Krzysztof Stencel

Learn More
Stack-Based Query Language (SBQL) is a model query and programming language for a wide family of object-oriented database models. SBQL is the result of investigations into a uniform theoretical and conceptual basis for object-oriented query languages integrated with programming capabilities and abstractions, including database abstractions: updatable views,(More)
A recursive SQL-1999 query consists of a recursive CTE (Common Table Expression) and a query which uses it. If such a recur-sive query is used in a context of a selection predicate, this predicate can possibly be pushed into the CTE thus limiting the breadth and/or depth of the recursive search. This can happen e.g. after the definition of a view containing(More)
The relational model is the basis for most modern databases, while SQL is the most commonly used query language. However, there are data structures and computational problems that cannot be expressed using SQL-92 queries. Among them are those concerned with the bill-of-material and corporate hierarchies. A newer standard, called the SQL-99, introduced(More)
We propose a new approach to integration of distributed heterogeneous resources on the basis of a canonical object-oriented database model, a query language and updateable database views. Views are used as wrappers/mediators on top of local servers and as a data integration facility for global applications. Views support location, implementation and(More)
Recent years witnessed continuous development of database query languages and object relational mappers. One of the research fields of interest are recursive queries. The first implementations of such queries for SQL has been introduced by Oracle in 1985. However, it was the introduction of recursive Common Table Expressions into the SQL:99 standard that(More)
KsiąŜki w całości ani w części nie wolno powielać ani przekazywać w Ŝaden sposób za pomocą Ŝadnych nośników bez wcześniejszego uzyskania pisemnej zgody Wydawnictwa (The book may not be reproduced or transmitted in whole or in part in any way using any media, without a prior consent in writing from the Publisher) Acknowledgements This book presents a(More)
— When a query jointly addresses very large and very small collections it may happen that an iteration caused by a query operator is driven by a large collection and in each cycle it evaluates a subquery that depends on an element of a small collection. For each such element the result returned by the subquery is the same. In effect, such a subquery is(More)