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| 2.3 HISTORY OF DATABASE
The processing of data lead to the growth of computers as it has from the earliest days of commercial computers. According to Hollerith (1950), at the very beginning of the 20th century, punched cards were used to record US census data and mechanical systems used to process the cards and tabulate result. These cards were later used widely as means of entering data into computers. Data storage and processing techniques have evolved over the years. According to Lear (1957) magnetic tapes were developed and used to store data. With data stored on tapes, data processing tasks such as payroll were automated. The processing of data includes reading from one or more tape and writing data to a new tape. Data could also be input from punched cards and output to printers. However, tapes and cards could be read only sequentially resulting to larger data size compared to the main memory, that is why data processing programs were forced to process data in a particular order i.e. by reading and merging data from tapes and cards. According to Codd (1960) the widespread use of hard disks changed the scenario for processing since hard disks allowed direct access to data, thus data became free from being accessed sequentially. Any location on the disk could be accessed within a few milliseconds. Disks allowed the creation of network and hierarchical database giving room for data structure e.g. trees, lists to be stored so that programmers could construct and manipulate these data structures. A landmark paper by Codd (1970) defined the relational model and relational databases and procedural ways of querying data in the relational model were born. Codd later won the prestigious association of computing machinery Turing award for his work. According to Astrahan et al. (1980) initially, relational models were not used in practice because of their perceived performance disadvantage. Their performance couldn’t match those of existing network and hierarchical models. This lead to the development of a research project, system R by IBM with the aim of developing techniques for the construction of an efficient relational database system such as IBM, DB2, Oracle, ingress and DEC Rdb. According to Codd (1980), relational databases had become competitive with network and hierarchical database systems even in terms of performance, their ease of usage eventually replaced network and hierarchical databases. Programmers using such databases were forced to deal with low level implementation and programmers had to keep efficiency in mind when designing their programs which involved a lot of effort while in relational database. Almost all these low level tasks were carried out automatically by the database, allowing the programmers to work at a logical level. According to project of Saminu (2008), the 1980 also saw much research on parallel and distributed databases and work initially on object oriented databases. According to Codd (1990), the SQL language was designed to support decisions applications which are query intensive. The most important part of database 1990s was transaction processing applications which are update intensive. Many database vendors introduced parallel database products and began to add object relational support to their database. According to Bancilhon and Buneman (1990), there was an explosive growth of the W.W.B, databases were used extensively than ever before and had to support very high transaction processing rates, high reliability, 24 hours, 7 days availability and wet interface support. Download 0.97 Mb. Share with your friends:
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