net.sf.saffron.sql2rel
Class SqlToRelConverter.Blackboard

java.lang.Object
  |
  +--net.sf.saffron.sql2rel.SqlToRelConverter.Blackboard

Enclosing class:

SqlToRelConverter

private class SqlToRelConverter.Blackboard

extends Object

Workspace for translating an individual SELECT statement (or sub-SELECT).

Field Summary

private SaffronRel[]	inputs
private HashMap	mapSubqueryToExpr Maps IN and EXISTS sub-queries to the expressions which will be used to access them.
private SaffronRel	root
(package private) SqlValidator.Scope	scope Collection of SaffronRel objects which correspond to a SELECT statement.
private ArrayList	subqueries List of IN and EXISTS nodes inside this SELECT statement (but not inside sub-queries).

Constructor Summary

(package private)

SqlToRelConverter.Blackboard(SqlValidator.Scope scope) Creates a Blackboard

Method Summary

private ArrayList	flatten(SaffronRel[] rels)
private void	flatten(SaffronRel[] rels, ArrayList list)
(package private) RexNode	lookup(int offset, SaffronRel[] inputs, boolean isParent, String varName) Creates an expression with which to reference expression, whose offset in its from-list is offset.
(package private) RexNode	lookupExp(String name) Returns an expression with which to reference a from-list item.
RexNode	register(SaffronRel rel) Registers a relational expression
void	registerSubquery(SqlNode node)
(package private) void	setRoot(SaffronRel root)
(package private) void	setRoot(SaffronRel[] inputs)

Methods inherited from class java.lang.Object

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

Field Detail

scope

final SqlValidator.Scope scope

Collection of SaffronRel objects which correspond to a SELECT statement.

root

private SaffronRel root

inputs

private SaffronRel[] inputs

subqueries

private final ArrayList subqueries

List of IN and EXISTS nodes inside this SELECT statement (but not inside sub-queries).

mapSubqueryToExpr

private final HashMap mapSubqueryToExpr

Maps IN and EXISTS sub-queries to the expressions which will be used to access them.

Constructor Detail

SqlToRelConverter.Blackboard

SqlToRelConverter.Blackboard(SqlValidator.Scope scope)

Creates a Blackboard

Pre-condition:

scope != null

Method Detail

register

public RexNode register(SaffronRel rel)

Registers a relational expression

Parameters:

rel - Relational expression

Returns:

Expression with which to refer to the row (or partial row) coming from this relational expression's side of the join.

setRoot

void setRoot(SaffronRel root)

setRoot

void setRoot(SaffronRel[] inputs)

lookupExp

RexNode lookupExp(String name)

Returns an expression with which to reference a from-list item.

Parameters:

name - the alias of the from item

Returns:

a Variable or FieldAccess

lookup

RexNode lookup(int offset,
               SaffronRel[] inputs,
               boolean isParent,
               String varName)

Creates an expression with which to reference expression, whose offset in its from-list is offset.

flatten

private ArrayList flatten(SaffronRel[] rels)

flatten

private void flatten(SaffronRel[] rels,
                     ArrayList list)

registerSubquery

public void registerSubquery(SqlNode node)