org.apache.flink.table.planner.plan.metadata

Interface FlinkMetadata.UniqueGroups

All Superinterfaces:

org.apache.calcite.rel.metadata.Metadata

Enclosing class:

FlinkMetadata

public static interface FlinkMetadata.UniqueGroups
extends org.apache.calcite.rel.metadata.Metadata

Metadata about the (minimum) unique groups of the given columns from a specified relational expression.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static interface	FlinkMetadata.UniqueGroups.Handler Handler API.

Field Summary

Fields

Modifier and Type	Field and Description
static org.apache.calcite.rel.metadata.MetadataDef<FlinkMetadata.UniqueGroups>	DEF
static Method	METHOD

Method Summary

Modifier and Type	Method and Description
org.apache.calcite.util.ImmutableBitSet	getUniqueGroups(org.apache.calcite.util.ImmutableBitSet columns) Returns the (minimum) unique groups of the given columns from a specified relational expression.

Methods inherited from interface org.apache.calcite.rel.metadata.Metadata

rel

Field Detail

METHOD

static final Method METHOD

DEF

static final org.apache.calcite.rel.metadata.MetadataDef<FlinkMetadata.UniqueGroups> DEF

Method Detail

getUniqueGroups

org.apache.calcite.util.ImmutableBitSet getUniqueGroups(org.apache.calcite.util.ImmutableBitSet columns)

Returns the (minimum) unique groups of the given columns from a specified relational expression.

Parameters:

columns - the given columns in a specified relational expression. The given columns should not be null.

Returns:

the (minimum) unique columns which should be a sub-collection of the given columns, and should not be null or empty. If none unique columns can be found, return the given columns.