WinMagic : Subquery Elimination Using Window Aggregation

Database queries often take the form of correlated SQL queries. Correlation refers to the use of values from the outer query block to compute the inner subquery. This is a convenient paradigm for SQL programmers and closely mimics a function invocation paradigm in a typical computer programming language. Queries with correlated subqueries are also often created by SQL generators that translate queries from application domain-specific languages into SQL. Another significant class of queries that use this correlated subquery form is that involving temporal databases using SQL. Performance of these queries is an important consideration particularly in large databases. Several proposals to improve the performance of SQL queries containing correlated subqueries can be found in database literature. One of the main ideas in many of these proposals is to suitably decorrelate the subquery internally to avoid a tuple-at-a-time invocation of the subquery. Magic decorrelation is one method that h...

• Type: Conference
• Year: 2003
• Where: SIGMOD
• Authors: Calisto Zuzarte, Hamid Pirahesh, Wenbin Ma, Qi Cheng, Linqi Liu, Kwai Wong
• Keywords: Correlated Sql Queries, Correlated Subqueries, Database, SIGMOD 2003, Typical Correlated Queries