a) Problem with the traditional file environment
In most organizations systems tended to grow independenty without a company-wide plan. Accouning, finance, manufacturing, human resources, and sales and marketing all developed their own systems and data files. Each application of course, required its own files and its own computer program to operate. For example, the human resources functional area might have personnel master file, a payroll file, a medical insurance file, a pension file, a mailing list file, and so forth until tens, perhaps hundreds, of files and programs existed. In the company as a whole, this process led to multiple master file created, maintained, and operated by separate divisions or departments. As this process goes for 5 or 10 years, the organization is saddled with hundreds of programs and applications that are very difficult to maintain and manage. The resulting programs are data redundancy and inconsistency, program-data dependence , inflexibility, poo data security, and an inability to share data among applications. Data Redundancy and Inconsistency
Data redundancy is the presence of duplicate data in multiple data files so that the same data are stored in more than place or location. Data redundancy occurs when different groups in an organization independently collect same piece of data and store it independently of each other. Data redundancy wastes storage resources and also leads to data inconsistency, where the same attribute may have different values. Program-Data Dependence
Program-data dependence refers to the coupling of data stored in files and the specific programs required to update and maintain those files such that changes to the data . Every traditional computer program has to describe the location and nature of the data with which it works. In traditional file environment, any change in a sofware program could require a change in the data accessed by the program. One program might be modified from a five-digit to a nine-digit ZIP code. If the original data file were changed from five-digit to nine-digit ZIP codes, then other programs tha required the five-digit ZIP code would no longer work properly. Such changes could cost millions of dollars to implement properly.
Lack of Flexibility
A traditional file systems can deliver routine scheduled reports after extensive programming efforts, but it cannot deliver ad hoc reports or respond to unanticipated information requirements in a timely fashion. The information required by ad hoc requests is somewhere in the system but may be too expensive to retrieve. Several programmers might have to work for weeks to put together the required data itemd in a new file. Poor Security
Because there is little control or mangement of data, access to and dissemination of information may be out of control. Management may have no way of knowing who is accessing or even making changes to the organization’s data. Lack of Data Sharing and Availability
Because pieces of information in different files and different parts of the organization cannot be related to one another, it is virtually impossible for information to be sahred or accessed in a timely manner. Informations cannot flow freely across different functional areas or different partss of the organization. If users find different values of the same piece of information in two different systems, they may not want to use these systems because they cannot trust the accuracy of their data. b) Database management systems
A database management systems (DBMS) is software that permits an organiztion to centralize data, manage them efficiently, and provide access to the stored data by application programs. The DBMS acts as an interface between application programs and the physical data files. When the application program calls for a data item, such as gross pay, the DBMS finds this item in the database and presents it to the application program. Using traditional data files,...