CREATE TRIGGER --> <trigger-name> ------+
  +---------------------------------------+
  +-+-----------------------------------+-+
    +-> STORED NAME IS <stored-name> ---+ |
  +------------------<--------------------+
  ++-> BEFORE -+-+-> INSERT --------------------------------+-+
   +-> AFTER --+ +-> DELETE --------------------------------+ |
                 +-> UPDATE --+--------------------------+--+ |
                              +--> OF -+> <column-name> ++    |
                                       +--- , <---------+     |
  +----------------------------<------------------------------+
  +-> ON <table-name> +-----------------------++-> triggered-action -+>
                      +-> referencing-clause -++----------<----------+

  referencing-clause =

  REFERENCING -++-> OLD AS --> <old-correlation-name> -++->
               |+-> NEW AS --> <new-correlation-name> -+|
               +------------------<---------------------+

  triggered-action =

  --+---------------------+-> ( -+> triggered-statement -+-> ) -+
    +-> WHEN (predicate) -+      +----------- , <--------+      |
                                 +----------- ; <--------+      |
     +---------------------------<------------------------------+
     +-+------------------------+------------------------------->
       +-> FOR EACH ROW --------+
       +-> FOR EACH STATEMENT --+

  triggered-statement =

  --+-> call-statement ---+-->
    +-> delete-statement -+
    +-> ERROR ------------+
    +-> insert-statement -+
    +-> signal-statement -+
    +-> trace-statement --+
    +-> update-statement -+