Introduction and basic Concepts
Probably the biggest difference between the next generation of computers and
the present will be massive on-line storage and its software. Much of the
computing in industry and goverment will relate to databases which have been
painfully constructed piece by piece, and management effectiveness will relate
to the quality of their organization's data sources and the versatility with
which they can be used.
The role of database-technology as the foundation stone of
future data processing is often not appreciated. The techniques used in many
organization contain the seeds of immense future difficulties. Data
Independence is often thrown to the winds
The development of corporate databases will remain one of the most important data-processing activeties for many years to come. Data is increasingly being regarded as a vital corporate resource which must be organized to maximise their value. Also a vast new demand is growing for database services which organizes, collects and sells data.
The more data the computers have access to, the greater is their potential power. In all walks of life and in all areas of industry, data banks will change the realm of what it is possible for man to do. In centuries hence, historians will look back to the coming of computer data banks and their associated facilities as a step which changed the nature of the evolution of society.
Some of the most impressive corporate growth stories of the generation are largely attributable to the explosive growth in the need for information. As we move to an increasingly information-oriented society, about 20% of the US Gross National Product is devoted to the collection,processing and dissemination of information and knowledge in all its various forms[1].
It has become cheaper to store data on computer files than to store them on paper. Besides printed information, the computer industry has improved its capability to store line drawings, data in facsimile form, photographs, human speech etc. In fact, any form of communication other than the most intimate communications between humans can be transmitted and stored digitally.
File and Database Concepts
File contains a collection of related documents or records
What is a record?
A record usually contains information about an individual or entity. Any
specific record usually consists of a number of attributes or fields
e.g. employee-record
emp_id name designation department salary
In DBMS parlance, a collection of records is also known as a
Database --> repository of information
Overview of DBMS ----> First few pages of James Martin
1. How would you design a database of your class?
2. What kind of information would you store therein, so that it could
provide us with some useful information about class profile?
(Academic perfomance of students and hence corrective actions if necessary.
Addresses of students with their telephone nos, contact ids etc. Strength
and weakness of the class in certain co-curricular activeties like
sports and games e.g, talking about football or cricket one can infer whether
class is strong in batting or bowling, or it has good strikers in the football arena.
Points while designing databases
1. Security
2. Data independence
3. Easy retreival
4. Consistency in design
5. Redundancy
A particularly important consideration in database-design is to
store the data so that they can be used for a wide variety of applications and
so that the way they are used can be changed quickly and easily.
To achieve the flexibility of data usage that is essential in most commercial situations, two aspects of database designs are important. First, the data should be independent of the programs which use them.Second, it should be possible to interrogate and search the database without the lengthy operation of writing programs in conventional programming languages. Database query languages are used.
REFERENCES
1. Markets for Data-base services, Frost and Sullivan Inc., New York, July 1973
2. Computer Data-base Organization, James Martin, PHI (Second edition)