Data Storage

LECTIONS

Lecture on

ORGANIZATION OF THE DATA BASE

Producer: St. Cherepica L.S.

Lecture plan

1. Physical access to the database

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1. Physical Access to the DATA Base

1.1. Scope of modern databases and facilities for their location

The physical access to the database is presented in rice. 1.

The user interacts with the database system by launching instructions. The strategic selector will transform the user team into the most effective form for implementation. The converted requirement shall activate the buffer control device controlling the movement of data between operational memory and disk. The file controller supports the buffer controller by managing the disk and data structures. In addition to user data, the disc contains a data dictionary.

Strategic Selter - software that transforms user demand into an effective form.

Buffer management (disk control) is software to control the movement of data between operational memory and disk.

File dispatcher, software, disk and data structure.

The data log is part of the CBD, which defines the user data structure and the possibilities for their use.

Operational memory is a memorial located in the processor hub; it is used to memorize data available for operation.

The rapid operation of the database management system is largely determined by the physical data structures used and the extent to which the system operates effectively. With a successful physical device of the database, data can be extracted, updated, manipulated in a short time.

In order to achieve this, important tasks of building and managing the database should be fulfilled. These include:

Using the way files are located on the disk;

§ Determining the required volume of disc memory;

§ Distribution of information on the disc.

Choice a way to place files on the CD. Most CBDs allow the system administrator to select one of the means of accommodation Database files Discs: on " clean " disks or in the file system.

The merit of storing information on " clean " discs is that external memory is being used more efficiently and is generally increasing the productivity of disk exchange. Savings in external memory between 10 and 20 per cent are achieved by eliminating the need for a file system itself. In UNIX, for example, the file system service information is approximately 10 per cent of the disc capacity.