FILE ORGANIZATION TERMS AND CONCEPTS
THE DATA HIERARCHY

A computer system organizes data in a hierarchy that starts with bits and bytes and progresses to fields, records, files, and databases

* A bit represents the smallest unit of data a computer can handle * A group of bits, called a byte, represents a single character, which can be a letter, a number, or another symbol (A,2?,S) * A grouping of characters into a word, a group of words, or a complete number (such as a person’s name or age) is called a field
Ex: employee Last name, Customer Account number * A group of related fields, such as the student’s name, the course taken, the date, and the grade, comprises a record;
Ex: There will be one record for every one * A group of records of the same type is called a file.
Ex: Employee Benefits file, Employee payroll file * Database: A group of related files about a specific entity
Ex: HR database

PROBLEMS WITH THE TRADITIONAL FILE ENVIRONMENT
In most organizations, systems tended to grow independently without a company-wide plan. Accounting, finance, manufacturing, human resources, and sales and marketing all developed their own systems and data files. Figure 6-2 illustrates the traditional approach to information processing

* In the company as a whole, this process led to multiple master files created, maintained, and operated by separate divisions or departments. As this process goes on 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 problems are data redundancy and inconsistency, program-data dependence, inflexibility, poor 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