org.apache.calcite.schema.impl

Class StarTable

java.lang.Object

org.apache.calcite.schema.impl.AbstractTable

org.apache.calcite.schema.impl.StarTable

All Implemented Interfaces:

Table, TranslatableTable

public class StarTable
extends AbstractTable
implements TranslatableTable

Virtual table that is composed of two or more tables joined together.

Star tables do not occur in end-user queries. They are introduced by the optimizer to help matching queries to materializations, and used only during the planning process.

When a materialization is defined, if it involves a join, it is converted to a query on top of a star table. Queries that are candidates to map onto the materialization are mapped onto the same star table.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	StarTable.StarTableScan Relational expression that scans a StarTable.

Field Summary

Fields

Modifier and Type	Field and Description
ImmutableIntList	fieldCounts Number of fields in each table's row type.
Lattice	lattice
com.google.common.collect.ImmutableList<Table>	tables

Method Summary

Methods

Modifier and Type	Method and Description
StarTable	add(Table table)
int	columnOffset(Table table) Returns the column offset of the first column of table in this star table's output row type.
Schema.TableType	getJdbcTableType() Type of table.
RelDataType	getRowType(RelDataTypeFactory typeFactory) Returns this table's row type.
static StarTable	of(Lattice lattice, List<Table> tables) Creates a StarTable and registers it in a schema.
RelNode	toRel(RelOptTable.ToRelContext context, RelOptTable table) Converts this table into a relational expression.

Methods inherited from class org.apache.calcite.schema.impl.AbstractTable

getStatistic

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.calcite.schema.Table

getStatistic

Field Detail

lattice

public final Lattice lattice

tables

public final com.google.common.collect.ImmutableList<Table> tables

fieldCounts

public ImmutableIntList fieldCounts

Number of fields in each table's row type.

Method Detail

of

public static StarTable of(Lattice lattice,
           List<Table> tables)

Creates a StarTable and registers it in a schema.

getJdbcTableType

public Schema.TableType getJdbcTableType()

Description copied from interface: Table

Type of table.

Specified by:

getJdbcTableType in interface Table

Overrides:

getJdbcTableType in class AbstractTable

getRowType

public RelDataType getRowType(RelDataTypeFactory typeFactory)

Description copied from interface: Table

Returns this table's row type.

This is a struct type whose fields describe the names and types of the columns in this table.

The implementer must use the type factory provided. This ensures that the type is converted into a canonical form; other equal types in the same query will use the same object.

Specified by:

getRowType in interface Table

Parameters:

typeFactory - Type factory with which to create the type

Returns:

Row type

toRel

public RelNode toRel(RelOptTable.ToRelContext context,
            RelOptTable table)

Description copied from interface: TranslatableTable

Converts this table into a relational expression.

Specified by:

toRel in interface TranslatableTable

add

public StarTable add(Table table)

columnOffset

public int columnOffset(Table table)

Returns the column offset of the first column of table in this star table's output row type.

Parameters:

table - Table

Returns:

Column offset

Throws:

IllegalArgumentException - if table is not in this star