New DAO pattern with dynamic extensibility
Ping Zeng · Journal of Computer Applications · 2007
Currently the existing Data Access Object(DAO)patterns have several limitations.First,the interface of the patterns and business objects is tightly-coupled,which seriously affects the dynamic extensibility of software systems.Second,the patterns have duplicated implementation codes,which adds to the difficulty of system maintenance.To solve these problems,a new DAO pattern with stronger independency and dynamic extensibility was proposed in the paper based on the concepts of data binding,meta data and meta model.Finally,an example was given to illustrate the using process of the new DAO pattern.The greatest advantages of the new DAO pattern are as follows.If any business object is needed to add to the system,we don't have to modify any codes of the class DAOFactory.All that we need to do is to modify the mapping file.Furthermore,because we have only one DAO implementation class to accomplish all the data access to business objects,if some SQL statements are needed to be modified,all we need to do is to modify the DAO implementation class but not modify any business objects.