saffron.sql
Class AddProjectToQueryRule

java.lang.Object
  |
  +--saffron.opt.Rule
        |
        +--saffron.sql.AddProjectToQueryRule

class AddProjectToQueryRule

extends Rule

A AddProjectToQueryRule grafts a Project onto a JdbcQuery. This rule does not apply if the query already has a select list (other than the default, null, which means '*'). todo: Write a rule to fuse two Projects together.

Since:

Aug 7, 2002

Version:

$Id: //open/saffron/src/main/saffron/sql/AddProjectToQueryRule.java#3 $

Author:

jhyde

Field Summary

Fields inherited from class saffron.opt.Rule

description, planner

Constructor Summary

(package private)

AddProjectToQueryRule()

Method Summary

void	onMatch(RuleCall call) This method is called every time the rule matches.

Methods inherited from class saffron.opt.Rule

convert, getOutConvention, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

AddProjectToQueryRule

AddProjectToQueryRule()

Method Detail

onMatch

public void onMatch(RuleCall call)

Description copied from class: Rule

This method is called every time the rule matches. At the time that this method is called, call.rels holds the set of relational expressions which match the operands to the rule; call.rels[0] is the root expression.

Typically a rule would check that the nodes are valid matches, creates a new expression, then calls back RuleCall.transformTo(saffron.rel.Rel) to register the expression.

Specified by:

onMatch in class Rule