Network DBMS

Details

The typical representative is Integrated Database Management System (IDMS) appeared in the seventies. Among the domestic DBMS based on a network model it should be noted CronosPRO of Cronos-Inform company provided in the early nineties.

Network approach to data structure is expansion hierarchical.

The network DB consists of a record set and a set of communications between these records. On formation of communication of special restrictions it is not imposed. In hierarchical structures record descendant should have in the accuracy of one ancestor, and in a network data structure the descendant can have any number of ancestors.

Advantages

The advantage of a network model of data is the possibility of effective implementation on indicators of costs of memory and efficiency. In comparison with hierarchical model the network model gives great opportunities in sense of validity of formation of any communications. Within network DBMS also hierarchical datalogichesky models easily are implemented. Network DBMS support difficult ratios between data types that does them suitable in different applications. Thus, the following belongs to main advantages of network DBMS:

• processing of large volumes of information (a possibility of creation on the basis of such DBMS of "data warehouses");
• support of analytical data processing;
• effective implementation of data processing on indicators of costs of memory and efficiency.

Shortcomings

Users of network DBMS are limited to the communications determined for them by developers of DB applications. It is similar hierarchical, network DBMS assume development of DB applications by experienced programmers and systems analysts.

Also the high complexity and rigidity of the scheme DB constructed on its basis and also complexity for understanding and accomplishment of information processing in a DB by the normal user belongs to shortcomings of a network model of data. Besides, in a network model of data controls of integrity of communications owing to validity of establishment of any communications between records are loosened.

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