Why do we need database?
As we all know Database has a availability of a storage system, the most obvious of these being persistence. To sum it up, we can identify the following reasons for wanting a Database Management Systems short for DBMS:
Before we go further, we should clearly define a few of the central terms that are going to be used in the following (some of them will have appeared already), to make it clear what we mean by them.
• Software Maintenance is a evolution (change) of software after initial delivery, the amount of work is distributed with 17% for corrective, 18% for adaptive and 60% for perfective changes.
• Software Object or Softwate configuration Item is an object which is not necessarily software in itself, but has been produced, or is being used, in a software project. It is also placed in computer storage (database, file system, memory). An object also has a type, and it usually has some data Attributes.
Typical examples of software objects include source files, libraries, compilers, requirement specifications, user manuals, test scripts, programmers, change requests, customer records and so on.
• Configuration is a complete and consistent collection of objects and relationships between them that together form a whole with some meaningful properties. A configuration is not any random collection there has to be reason why we want to define the collection itself as an object. A configuration is thus a special case of a composite object, as defined above.
The typical configuration is a program system which is built up of subsystems, each of which again is built up of modules. Configurations can also collect items along other dimensions. For example, a configuration for a complete software system deliverable could include executable programs, installation manual, user documentation, and registration forms. A similar configuration for the same system, but for internal use, may include source code, requirements specification, design documents etc.
• Transactions is an envelope for a set of operations against a database. In traditional database use, this set of operations together constitute a single logical database operation as seen by the user.
In addition to basic requirements of any DBMS, such as reliability, performance, multiuser access etc., we can identify a number of requirements pertaining to its use in a see.
