The Design and Implement of Mediator and Wrapper Mechanism in Massive Multi-Database Intergration
|School||Harbin Institute of Technology|
|Course||Computer Science and Technology|
|Keywords||information integration mediator wrapper isomerous data|
With the increase in the amount of Web data and diversification of their forms, How to organize and manage distributed Web data effectively and acquire useful information efficiently from them becomes more and more important.There are many methods in the information integration area.In the paper, a system based in the Mediator and Wrapper is provided to solve the problem of the isomerous data.In the Mediator method, the virtual Mediator is constructed to analyse the query from the users, hide the data information from the data source, do the column mapping, process, divide and send the query.The data dictionary in the Mediator system is stored in the form of the relation in the relational database. The data dictionary is used for the process of the query and the combination of the results. The access of the data dictionary is independent to read or write the data dictionary which is in the form of the relation.The Wrapper system is constructed to wrapper the data from the data source, receive the query from the Mediator system, do the process of the query , translate the columns and do the process of the results including the byte order and the null-value. To scan the large data in one time ,some strategies are used.The MDL and WDL language are explained which are used to maintain Mediator and Wrapper. The MDL language has not only the creation of Mediator, but also has the registration of the Wrapper. The WDL language is used to maintain the Wrapper including the mapping of the column and the information of the columns.In the paper, there is an example to introduce the whole system, creating the real Mediator and Wrapper. The query is passed in the modules of the system to explain how to solve the problem of the In the paper, there is an example to introduce the whole system, creating the real Mediator and Wrapper. The query is passed in the modules of the system to explain how to solve the problem of the isomerous data.In a summary , the virtual method can integrate the isomerous data.