value stored elsewhere in thes to other pieces of data. To find any particular record the programmer had to step through these pointers one at a time until the required record was returned. Simple queries like "find all the people in Sweden" required the program to walk the entire data set and collect the matching results. There was, essentially, no concept of " find " or " searchSearching is the act of trying to find something or someone. One can distinguish searching for something that is known to exist, such as an object that a poorly-organized person has stored, or that someone else has stored, or that someone has lost, or a m". This might sound like a serious limitation today, but in an era when the data was most often stored on magnetic tapeMagnetic tape is an information storage medium consisting of a magnetisable coating on a thin plastic strip. Nearly all recording tape is of this type, whether used for video with a video cassette recorder, audio storage ( reel-to-reel tape, compact audio such operations were too expensive to contemplate anyway.
IBM also had their own DBMS system in 1968, known as IMS. IMSIMS began as a hierarchical database designed by IBM for Rockwell for the Apollo program. It was used to track the bill of materials for the Saturn V. IMS is still running thirty five years later and over time has seen some interesting developments as IBM was a development of software 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.
Both concepts later became known as navigational databases due to the way data was accessed, and Bachman's 1973 Turing Award award presentation was The Programmer as Navigator. IMS is classified as a hierarchical database. IDS and IDMS (both CODASYL databases) as well as CINCOM s TOTAL database are classified as network databases.
