Class RelSubset

All Implemented Interfaces:
Cloneable, RelOptNode, RelNode

public class RelSubset
extends AbstractRelNode
Subset of an equivalence class where all relational expressions have the same physical properties.

Physical properties are instances of the RelTraitSet, and consist of traits such as calling convention and collation (sort-order).

For some traits, a relational expression can have more than one instance. For example, R can be sorted on both [X] and [Y, Z]. In which case, R would belong to the sub-sets for [X] and [Y, Z]; and also the leading edges [Y] and [].

See Also:
RelNode, RelSet, RelTrait