Package org.apache.calcite.rel.logical

Class LogicalTableScan

java.lang.Object

org.apache.calcite.rel.AbstractRelNode

org.apache.calcite.rel.core.TableScan

org.apache.calcite.rel.logical.LogicalTableScan

All Implemented Interfaces:

Cloneable, RelOptNode, Hintable, RelNode

public final class LogicalTableScan
extends TableScan

A LogicalTableScan reads all the rows from a RelOptTable.

If the table is a net.sf.saffron.ext.JdbcTable, then this is literally possible. But for other kinds of tables, there may be many ways to read the data from the table. For some kinds of table, it may not even be possible to read all of the rows unless some narrowing constraint is applied.

In the example of the net.sf.saffron.ext.ReflectSchema schema,

select from fields

cannot be implemented, but

select from fields as f
 where f.getClass().getName().equals("java.lang.String")

can. It is the optimizer's responsibility to find these ways, by applying transformation rules.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.calcite.rel.RelNode

RelNode.Context

Field Summary

Fields inherited from class org.apache.calcite.rel.core.TableScan

hints, table

Fields inherited from class org.apache.calcite.rel.AbstractRelNode

digest, id, rowType, traitSet

Constructor Summary

Constructors

Constructor	Description
LogicalTableScan(RelOptCluster cluster, RelOptTable table)	Deprecated.
LogicalTableScan(RelOptCluster cluster, RelTraitSet traitSet, List<RelHint> hints, RelOptTable table)	Creates a LogicalTableScan.
LogicalTableScan(RelOptCluster cluster, RelTraitSet traitSet, RelOptTable table)	Deprecated.
LogicalTableScan(RelInput input)	Creates a LogicalTableScan by parsing serialized output.

Method Summary

Modifier and Type	Method	Description
RelNode	copy(RelTraitSet traitSet, List<RelNode> inputs)	Creates a copy of this relational expression, perhaps changing traits and inputs.
static LogicalTableScan	create(RelOptCluster cluster, RelOptTable relOptTable, List<RelHint> hints)	Creates a LogicalTableScan.
RelNode	withHints(List<RelHint> hintList)	Returns a new relational expression with the specified hints hintList.

Methods inherited from class org.apache.calcite.rel.core.TableScan

accept, computeSelfCost, deriveRowType, estimateRowCount, explainTerms, getHints, getTable, identity, identity, project

Methods inherited from class org.apache.calcite.rel.AbstractRelNode

accept, childrenAccept, collectVariablesSet, collectVariablesUsed, deepEquals, deepHashCode, equals, explain, getCluster, getConvention, getCorrelVariable, getDescription, getDigest, getExpectedInputRowType, getId, getInput, getInputs, getRelDigest, getRelTypeName, getRowType, getTraitSet, getVariablesSet, hashCode, isEnforcer, isValid, metadata, onRegister, recomputeDigest, register, replaceInput, sole, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.calcite.rel.hint.Hintable

attachHints

Methods inherited from interface org.apache.calcite.rel.RelNode

explain, fieldIsNullable, stripped

Constructor Details

LogicalTableScan

public LogicalTableScan(RelOptCluster cluster,
 RelTraitSet traitSet,
 List<RelHint> hints,
 RelOptTable table)

Creates a LogicalTableScan.

Use create(org.apache.calcite.plan.RelOptCluster, org.apache.calcite.plan.RelOptTable, java.util.List<org.apache.calcite.rel.hint.RelHint>) unless you know what you're doing.

LogicalTableScan

@Deprecated
public LogicalTableScan(RelOptCluster cluster,
 RelTraitSet traitSet,
 RelOptTable table)

Deprecated.

LogicalTableScan

@Deprecated
public LogicalTableScan(RelOptCluster cluster,
 RelOptTable table)

Deprecated.

LogicalTableScan

public LogicalTableScan(RelInput input)

Creates a LogicalTableScan by parsing serialized output.

Method Details

copy

public RelNode copy(RelTraitSet traitSet,
 List<RelNode> inputs)

Description copied from interface: RelNode

Creates a copy of this relational expression, perhaps changing traits and inputs.

Sub-classes with other important attributes are encouraged to create variants of this method with more parameters.

Specified by:

copy in interface RelNode

Overrides:

copy in class AbstractRelNode

Parameters:

traitSet - Trait set

inputs - Inputs

Returns:

Copy of this relational expression, substituting traits and inputs

create

public static LogicalTableScan create(RelOptCluster cluster,
 RelOptTable relOptTable,
 List<RelHint> hints)

Creates a LogicalTableScan.

Parameters:

cluster - Cluster

relOptTable - Table

hints - The hints

withHints

public RelNode withHints(List<RelHint> hintList)

Description copied from interface: Hintable

Returns a new relational expression with the specified hints hintList.

This method should be overridden by every logical node that supports hint. It is only for internal use during decorrelation.

Sub-class should return a new copy of the relational expression.

The default implementation returns the relational expression directly only because not every kind of relational expression supports hints.

Returns:

Relational expression with set up hints