Sans nom

		  UPDATE _element 
		  SET 	 counters = 
		  	COALESCE 
			(
				counters || 
				(
					TG_RELNAME::text => 
					(
						SELECT (COALESCE ((counters->(TG_RELNAME::text))::int, 0) + 1)::text 
						FROM   _element
						WHERE  _element.id = NEW.id
					)
				), 
				(
					TG_RELNAME::text => 
					(
						SELECT (COALESCE ((counters->(TG_RELNAME::text))::int, 0) + 1)::text 
						FROM   _element
						WHERE  _element.id = NEW.id
					)
				)
			)		  
		  WHERE  _element.path @> NEW.path;