Abstract
The intermediate result cardinality - the number of objects satisfying a condition given in a query - is an important factor for estimating the cost of the query in query optimization. In this paper we show that an object-oriented query often involves partial participation of classes in a relationship. We then present a new technique for estimating the intermediate result cardinality in such a query. Partial participation has not been considered seriously in existing techniques. Since the proposed technique uses detailed statistics to accommodate partial participation, it estimates the intermediate result cardinality more accurately than existing ones. We also show that these statistics are easily obtained by using inherent properties of object-oriented databases.
| Original language | English |
|---|---|
| Pages (from-to) | 253-267 |
| Number of pages | 15 |
| Journal | Information Systems |
| Volume | 21 |
| Issue number | 3 |
| DOIs | |
| State | Published - May 1996 |
Bibliographical note
Funding Information:Acknowledgements - We thank the reviewersf or their careful commentso n an earlier manuscript that helped enhance the clarity of this paper significantly. This work was partially supported by the Korean Ministry of Information and Communicationst hrough Korea Computer and CommunicationsC o. as a part of the ODYSSEUS OODBMS project. It was also partially supported by the Korea Science and Engineering Foundation(KOSEF) through the Center for Artificial Intelligence Research. The last author was supported by the Brain Pool program of the Korean Foundation of Sciencea nd TechnologyS ocieties( KOFST). We would like to acknowledget he careful commentsp rovided by Dr. K. H. Hong.
Keywords
- Cost Model
- Intermediate Results
- Object-Oriented Databases
- Query Optimization
- Selectivities