A rule-based view of query optimization
SIGMOD '87 Proceedings of the 1987 ACM SIGMOD international conference on Management of data
Rule-based optimization and query processing in an extensible geometric database system
ACM Transactions on Database Systems (TODS)
PCTE: the standard for open repositories
PCTE: the standard for open repositories
EDBT '94 Proceedings of the 4th international conference on extending database technology: Advances in database technology
Evaluating queries with generalized path expressions
SIGMOD '96 Proceedings of the 1996 ACM SIGMOD international conference on Management of data
ACM Computing Surveys (CSUR)
Document retrieval facilities for repository-based system development environments
SIGIR '96 Proceedings of the 19th annual international ACM SIGIR conference on Research and development in information retrieval
ACM Computing Surveys (CSUR)
Query Processing for Advanced Database Systems
Query Processing for Advanced Database Systems
Object Database Standard: ODMG-93
Object Database Standard: ODMG-93
Implementing an Interpreter for Functional Rules in a Query Optimizer
VLDB '88 Proceedings of the 14th International Conference on Very Large Data Bases
Extending a Spatial Access Structure to Support Additional Standard Attributes
SSD '95 Proceedings of the 4th International Symposium on Advances in Spatial Databases
Query Optimization in the CROQUE Project
DEXA '96 Proceedings of the 7th International Conference on Database and Expert Systems Applications
A Heuristic Approach for Optimization of Path Expressions
DEXA '95 Proceedings of the 6th International Conference on Database and Expert Systems Applications
P-OQL: an OQL-oriented query language for Pcte
SEE '95 Proceedings of the 1995 Software Engineering Environment Conferences
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One of the main characteristics of object-oriented database management systems is the explicit representation of relationships between objects. A simple example for a query addressing these relationships arises, if we assume the object types Company, and Division with the relationship has division from Company to Division. In this case a query might ask for the companies which have a division called "strategy". The query might start with the companies and navigate to the divisions which can be reached via the has division relationship. Finally the query has to check if the name attribute of the Division object is "strategy". Since there is no direct condition for the companies in the query, this query execution will be costly. If we assume that there is a reverse relationship division of from Division to Company, an alternative execution plan might start with the "strategy" divisions and follow this reverse relationship. In this case an index structure for the name attribute of the Division objects can be exploited to speed up query processing. In the present paper we describe a query optimizer which exploits this potential invertibility of navigational operations in queries. Our approach is based on, but not limited to the context of the ISO and ECMA standard PCTE and P-OQL.