Query and retrieving semi-structured data from heterogeneous sources by translating structured queries

摘要

A system for querying disparate, heterogeneous data sources over a network, where at least some of the data sources are World Wide Web pages or other semi-structured data sources, includes a query converter, a command transmitter, and a data retriever. The query converter produces, from at least a portion of a query, a set of commands which can be used to interact with a semi-structured data source. The query converter may accept a request in the same form as normally used to access a relational data base, therefore increasing the number of data bases available to a user in a transparent manner. The command transmitter issues the produced commands to the semi-structured data source. The data retriever then retrieves the desired data from the data source. In this manner, structured queries may be used to access both traditional, relational data bases as well as non-traditional semi-structured data bases such as web sites and flat files. The system may also include a request translator and a data translator for providing data context interchange. The request translator translates a request for data having a first data context into a query having a second data context which the query converter described above. The data translator translates data retrieved from the data context of the data source into the data context associated with the request. A related method for querying disparate data sources over a network is also described.