org.apache.calcite.statistic

Enum MapSqlStatisticProvider

java.lang.Object

java.lang.Enum<MapSqlStatisticProvider>

org.apache.calcite.statistic.MapSqlStatisticProvider

All Implemented Interfaces:

Serializable, Comparable<MapSqlStatisticProvider>, SqlStatisticProvider

public enum MapSqlStatisticProvider
extends Enum<MapSqlStatisticProvider>
implements SqlStatisticProvider

Implementation of SqlStatisticProvider that looks up values in a table.

Only for testing.

Enum Constant Summary

Enum Constants

Enum Constant and Description
INSTANCE

Method Summary

Modifier and Type	Method and Description
boolean	isForeignKey(RelOptTable fromTable, List<Integer> fromColumns, RelOptTable toTable, List<Integer> toColumns) Returns whether a join is a foreign key; that is, whether every row in the referencing table is matched by at least one row in the referenced table.
boolean	isKey(RelOptTable table, List<Integer> columns) Returns whether a collection of columns is a unique (or primary) key.
double	tableCardinality(RelOptTable table) Returns an estimate of the number of rows in table.
static MapSqlStatisticProvider	valueOf(String name) Returns the enum constant of this type with the specified name.
static MapSqlStatisticProvider[]	values() Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

INSTANCE

public static final MapSqlStatisticProvider INSTANCE

Method Detail

values

public static MapSqlStatisticProvider[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (MapSqlStatisticProvider c : MapSqlStatisticProvider.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static MapSqlStatisticProvider valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum type has no constant with the specified name

NullPointerException - if the argument is null

tableCardinality

public double tableCardinality(RelOptTable table)

Description copied from interface: SqlStatisticProvider

Returns an estimate of the number of rows in table.

Specified by:

tableCardinality in interface SqlStatisticProvider

isForeignKey

public boolean isForeignKey(RelOptTable fromTable,
                            List<Integer> fromColumns,
                            RelOptTable toTable,
                            List<Integer> toColumns)

Description copied from interface: SqlStatisticProvider

Returns whether a join is a foreign key; that is, whether every row in the referencing table is matched by at least one row in the referenced table.

For example, isForeignKey(EMP, [DEPTNO], DEPT, [DEPTNO]) returns true.

To change "at least one" to "exactly one", you also need to call SqlStatisticProvider.isKey(org.apache.calcite.plan.RelOptTable, java.util.List<java.lang.Integer>).

Specified by:

isForeignKey in interface SqlStatisticProvider

isKey

public boolean isKey(RelOptTable table,
                     List<Integer> columns)

Description copied from interface: SqlStatisticProvider

Returns whether a collection of columns is a unique (or primary) key.

For example, isKey(EMP, [DEPTNO] returns true;

For example, isKey(DEPT, [DEPTNO] returns false.

Specified by:

isKey in interface SqlStatisticProvider