Abstract

We propose a technique to answer OQL query expressions using OQL view expressions. The technique for reformulation is based on the extended pattern-matching of well typed expressions. It uses an algorithm FindSubquery, which determines if the OQL query can be rewritten so that it uses the OQL view expression. If so, the query can be answered using the view. Our research has the following features: we handle queries and views that are general OQL expressions; we handle template views (that are expressed over variables); we can generalize a view over the type hierarchy; we handle disjunctions in the view; and we use integrity constraints while matching the query and the view. 1 Introduction There has been much research on answering queries using relational views. The issues are summarized in [Mumick95]. However, there has been little research on the object data model and query languages. The object model, e.g., ODMG, extends the relational model with features such as a type hierarchy, c...

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