A query based approach for integrating heterogeneous data sources
Ruxandra Domenig, Klaus R. Dittrich · 2000
Data available on-line toda y is spread over heterogeneous data sources like traditional databases or sources of various forms containing unstructured and semistructured data.Obviously , the \tec hnical" a vailabilit y alone is not at all sufcien t for making meaningful use of the existing information, and thus the problem of eectively and eÆciently accessing and querying heterogeneous data is an important research issue.One main approach i s t o i n tegrate the data sources and oer users an a priori de ned global schema.Alternatively, there are approaches which implement tools for giving users the possibility to de ne the global schema themselves.We propose a new approach where heterogeneous sources can be queried through a uni ed interface and underlying sources are in tegrated b y means of a query language only .In this paper, we presen t extensions to OQL whic h allo w to query structurally heterogeneous data, i.e. structured, semistructured and unstructured data alik e, and to integrate data on-the-y.We also deal with issues of the extensive meta information about sources that is needed for integration.