The Research Of Device Management Information System Object Relational Mapping Technology Based On NHibernate

Information systems universally use the object-oriented technology for modeling the business logic and RDBMS for data maintenance and management. However there exists distinguish differences between the object-oriented model and the relational model, which adds to difficulties of system development. Making use of ORM(Object Relational Mapping) technology, a data-persistence layer with high reliability will be established, which provides a nice solution for this problem.This paper introduces the technique features of ORM, gives a comprehensive comparison between the functions of diverse ORM frameworks. In the progress of the engineering practice of the device management information system, a data-persistence layer is set up based on NHibernate, and successfully makes the object-oriented model upper and the relational model below structurally connected and functionally mapped with each other, which well keeps the integrity of the system.Providing the complexity of the device information, this paper accomplishes a normalized and self-contained device data model within the sense of business requirements, which especially stresses the device category level, device composition and the structure of device properties. This device data model allows to dynamically and easily change the scopes of devices and device properties, taking on good scalability.According that different kinds of devices distribute in different departments, a business model of double catalog trees is set up, as well as the concept of association consistency, on the ground of which is carried out a study about different kinds of algorithms for maintaining the association consistency, and based on performance-tuning abilities NHibernate provides, the algorithms are enhanced with an improvement by clearing the cache and loading the data in advance at proper moments.