ALTER CONSTRAINT <constraint-name> ---------+
      +---------------------------------------+
      +--+--+--> COMMENT IS +-> '<text-literal>' -+--+--+-->
         |  |               +------- / <----------+  |  |
         |  +--> constraint-attributes --------------+  |
         |  +--> RENAME TO <new-constraint-name> ----+  |
         +-------------------- <------------------------+

  constraint-attributes =

  -+-> DEFERRABLE -------------+------------------------------+-+->
   |                           +-> INITIALLY +-> IMMEDIATE --++ |
   |                                         +-> DEFERRED ---+  |
   +-> NOT DEFERRABLE ---------+-------------------------+------+
   |                           +-> INITIALLY IMMEDIATE --+      |
   +-> INITIALLY IMMEDIATE ----+-------------------+------------+
   |                           +-> DEFERRABLE -----+            |
   |                           +-> NOT DEFERRABLE -+            |
   +-> INITIALLY DEFERRED -----+-------------------+------------+
                               +-> DEFERRABLE -----+