The control system of databases is a difficult set of programs which operate the organisation, storage, management and search of data in a database. The control system of databases is characterised according to structures of their data or types. It shows a number of prewritten programs, which are used to keep, update and restore a database.



The control system of databases includes:

Modelling language to define the scheme of each database which accept in a control system of databases, according to model of data of a control system of databases.

Four types of the organisation most general - hierarchical, a network, relative and object models. The turned lists and other methods also are used. The given control system of a database can provide one or more quantity of models. The optimum structure depends on a natural data structure of the statement and from statement requirements (which include operational norm (speed), reliability, maintainability, scale, etc.).

For today in use by dominating model the special package of data enclosed in SQL is. And it, despite objections tourists which believe, that the given model - corruption of relative model as it breaks some the fundamental principles for the sake of a practicality and work. It is a lot of DBMSs also support Open Possibility of connection of Database API, which supports a standard way for programmers to get access to a control system of databases.

Structures of data (area, reports, files and objects) are optimised to deal very much a considerable quantity of data, and are stored on the constant device of a data storage (which rather slow access in comparison with changeable main memory means).

Safety of data interferes with that unauthorized users have considered or have updated a database. Using passwords, to users resolve access to all database or subsets of the named subcircuit. For example, the database of the employee can contain all data about the individual employee, but one group of users can be authorised to consider only pay-sheet data, while another resolve access only to work with histories and medical data.

If the control system of databases provides an input way to an interactive mode and database updatings this ability considers supervising personal databases. However, it, probably, does not leave an auditor trace of actions or provides other kinds of the control facilities necessary in the multiuser organisation. These control facilities only are accessible, when a number of applied programs are adjusted for each input of data and function updating.

The control system of databases can support integrity of a database, not resolving it is more than one user to update same report at the same time. The control system of databases can help to prevent double reports through unique restrictions of an index. For example, no two clients with the same numbers of the client (key fields) can be entered into a database.

The control system of databases accepts inquiries about data from the applied program and instructs operational system to transfer corresponding data.

When the control system of databases is used, information systems can be changed much easier as information change of requirements of the organisation. New categories of data can be added to a database without destruction to existing system.

The organisations can use one kind of a control system of databases for daily operational processing and then transfer details to other computer which uses other control system of databases which satisfy for casual inquiries and the analysis is better. Full systems intend to define, that decisions are executed by managers of data and analysts of systems. The detailed project of a database is executed by managers of a database.

Servers of a database-it especially developed computers which hold actual databases and operate only a control system of databases and the connected software. Database servers usually are computers of the multiprocessor with the disk sets of ATTACK used for steady storage. Connected with one or more servers through the high-speed channel, accelerators of a database of hardware also are used in the big transaction of volume processing environment.

DBMSs are found in a basis of the majority of statements of a database. Sometimes DBMSs are constructed round a private kernel of multimanagement by problems with the built in network support though now these functions leave to operational system.