Bug 195970 Two issues when evaluate a query inlcuding a subquery[07]
Description: Currently, when evaluating a query which includes a subquery, the query will be evaluated twice. The binding of query will pass to subquery twice. If user write a java script such as new Date() and i++. The result of query will be incorrect. Another issue: when write the report document, the binding of query will be written twice and the performance is not good to evalulate it twice.
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/impl/ExprManagerUtil.java
l.addAll( autoBindingExprMap.keySet( ) );
		for ( int i = 0; i < bindingExprs.size( ); i++ )
		{
			l.addAll( ( (GroupBindingColumn) bindingExprs.get( i ) ).getColumnNames( ) );
		}
		return l;
	}
	
	/**
	 * 
	 * @return
	 */
	private HashMap getGroupKeys( )
	{
		List bindingExprs = exprManager.getBindingExprs( );
		HashMap l = new HashMap( );
		for ( int i = 0; i < bindingExprs.size( ); i++ )
		{
			String key = ( (GroupBindingColumn) bindingExprs.get( i ) ).getGroupKey( );
			Integer groupLevel = new Integer( ( (GroupBindingColumn) bindingExprs.get( i ) ).getGroupLevel( ) );
			if ( key != null )
				l.put( groupLevel, key );
		}
		return l;
	}
	
	/**
	 *
	 */
	public static class Node