EntityResolver resolver = getDomain().getEntityResolver();
ObjEntity paintingEntity = resolver.lookupObjEntity(Painting.class);
ObjEntity galleryEntity = resolver.lookupObjEntity(Gallery.class);
ObjEntity artistExhibitEntity = resolver.lookupObjEntity(ArtistExhibit.class);
ObjEntity exhibitEntity = resolver.lookupObjEntity(Exhibit.class);
ObjRelationship paintingToArtistRel = (ObjRelationship) paintingEntity
.getRelationship("toArtist");
paintingEntity.removeRelationship("toArtist");
ObjRelationship galleryToPaintingRel = (ObjRelationship) galleryEntity