Because relational systems are based on rigorous mathematical principles, algebraic simplification and term reduction can be made for most queries. Semantically equivalent operations may be substituted for analytically more difficult operations to simplify processing. Typically, these semantically equivalent rewrites cannot be specified in the query itself, examples being the substitution of a join index for an explicitly specified join operation and the pushing of projections.
The following examples show how Vantage rewrites submitted queries for faster processing.
- Converting ANSI Join Syntax to Comma Join Syntax
- Projection Pushdown
- IN-List Rewrite
- Outer Join-to-Inner Join Conversion
- View Folding
- Predicate Simplification
- Predicate Pushdown and Pullup
- Eliminating Set Operation Branches
- Eliminating Redundant Joins
- Pushing Joins into UNION ALL Branches
- Other Query Rewrites
- Predicate Marshaling
- View Materialization and Other Database Object Substitutions