is there a way to manipulate the modeles visually?

Hi , is a tool wich let you modify,add your models,atributes,relations ship?
http://jsplumb.org/jquery/demo.html Maybe there is a project like
that. or maybe
is a good idea to implement, i want to make such thing with these
librarie http://jsplumb.org/jquery/demo.html
but i want to ask first if some one already do it or if the idea is
good to implement it