网状数据库

一个从网状数据库模式到关系数据库模式的转换算法

A conversion algorithm frcm DBTG schema to relation DBMS schema

该系统采用VAX-11DBMS网状数据库技术，具有数据独立性、共享性、保密性和数据完整一致的特点。

This system uses VAX-11 network DBMS and has the features of data independence , data sharing , data security and data integrity .

数据库技术经历了从层次数据库、网状数据库到关系数据库以及面向对象数据库的发展，已成为计算机信息系统中的重要基础和支柱，并在传统的商业和事务处理等领域内趋于成熟。

The technology of database develops from hiberarchy database , retiform database to relational database , even OO database , that has become to the base of information system .

从时间上看，空间数据库技术的发展可以划分为四代：文件系统、层次或网状数据库、关系数据库、面向对象数据库。

As viewed from the time , The development on technology can be concluded to four periods : file system hiberarchy or network model database relational database and object oriented database .

本文介绍了在网状型数据库IDMS上实现的安全技术和恢复数据库的过程。

In this article , the security and recovery techniques are introduced , which are implemented on a network data base-IDMS .