Abstract
Transformation of nested SQL queries into join queries is advantageous because a nested SQL query can be looked upon as a nested-loop join, which is just one of the several join implementations that may be available in a relational DBMS. In join queries, dangling (unmatched) operand tuples are lost, which causes a problem in transforming nested queries having the aggregate function COUNT between query blocks-a problem that has become well-known as the COUNT bug. In the relational context, the outerjoin has been employed to solve the COUNT bug. In complex object models supporting an SQL-like query language, transformation of nested queries into join queries is an important optimization issue as well. The COUNT bug turns out to be a special case of a general problem being revealed in a complex object model. To solve the more general problem, we introduce the nest join operator, which is a generalization of the outerjoin for complex objects.
Original language | English |
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Title of host publication | Advances in database technology - EDBT '94 |
Editors | Matthias Jarke, Janis Bubenko, Keith Jeffery |
Place of Publication | Berlin |
Publisher | Springer |
Pages | 337-350 |
ISBN (Print) | 3-540-57818-8 |
DOIs | |
Publication status | Published - 28 Mar 1994 |
Event | 4th International Conference on Extending Database Technology, EDBT 1994 - Cambridge, United Kingdom Duration: 28 Mar 1994 → 31 Mar 1994 Conference number: 4 |
Publication series
Name | Lecture notes in computer science |
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Publisher | Springer |
Volume | 779 |
ISSN (Print) | 0302-9743 |
ISSN (Electronic) | 1611-3349 |
Conference
Conference | 4th International Conference on Extending Database Technology, EDBT 1994 |
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Abbreviated title | EDBT |
Country/Territory | United Kingdom |
City | Cambridge |
Period | 28/03/94 → 31/03/94 |
Keywords
- METIS-118956
- IR-96073