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, 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.

Field Summary

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

table

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

digest, id, rowType, traitSet

Constructor Summary

Constructors

Constructor and Description
LogicalTableScan(RelInput input) Creates a LogicalTableScan by parsing serialized output.
LogicalTableScan(RelOptCluster cluster, RelOptTable table) Deprecated.
LogicalTableScan(RelOptCluster cluster, RelTraitSet traitSet, RelOptTable table) Creates a LogicalTableScan.

Method Summary

Methods

Modifier and Type	Method and 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) Creates a LogicalTableScan.

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

accept, computeSelfCost, deriveRowType, explainTerms, getCollationList, getRows, getTable, identity, identity, isKey, project

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

accept, childrenAccept, collectVariablesSet, collectVariablesUsed, computeDigest, explain, getChildExps, getCluster, getConvention, getCorrelVariable, getDescription, getDigest, getExpectedInputRowType, getId, getInput, getInputs, getQuery, getRelTypeName, getRowType, getTraitSet, getVariablesStopped, isDistinct, isValid, metadata, onRegister, recomputeDigest, register, replaceInput, sole, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

LogicalTableScan

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

Creates a LogicalTableScan.

Use create(org.apache.calcite.plan.RelOptCluster, org.apache.calcite.plan.RelOptTable) unless you know what you're doing.

LogicalTableScan

@Deprecated
public LogicalTableScan(RelOptCluster cluster,
                           RelOptTable table)

Deprecated.

LogicalTableScan

public LogicalTableScan(RelInput input)

Creates a LogicalTableScan by parsing serialized output.

Method Detail

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)

Creates a LogicalTableScan.

Parameters:

cluster - Cluster

relOptTable - Table