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
* and this function returns a value M, it indicates that the 
	 * current row is the first row in groups with 
	 * indexes (M, M+1, ..., N ).
	 * @return	The 1-based index of the outermost group in which 
	 * 			the current row is the first row;
	 * 			(N+1) if the current row is not at the start of any group;
	 */
	int getStartingGroupLevel( ) throws DataException
	{
		checkHasCurrentRow( );
		
		if ( cacheProvider.getCurrentIndex( ) == 0 )
			return 0;
		
		if ( groups.length == 0 )
			return 1;
		
		int childGroupIdx = cacheProvider.getCurrentIndex( );
		int currentGroupIdx = leafGroupIdx;
		int level;
		for ( level = groups.length - 1; level >= 0; level-- )
		{
			
			
			
			GroupInfo currentGroup = findGroup( level, currentGroupIdx );
			if ( childGroupIdx == currentGroup.firstChild )
			{