org.apache.calcite.schema

Interface Statistic

public interface Statistic

Statistics about a Table.

Each of the methods may return null meaning "not known".

See Also:

Statistics

Method Summary

Modifier and Type	Method and Description
default @Nullable List<RelCollation>	getCollations() Returns the collections of columns on which this table is sorted.
default @Nullable RelDistribution	getDistribution() Returns the distribution of the data in this table.
default @Nullable List<ImmutableBitSet>	getKeys() Returns a list of unique keys, or null if no key exist.
default @Nullable List<RelReferentialConstraint>	getReferentialConstraints() Returns the collection of referential constraints (foreign-keys) for this table.
default @Nullable Double	getRowCount() Returns the approximate number of rows in the table.
default boolean	isKey(ImmutableBitSet columns) Returns whether the given set of columns is a unique key, or a superset of a unique key, of the table.

Method Detail

getRowCount

default @Nullable Double getRowCount()

Returns the approximate number of rows in the table.

isKey

default boolean isKey(ImmutableBitSet columns)

Returns whether the given set of columns is a unique key, or a superset of a unique key, of the table.

getKeys

default @Nullable List<ImmutableBitSet> getKeys()

Returns a list of unique keys, or null if no key exist.

getReferentialConstraints

default @Nullable List<RelReferentialConstraint> getReferentialConstraints()

Returns the collection of referential constraints (foreign-keys) for this table.

getCollations

default @Nullable List<RelCollation> getCollations()

Returns the collections of columns on which this table is sorted.

getDistribution

default @Nullable RelDistribution getDistribution()

Returns the distribution of the data in this table.