Retrieves an unique id from a given sequence.
Use this function if for some reason you can't use a serial field. For example, MySQL has no ways of reading of the current value of a sequence. Or sometimes you just need a unique integer.
$existing_id: After a database import, it might be that the sequences table is behind, so by passing in the maximum existing id, it can be assured that we never issue the same id.
An integer number larger than any number returned by earlier calls and: also larger than the $existing_id if one was passed in.
includes/ database/ database.inc, line 1345
- Core systems for the database layer.
- Base Database API class.
abstract public function nextId($existing_id = 0);