drupal insert or update DB record with only one function

Question

similar quest is here: Help with db query in drupal - if exists update else insert

But drupal_write_record() third argument is to determine update or insert. Maybe drupal has another function, who self determine insert or update by primary key? Or I should it to program my self?

Answer 1

Have a look at the db_merge() function, I think it has the features you're looking for.