The Role of Databases and Database Management Systems in information management

This article differentiates between a database and a database management system.It also gives type of databases used by organisations such as centralised and distributed databases.Hirachichal,relational and the network databases are also explained.The article further explaines the uses of a database management system.A full text of this article is 1024 words 5 pages long.
In managing information, organizations are moving from file management systems to a better and efficient database management system. In this paper the author is going to differentiate between a database and a database management system [DBMS] and fully explain the types of databases used in various organizations.

A database is a collection of organized data with easy access and preserved over a long period, or a collection of interrelated data. Turban[2003:131]defines a database as a ''collection of related files, and where those related files can greatly affect user accessibility, query response times, data entry, security, and cost''. A database consolidates records previously stored in separate files so that a common pool of data records serves as a single central file or database for many data processing applications.

O''brian considers the following points as reasons for database processing. He says databases helps in eliminating data redundancy because independent data files include a lot of duplicated data. Secondly databases integrate data stored in a computer .Data can also be accessed faster from any point within the organization and users can access different portions of databases concurrently.

A database can be centralized or distributed. A centralized database has all the related files in one physical location. A decentralized database has complete copies of a database, in more than one location. There are two types of decentralized databases: replicated and partitioned-Turban [2003:132]. A replicate database has complete copies of the entire database in many locations, primarily to alleviate the single-point-of-failure problems of a centralized database as well as to increase user access responsiveness. A partitioned data base is subdivided, so that each location has a portion of the entire database.

A database management system controls all use of the databases of a computer using organization. It works in conjunction with the data management control programs of the operating system which are primarily concerned with physical input, output, and storage of data during processing.
The software program [or group of programs] as a database
management system [DBMS].The [DBMS] permits an organization to
store data in one location, from which it can be updated and
retrieved, and it provides access to the stored data by various
application programs. The DBMs also provides mechanisms for
maintaining the integrity of stored information, managing security
user access, recovering information when the system fails, and
accessing various database functions from within an application
written in a third generation, fourth generation, or object-oriented
language. The DBMS provides users with tools to add, delete,
maintain, display, print, search, and upgrade data.
Turban [2003:136] Introduction to Information Technology.
A DBMS removes the database from the control of individual programmers and computer users and places responsibility for it in the hands of the database administrator. This improves the integrity and security of the database.

There are three major types of data bases used in different organizations, namely the hierarchical structure, network structure, and the relational structure.

In the hierarchical structure, the relationship between records forms a hierarchy or tree structures. In this structure, all records are dependent and arranged in multi-level structures consisting of one root record and any number of subordinate levels. Thus, all of the relationships between records are one-to-many, since each data element is related to several records below it, but only one data element above it. The data elements or records at the highest level of the hierarchy is called the root and is the point of entry into the hierarchy. Data elements are stored and located by moving progressively downward from a root and along the branches of the tree until the desire record is located.

The advantage of a hierarchical database approach is the speed and efficiency with which it can be searched for data. This speed is possible because so much of the database is eliminated in the search with each ''turn'' going down the tree.

The second type of a database is the Network database. This type of a database views all records as sets. Each set is composed of an owner record and one or more member records. The network implements the one-to-many record structure. Unlike hierarchical data structures that require specific entrance points to find records in a hierarchy, network data structure can be entered and traversed more flexible.

The third type of a database is the relational model. It was developed in an attempt to simplify the representation of complex relationships between data elements within the database are viewed as being stored in the form of simple tables. Tables allow quick comparisons by row and column, and items are easy to retrieve by finding the point of intersection of a particular row and column.

In a relational database, these tables are called relations, and the model is based upon the mathematical theory of sets and relations. In this model, each row of data is equivalent to a record, and each column of data is equivalent to a field. In the relational model terminology, a row is called a tuple , and a column is called an attribute. The relational model is currently the most popular of the three common database structures because it provides the most flexibility and ease of use.

A database coupled with the database management system, can eliminate many of the problems associated with traditional file environment. Therefore, data redundancy, data isolation, and data inconsistency are minimized, and data can be shared among all users in the organization.

Bibliography
1 -Turban ''Introduction to information technology 2nd Ed'' 2003 John Willey & Sons
2- O''Brien ''Information Science Systems for You'' 2003
3-Barata Kimberly, ''Understanding Computers: An Overview for Records and Archives Staff'' '' IRMT 1999.
4-White, ''How Computers Work,How it Works Series'' Emeryville 1998
5-Parsons ''Computer Concepts'' Cambridge 1999

Etiwel Mutero holds a Bsc Honours Degree in Records and Archives Management through the Zimbabwe Open University.To order a full text of this article contact Etiwel on His Mobile phone +263773614293 or etiwelm02@gmail.com

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