[development] correct way to update/insert a value in a table

mark burdett mfburdett at gmail.com
Mon Mar 31 18:34:07 UTC 2008

I happened to notice last night that db_affected_rows() is the number of
matched rows in the WHERE clause, not the number of rows that were actually
changed.  So (maybe only in drupal) if the data is the same these count as
"affected" rows.

If you grep core for db_affected_rows you see that the logic is
  db_query("UPDATE {variable} SET value = '%s' WHERE name = '%s'",
  if (!db_affected_rows()) {
    @db_query("INSERT INTO {variable} (name, value) VALUES ('%s', '%s')",


On Mon, Mar 31, 2008 at 9:13 AM, Earnie Boyd <earnie at users.sourceforge.net>

> Quoting John Fiala <jcfiala at gmail.com>:
> > On Mon, Mar 31, 2008 at 6:43 AM, Lluís <enboig at gmail.com> wrote:
> >> I need to save a value inside a table; I think the best/fast way of
> >> doing so is:
> >>
> >
> > Personally I like to keep track internally if a row's been saved to
> > the db or not - but I've seen some folks try the UPDATE statement,
> > call db_affected_rows to see if any rows were changed, and if none
> > were, to do the insert.
> Doesn't work if data is the same; no rows will be updated and
> db_affected_rows will return 0.  The method the OP used is correct
> insert else update.
> Earnie -- http://for-my-kids.com/
> -- http://give-me-an-offer.com/
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