Research Of Object/relational Mapping (ORM) And Some Implementation Based On C#.NET

Following the continued growth and expansion of software complexity and scale, the quantity of business data has been steadily growing, making all business systems ever relying on databases. Because object-oriented technology is widely used in front software application, and relational database is dominant in the storage mechanism of objects' persistence, we need a mechanism which can map the data of objects which resident in memory to relational database persistently. So the object/relational mapping is the import part of commercial software development.Object-oriented programs using RDBMS as their storage technology means you have to transfer data between the object-oriented view of a business model and the relational schema. Object-oriented model is based on some rationales of software engineering, whereas relational database schema is based on mathematical rationales. The difference between the two foundations, which the object-oriented model and the relational database are based on, causes the imperfect fit between the two technologies, which is called "impedance mismatch". Because of the impedance mismatch between the two technologies, when using RDBMS to store persistent objects we must do the job called "Object/Relational Mapping". O/R mapping is such a process that tries to map the states of objects to the data in RDBMS in order to provide transparent persistent service.This paper mainly studies three aspects as shown below:Theory background of object/relational mapping, object modeling and relational modeling, also the problems that will encountered when mapping object modeling to relational modeling are studied.The ways to map classes in OOP to tables in databases, the strategies to map the relationship between objects are studied. There are the rules of object/relational mapping.The different technologies and solutions of object/relational mapping are studied. It is the real implementation of ORM. There are 3 different tecknologies, based on reflection, based on source generating, based on bytecode manipulation.NHibernate is introduced. NHibernate is the C# .NET edition of Hibernate. It is one of the most successful ORM solutions in recent period.I suggest a new mapping method, which used Attribute in C# .NET.Mapping using Attribute is simpler than using XML file in NHibernate. Mapping...