anchor.diff:  
   (defun get (model key &key (from-json *from-json*))
     "Lookup the object with primary key KEY (of type compatible with
  -Postgres type *KEY-TYPE*) in MODEL, a symbol.  If such an object exists
  -return a parse of the JSON string by the the function of one argument
  -designated by FROM-JSON (make it #'identity to return just the JSON
  -string proper).  If the object does not exist, return nil."
  +Postgres type KEY-TYPE in the model's parameters, in MODEL, a symbol.
  +If such an object exists return a parse of the JSON string by the the
  +function of one argument designated by FROM-JSON (make it #'identity
  +to return just the JSON string proper).  If the object does not exist,
  +return nil."
     (log:debu4 "Get object with key ~A from ~A" key model)
     (ensure-model-query model 'get$)
     (let ((jdoc (ensure-transaction-level (get read-committed-ro)
  
positive.code:     (mapcar from-json (get-all$ model))))
  
  (defun delete (model key)
    "Delete the object with primary key KEY (of type compatible with
  Postgres type *KEY-TYPE*).  Returns KEY on success, NIL if there was no
  such KEY found."
    (log:debu3 "Attempt delete of object with key ~A from ~A" key model)
    (ensure-model-query model 'insert-old$ 'delete$)
    (ensure-transaction-level (delete repeatable-read-rw)
  
negative.code:       (nth-value 0 (insert$ model key (funcall to-json object))))))
  
  (defun update (model key object &key (stash-key *stash-key*) (to-json *to-json*))
    "Update the current value of the object with primary key KEY, of
  type compatible with Postgres type KEY-TYPE in the model's parameters,
  in backend MODEL, a symbol, to be the JSON serialization of OBJECT.
  If STASH-KEY is non null we FUNCALL it with two arguments: the value
  of the key to be used for the DB insert and OBJECT.  It should return
  an object which will be used in the place of the original.  TO-JSON
  must be a function designator for a function of one argument to
  serialize lisp objects to JSON strings.  Returns KEY on success, NIL
  if there was no such KEY found."
    (log:debu3 "Attempt update of ~A in ~A" key model)
    (ensure-model-query model 'insert-old$ 'update$)
    (ensure-transaction-level (update repeatable-read-rw)
  