Metadata is suitable for the place of the object / relational mapping (0/RM) tools.
0/RM tool database table and column mapping for the application of the class and field. Or, 0/RM tool metadata establish mapping relations between metadata of database and metadata of the class. In this case, each field of the class is mapped to
Before the introduction of the data persistence layer framework, the system development process use the traditional two-tier model, the development of business functions cannot cast aside the shackles of the database. How to make the complex data persistence and convenient to inquiry and operation become the urgent needs in the software development field. Now there are many excellent O/R Mapping components to solve the problem of data persistence, change the traditional two-tier into three-tier or multi-tier model, such as Hibernate and IBATIS persistence framework. In the system of business logical stability, infrequent database model change, the above persistence framework is undoubtedly a very good solution. When the system development process, need to change the database model, the first need to change the database model, then the configuration file, then the persistence layer framework, in the end modified class objects, business logic and presentation layer. Complex changes brought inconvenience for the development of the system.