Package org.apache.calcite.materialize

Class Step

java.lang.Object

org.apache.calcite.util.graph.DefaultEdge

org.apache.calcite.materialize.Step

class Step
extends DefaultEdge

Edge in the join graph.

It is directed: the "parent" must be the "many" side containing the foreign key, and the "target" is the "one" side containing the primary key. For example, EMP → DEPT.

When created via LatticeSpace.addEdge(LatticeTable, LatticeTable, List) it is unique within the LatticeSpace.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
(package private) static class	Step.Factory	Creates Step instances.

Field Summary

Fields

Modifier and Type	Field	Description
(package private) java.util.List<IntPair>	keys

Fields inherited from class org.apache.calcite.util.graph.DefaultEdge

source, target

Constructor Summary

Constructors

Constructor	Description
Step(LatticeTable source, LatticeTable target, java.util.List<IntPair> keys)

Method Summary

Modifier and Type	Method	Description
private double	cardinality(SqlStatisticProvider statisticProvider, LatticeTable table)	Temporary method.
boolean	equals(java.lang.Object obj)
int	hashCode()
(package private) boolean	isBackwards(SqlStatisticProvider statisticProvider)
(package private) LatticeTable	source()
(package private) LatticeTable	target()
java.lang.String	toString()

Methods inherited from class org.apache.calcite.util.graph.DefaultEdge

factory

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

keys

final java.util.List<IntPair> keys

Constructor Detail

Step

Step(LatticeTable source,
     LatticeTable target,
     java.util.List<IntPair> keys)

Method Detail

hashCode

public int hashCode()

Overrides:

hashCode in class DefaultEdge

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class DefaultEdge

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

source

LatticeTable source()

target

LatticeTable target()

isBackwards

boolean isBackwards(SqlStatisticProvider statisticProvider)

cardinality

private double cardinality(SqlStatisticProvider statisticProvider,
                           LatticeTable table)

Temporary method. We should use (inferred) primary keys to figure out the direction of steps.