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a software system that facilitates the creation and maintenance and use of an electronic database

a software system that facilitates the creation and maintenance and use of an electronic database

Software designed to store, manipulate, manage, and control data for specific uses.

(DBMS) A suite of programs which typically managelarge structured sets of persistent data, offering ad hocquery facilities to many users. They are widely used inbusiness applications.A database management system (DBMS) can be an extremelycomplex set of software programs that controls theorganisation, storage and retrieval of data (fields, recordsand files) in a database. It also controls the security andintegrity of the database. The DBMS accepts requests for datafrom the application program and instructs the operatingsystem to transfer the appropriate data.When a DBMS is used, information systems can be changed muchmore easily as the organisation's information requirementschange. New categories of data can be added to the databasewithout disruption to the existing system.Data security prevents unauthorised users from viewing orupdating the database. Using passwords, users are allowedaccess to the entire database or subsets of the database,called subschemas (pronounced "sub-skeema"). For example, anemployee database can contain all the data about an individualemployee, but one group of users may be authorised to viewonly payroll data, while others are allowed access to onlywork history and medical data.The DBMS can maintain the integrity of the database by notallowing more than one user to update the same record at thesame time. The DBMS can keep duplicate records out of thedatabase; for example, no two customers with the same customernumbers (key fields) can be entered into the database.Query languages and report writers allow users tointeractively interrogate the database and analyse its data.If the DBMS provides a way to interactively enter and updatethe database, as well as interrogate it, this capabilityallows for managing personal databases. However, it may notleave an audit trail of actions or provide the kinds ofcontrols necessary in a multi-user organisation. Thesecontrols are only available when a set of application programsare customised for each data entry and updating function.A business information system is made up of subjects(customers, employees, vendors, etc.) and activities (orders,payments, purchases, etc.). Database design is the process ofdeciding how to organize this data into record types and howthe record types will relate to each other. The DBMS shouldmirror the organisation's data structure and processtransactions efficiently.Organisations may use one kind of DBMS for daily transactionprocessing and then move the detail onto another computer thatuses another DBMS better suited for random inquiries andanalysis. Overall systems design decisions are performed bydata administrators and systems analysts. Detailed databasedesign is performed by database administrators.The three most common organisations are the hierarchicaldatabase, network database and relational database. Adatabase management system may provide one, two or all threemethods. Inverted lists and other methods are also used. Themost suitable structure depends on the application and on thetransaction rate and the number of inquiries that will bemade.Database machines are specially designed computers that holdthe actual databases and run only the DBMS and relatedsoftware. Connected to one or more mainframes via ahigh-speed channel, database machines are used in large volumetransaction processing environments. Database machines have alarge number of DBMS functions built into the hardware andalso provide special techniques for accessing the diskscontaining the databases, such as using multiple processorsconcurrently for high-speed searches.The world of information is made up of data, text, picturesand voice. Many DBMSs manage text as well as data, but veryfew manage both with equal proficiency. Throughout the 1990s,as storage capacities continue to increase, DBMSs will beginto integrate all forms of information. Eventually, it will becommon for a database to handle data, text, graphics, voiceand video with the same ease as today's systems handle data.See also: intelligent database.