DBMS: Methods of the organization

File-server

During the work about the file - a server system processing of all data happens in workplaces, and the server is used only as the separated drive. Each user directly uses information and makes changes to data files and to index files. At large volumes of data and work in the multi-user mode high-speed performance  — the more users significantly decreases, the requirements to separation of data are higher. Besides, there can be a damage of databases. For example, at the time of file recording there can be a failure of network or accident of a power supply. In this case the computer of the user interrupts work, the database can be damaged, and the index file  — destroyed. Reindexation which needs to be carried out after similar failures can last several hours. The listed shortcomings force the users working in network to refuse from the file - server DBMS.

Examples of DBMS the file - the server organization is Borland Paradox, Microsoft Access, Microsoft Visual FoxPro.

Client-server

When using a client-server method of the organization all work with the database happens on the server and does not depend on failures at workstations. All requests for file recording are intercepted by the server. Changes are only made to the file after the server receives the message that adjustment of the file is complete. It excludes damage of index files and significantly increases high-speed performance of a system.

Client-server DBMS also have a number of shortcomings:

• high requirements to capacity of communication links with the server;
• weak data protection from cracking, in particular from unfair users of a system;
• high complexity of administration and setup of jobs of users of a system;
• need to use rather powerful computers on client places;
• complexity of integration with legacy systems;
• complexity of system development because of need to perform business logic and to provide the interface with the user in one program.

Among client-server DBMS such products as IBM DB2, the MS SQL Server, Oracle, MySQL are most widespread.

Built in

The built-in management system for the database  is a system which can be connected with the client application so that the application and DBMS worked in a uniform address space. Together with an embedded database the application can be unrolled as the uniform program which is functional, effective and autonomous. Thanks to linking of the application with the database, an applied system benefits from decrease in the general complexity and reduction of costs for administration. In many cases the built-in management system for the database  — the most suitable option for systems with limited resources. However, the built-in DBMS often are suitable only for solving of tasks of the narrow specification.

Vstraivayev are such DBMS as InterBase SMP, BerkeleyDB, OpenEdge.

See Also

• DBMS

Links

• Advantages the Client-server before Fayl-Servernoy technology
• Creation of the built-in DB