Abstract
| Original language | English |
|---|---|
| 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 |
|---|---|
| Publisher | Springer |
| Volume | 779 |
| ISSN (Print) | 0302-9743 |
| ISSN (Electronic) | 1611-3349 |
Conference
| Conference | 4th International Conference on Extending Database Technology, EDBT 1994 |
|---|---|
| Abbreviated title | EDBT |
| Country | United Kingdom |
| City | Cambridge |
| Period | 28/03/94 → 31/03/94 |
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Keywords
- METIS-118956
- IR-96073
Cite this
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Optimization of nested queries in a complex object model. / Steenhagen, H.J.; Steenhagen, Hennie J.; Apers, Peter M.G.; Blanken, Henk.
Advances in database technology - EDBT '94. ed. / Matthias Jarke; Janis Bubenko; Keith Jeffery. Berlin : Springer, 1994. p. 337-350 (Lecture notes in computer science; Vol. 779).Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › Academic › peer-review
TY - GEN
T1 - Optimization of nested queries in a complex object model
AU - Steenhagen, H.J.
AU - Steenhagen, Hennie J.
AU - Apers, Peter M.G.
AU - Blanken, Henk
PY - 1994/3/28
Y1 - 1994/3/28
N2 - 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.
AB - 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.
KW - METIS-118956
KW - IR-96073
U2 - 10.1007/3-540-57818-8_62
DO - 10.1007/3-540-57818-8_62
M3 - Conference contribution
SN - 3-540-57818-8
T3 - Lecture notes in computer science
SP - 337
EP - 350
BT - Advances in database technology - EDBT '94
A2 - Jarke, Matthias
A2 - Bubenko, Janis
A2 - Jeffery, Keith
PB - Springer
CY - Berlin
ER -