Does the SQL Standard mention trigger events on DDL (ALTER, CREATE, DROP)?
The SQL Spec currently only says this about Triggers,


  4.6.5.5 Triggers
  
  A trigger is an object associated with a single base table or a single viewed table. A trigger specifies a subject table, trigger event, a trigger action time, and one or more triggered actions.
  
  
  A trigger event specifies what action on the subject table shall cause the triggered actions. A trigger event is either INSERT, DELETE, or UPDATE.
  A trigger action time specifies whether the triggered action is to taken BEFORE, INSTEAD OF, or AFTER the trigger event.
  A triggered action is either an &lt;SQL procedure statement&gt; or BEGIN ATOMIC, followed by one or more &lt;SQL procedure statement&gt;s terminated with &lt;semicolon&gt;s, followed by END.
  


Without any further mention, I believe the spec does not currently address this functionality at all.



Formatting slightly modified from the spec. I turned it into a list. Spec used "Information technology — Database languages — SQL —
Part 1: Framework (SQL/Framework)"