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DATABASES BEFORE AND SINCE ELECTRONIC COMPUTERS
The word database was originally formed by some workers information systems to denote a collection of data shared by end - users of time sharing systems (Bob, 2005).
Before Electronic Computers
Before the invention of electronic computers, a database would probably refer to the story tellers, magicians and grandparents who were at their time the storehouses for all that was known(Selena, 1998, para. 1). This description or definition however has greatly changed ever since the appearance of electronic computers. As time went on and agriculture came about, remembering information about different storehouses of wheat, rice and maze was almost impossible for the monarchs and emperors at the time .There was simply too much information for them to remember, then the technology of writing was then invented to store all the data that needed to be stored (Selena, 1998, para. 4).
A database may be described (Kenneth & Robin, 2002) as a collection of related data that is used to store, organize and extract data. As seen above, long before the discovery of even electricity, there was already the need for storing data from our everyday activities.
After electronic computers
According to Karman et al (1989, p. 36) "the motivation for databases came from computer programmers who wanted a convenient way of handling the data used in their programs". Early computer programming languages during the 1960's such as COBOL (common business oriented language) and FORTRAN (formula translation) at the time were used to access data that companies had stored on disks, as mainframes were widely used in companies at the time. Databases nowadays are generally said to take roots from files and file systems, as the first computer applications which focused mainly on clerical tasks like order/entry processing, scheduling and more accessed data stored in computer files (Peter & Carlos, 2002, p. 9).
The file system method of storing data relates closely to the generally known technique employed mostly by offices where large file cabinets are used to hold data which usually involves carefully and most of the time manually sorting various files (data) into folders, prior to being stored in these cabinets. Thus, allowing databases nowadays to sometimes be described as an electronic file storing cabinet. However, this method of data storage is now obsolete owing to the fact that as data collection of organisations grew, and data reporting requirements became more complex, data retrieval form this system became more time consuming and yielded less useful information (Peter & Carlos, 2002, p. 10).
Database Management Systems (DBMS)
Over the years, from the 1960s up until now, databases have evolved and finally arrived at what is now known as the database management system (DBMS) which basically consists of database where data is stored in tables consisting of fields, columns and the software.
Thomas and Carolyn (2010) explained that "Database management system is a software system that enables users to define, create, maintain and control access to the database". The database management system basically is the software that interacts with the users' application and the database. Since large databases would require a way to structure and manage the large amounts of data in the database, the database management system provides facilities that allow users to easily define the database or basically create the database, perform various operations like updating, inserting, deleting and retrieving data from the database.
The data definition language (DDL) is responsible for allowing users to create or define the database i.e. allowing them to specify the data types, structures and add constraints to the data to be stored, whilst the data manipulation language (DML) is responsible for the insert, update, delete and retrieving of data (Thomas & Carolyn, 2010, p. 16). Because the data is centrally stored, it allows the data manipulation language provide a general inquiry tool which is known as a query language. The most commonly used query language is SQL which means structured query language. With SQL, data access can be controlled thereby, giving room for features like security control, integrity control, concurrency control, recovery control and data catalogs.
A data model (Greg, 2001) is described as set of concepts that can be used to describe the structure of a collection of information. Both database designers and application developers need models that would specify the exact structure of the data in a particular database, database administrators equally need models that would allow them specify the physical structure of the database so as to be able to optimize performance.
There are various data models mainly consisting of the object-based model, record-based model, physical data model and conceptual model.
The object-based model involves using concepts like entities, attributes and relationships (Thomas & Carolyn, 2010, p. 46). An entity is a distinct object in the organisation which is to be represented in the database, while an attribute is a property that describes some aspect of the object that is to be recorded (Thomas & Carolyn, 2010, p. 46). A relationship is then said to be an association between different entities. Some more types of object-based data models are the entity-relationship (ER), which has emerged in the current day as one of the major techniques for database design, semantic, functional and object-oriented model.
The record-based data model is another database model is one that consists of a number of fixed-format records possibly of different types. This data model consists
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