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 List<RelCollation>	getCollations() Returns the collections of columns on which this table is sorted.
default RelDistribution	getDistribution() Returns the distribution of the data in this table.
default List<ImmutableBitSet>	getKeys() Returns a list of unique keys, or null if no key exist.
default List<RelReferentialConstraint>	getReferentialConstraints() Returns the collection of referential constraints (foreign-keys) for this table.
default 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 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 List<ImmutableBitSet> getKeys()

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

getReferentialConstraints

default List<RelReferentialConstraint> getReferentialConstraints()

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

getCollations

default List<RelCollation> getCollations()

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

getDistribution

default RelDistribution getDistribution()

Returns the distribution of the data in this table.