Placeholders, are the way to go in mysql. In postgres (DBD::pg) you explicitly need to do something like:

my $sth = $dbh->prepare("INSERT INTO foo (blob) VALUES (?)");
$sth->bind_param(1, $blob_data, { pg_type => DBD::Pg::PG_BYTEA });
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This is a pain in the ass, I wish postgres would just let placeholders work with binary magically like mysql does.