class Step extends DefaultEdge
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
.
Modifier and Type | Class and Description |
---|---|
(package private) static class |
Step.Factory
Creates
Step instances. |
Modifier and Type | Field and Description |
---|---|
(package private) java.util.List<IntPair> |
keys |
source, target
Constructor and Description |
---|
Step(LatticeTable source,
LatticeTable target,
java.util.List<IntPair> keys) |
Modifier and Type | Method and Description |
---|---|
private double |
cardinality(SqlStatisticProvider statisticProvider,
LatticeTable table)
Temporary method.
|
private static int |
compare(RelOptTable table1,
java.util.List<java.lang.Integer> columns1,
RelOptTable table2,
java.util.List<java.lang.Integer> columns2)
Arbitrarily compares (table, columns).
|
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() |
factory
final java.util.List<IntPair> keys
Step(LatticeTable source, LatticeTable target, java.util.List<IntPair> keys)
public int hashCode()
hashCode
in class DefaultEdge
public boolean equals(java.lang.Object obj)
equals
in class DefaultEdge
public java.lang.String toString()
toString
in class java.lang.Object
LatticeTable source()
LatticeTable target()
boolean isBackwards(SqlStatisticProvider statisticProvider)
private static int compare(RelOptTable table1, java.util.List<java.lang.Integer> columns1, RelOptTable table2, java.util.List<java.lang.Integer> columns2)
private double cardinality(SqlStatisticProvider statisticProvider, LatticeTable table)
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