Bug 131011 Support running query based on report document data
Data Engine should support running a query based on data set and expression data stored in a report document. This bugzilla entry serves as a repository for design docs and notes related to this feature.
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/impl/document/RDGroupUtil.java
{
	/*
	 * groups[level] is an ArrayList of GroupInfo objects at the specified level.
	 * Level is a 0-based group index, with 0 denoting the outermost group, etc.
	 * Example: 
	 * Row GroupKey1 	GroupKey2 	GroupKey3 	Column4 	Column5 
	 * 0: 	CHINA 		BEIJING 	2003 		Cola 		$100 
	 * 1: 	CHINA		BEIJING		2003		Pizza 		$320 
	 * 2: 	CHINA		BEIJING		2004 		Cola 		$402 
	 * 3: 	CHINA		SHANGHAI	2003		Cola		$553 
	 * 4:	CHINA		SHANGHAI	2003		Pizza		$223
	 * 5: 	CHINA 		SHANGHAI	2004		Cola		$226
	 * 6: 	USA 		CHICAGO		2004		Pizza		$133
	 * 7: 	USA			NEW YORK	2004		Cola		$339
	 * 8: 	USA 		NEW YORK	2004		Cola		$297
	 * 
	 * groups: (parent, child) 
	 * 		LEVEL 0 		LEVEL 1 		LEVEL 2
	 * ============================================