title: How to deny create tables without primary key in Firebird
body: <p>Is it possible to create (DDL) trigger in Firebird 2.5 which will deny create tables without primary key? </p>
  
  <p>I read this article <a href="https://firebirdsql.org/file/documentation/release_notes/html/en/3_0/rnfb30-psql-ddltriggers.html" rel="nofollow noreferrer">https://firebirdsql.org/file/documentation/release_notes/html/en/3_0/rnfb30-psql-ddltriggers.html</a> and google all over the internet, but didn't find any solution.</p>
  
  <p>My code looks like:</p>
  
  <pre><code>create trigger trg_no_pk_table
  before CREATE TABLE
  as
  begin
  
  if (rdb$get_context('DDL_TRIGGER', '??????') ???????) then
          exception e_table_without_pk;
  end
  </code></pre>
  
  <p>What do I need to wrote instead '????'?</p>