Introductory Concepts About Abstract Data Types

The subject of this course is Data Structures which concerns with ways of storing and organization of data in a computer so that it can be used efficiently. Before going deep into the subject of data structure, let us briefly describe the notion of data and information obtained from data.

1.1 Data and Information

Data is collected about an entity which can be an object or event (real or abstract) of interest to the user. An entity may be a person, place, location or thing- e.g., a salesperson, a city or a product. An entity can also be an event or unit of time such as machine break-down, a sale, or a month.

Data remains raw facts in isolation unless they are manipulated to be useful. These isolated facts do convey meaning but generally are not useful by themselves.

For example, consider a data base which stores data about a BEIT class. Data records contains students names, date of birth, address, courses, and grades on each course. If the Principal calls to find out the total number of students enrolled in BEIT class, the clerk can answer his question by looking at the data base. To the clerk, data base is information. But director of institute wants to know the total number of students in data structures class completing with A grade. The director will have to identify the students in class data base and then identify students with A grades. The information given to the principal is data to the director. It produced useful information for the director when it was processed further to output the list of only those students who have completed data structure course with A grades. This example tells that one person’s information may be another person’s data. In this sense, information eliminates uncertainty about a state, while data mean accumulated but unorganized facts.

One can say that data is to information is same as ore is to gold. A computer-based information system creates, collects and stores data, and processes that data into useful information. Symbolically,

Information = f (data, processing), a function of data and processing.

Data is, therefore, an essential ingredient for generation of information.