An Object - Oriented View Onto Public , Heterogeneous

Even though companies maintain highly-structured, traditional business data in relational databases, large amounts of information are available in semi-structured text sources, such as indexed online newspapers , patent information, literature citations or business prooles. This information is ooered by commercial providers who maintain complete control over access language, schemas and update capabilities. One way to unify access to all of this material is to make it look like a collection of objects in an object-oriented database. We have prototyped such a view onto an information service that provides some 400 full-text, bibliographic and numeric databases. We explain how the illusion of object-orientedness is put together and how it is maintained in queries. We also show how we use the object-oriented approach to handle some classes of schema heterogeneity. Our query language is OSQL, an object-oriented extension to SQL.