org.eigenbase.sql2rel
Class SqlToRelConverter.LookupContext

java.lang.Object
  org.eigenbase.sql2rel.SqlToRelConverter.LookupContext

Enclosing class:

SqlToRelConverter

private static class SqlToRelConverter.LookupContext
extends Object

Context to find a relational expression to a field offset.

Field Summary

private List<Pair<RelNode,Integer>>

relOffsetList

Constructor Summary

SqlToRelConverter.LookupContext(RelNode rel, int systemFieldCount)
Creates a LookupContext with a single input relational expression.

SqlToRelConverter.LookupContext(SqlToRelConverter.Blackboard bb, RelNode[] rels, int systemFieldCount)
Creates a LookupContext with multiple input relational expressions.

Method Summary

(package private) Pair<RelNode,Integer>

findRel(int offset) Returns the relational expression with a given offset, and the ordinal in the combined row of its first field.

Methods inherited from class java.lang.Object

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

Field Detail

relOffsetList

private final List<Pair<RelNode,Integer>> relOffsetList

Constructor Detail

SqlToRelConverter.LookupContext

SqlToRelConverter.LookupContext(RelNode rel,
                                int systemFieldCount)

Creates a LookupContext with a single input relational expression.

Parameters:

rel - Relational expression

systemFieldCount - Number of system fields

SqlToRelConverter.LookupContext

SqlToRelConverter.LookupContext(SqlToRelConverter.Blackboard bb,
                                RelNode[] rels,
                                int systemFieldCount)

Creates a LookupContext with multiple input relational expressions.

Parameters:

bb - Context for translating this subquery

rels - Relational expressions

systemFieldCount - Number of system fields

Method Detail

findRel

Pair<RelNode,Integer> findRel(int offset)

Returns the relational expression with a given offset, and the ordinal in the combined row of its first field.

For example, in Emp JOIN Dept, findRel(1) returns the relational expression for Dept and offset 6 (because Emp has 6 fields, therefore the first field of Dept is field 6.

Parameters:

offset - Offset of relational expression in FROM clause

Returns:

Relational expression and the ordinal of its first field