Places for placeholders

[0rir]

$!dbh.execute("SET log_min_messages TO $level");

$sth = $!dbh.execute( "SHOW $var-name" );

I expected DBIish via DBDish::Pg to accept ? placeholders in the above.
Only with the pause caused by my error, did I consider that SET might reasonably take two placeholders.

[rbt]

Right now everything goes through PQexecPrepared which is limited to CRUD type statements. We should have a fall-back mode for Pg which does parameter quoting/injecting and calls PQexec.