The Research And Design Of Fast Persistence Layer For Maping Object To Rational Database

The things in the world can be presented by object-oriented model. The complex software system can be well decribed and designed by object-oriented model. In software system some objects should be stored for future use. Because the theory of ralational database is well delvelopped, lots of companies are using ralational database for storing data, therefore ralational database can also save the objects.The object paradigm is based on building applications out of objects that have both data and behavior, whereas the relational paradigm is based on storing data. The "impedance mismatch" comes into play when you look at the preferred approach to access.To persistence the objects there are two common approach.one approach is that Structured Query Language (SQL) codeis embedded in the source code of your classes. The other approach is that SQL statements for your business classes are encapsulated in one or more "data classes." The disadvantage is that it directly couples your business classes with the schema of your relational database, implying that a simple change such as renaming a column or porting to another database results in a rework of your source code.For resolving the problem mentioned above.the paper gives out a robust persistence layer that maps objects to persistence mechanisms in such a manner that simple changes to the relational schema do not affect your object-oriented code.because there is a mapping dictionary in the persistence layer.The advantage of this approach is that your application programmers do not need to know a thing about the schema of the relational database. The disadvantage is that there is a performance impact to the applications.in the paper, we research some technechs such as the cursor, proxy and buffer to improve the performance. the experience showes thar the fast persistence layer can well persistence the objects, that the mismatch between object-oriented and ralational database is elimated for the most, that independency between object-oriented and ralational database is implented.also because of the mapping dictionary ,the persistence layer has the migration.