What are the objectives of database management systems?

Shareability: An ability to share data resources is a fundamental objective of database management. In its fullest interpretation, this means different people and different processes using the same actual data at virtually the same time. Rather far reaching ramifications stem from the stated objective of shareability:

• - Serving differently types of users with varying skill levels
• - Handling different user views of the same stored data.
• - Combining interrelated data
• - Setting standards
• - Controlling concurrent updates so as to maintain data integrity
• - Coordinating restart and recovery operations across multiple users.This list indicates some of the additional problems which arise in managing shared data. A central implication of sharing is that compromise will often be required between conflicting user needs as, for example, in the establishment of a data structure and corresponding storage structure.

Availability: Availability means bringing the data of an organization to the users of that data. They system which manages data resources should be easily accessible to the people within n organization - making the data available when and where it is needed, and in the manner and form in which it is needed. Availability refers to both the data and the DBMS which delivers the data. Availability functions make the database available to users: defining and creating a database, and getting data in and out of a database. These are the direct functions performed by a DBMS. A DBMS should accommodate diversity in the data stored.

The bulk of organization data, as traditionally handled in accounting systems, lied in the enclosed region of historical, internal, financial data. A database management system must be capable of reaching beyond this region to handle greater diversity in the data stored, including subjective data, fragmentary marketing intelligence data, uncertain forecasts and aggregated data, as well as factual marketing, manufacturing, personnel and accounting data.

Evolvability: Evolvability refers to the ability of the DBMS to change in response to growing user needs and advancing technology. Evolvability is the system characteristic that enhances future availability of the data resources. Evolvability is not the same as expandability or extensibility, which imply extending or adding to the system, which then grows ever larger. Evolvability covers expansion or contraction, both of which may occur as the system changes to fit the ever changing needs and desires of the using environment.

Adaptability is a more advanced form of evolvability in which built in algorithms enable a system to change itself, rather than having a change made to it. Adaptability involves purposive, self organizing, or self controlling behavior, that is, self regulation toward a single criterion of success: ultimate, long-term survival. A system exhibiting adaptive behavior actively seeks a particular state or goal by changing itself in response to a change in itself or its environment. Evolvability implies the gradual unfolding, development and growth of a system to better meet the needs of the using environment: and it implies change of the system in response to changing needs and technology. With the present state of technology, such change is externally administered. In the future such change may occur automatically within the system, thus exhibiting adaptive behavior.

Integrity: The importance and pervasiveness of the need to maintain database integrity is rooted in the reality that man is perfect. Destruction, errors and improper disclosure must be anticipated and explicit mechanisms provided for handling them. The three primary facets of database integrity are:-

• protecting the existence of the database
• Maintaining the quality of the database

Ensuring the privacy of the database.In developing DBMSs, the accountant's concept of internal control has been practically ignored. Computer specialists need such concepts to improve database integrity and enhance management confidence.