How to get mysql_insert_id() for updates

[samona]

How do i get the Primary Key when I do an update.  When I do an Insert I use mysql_insert_id() to capture the primary key.  IS there a way to do it with Update?

[rhodesa]

No, with UPDATE, you are editing records, not adding ones. So no *new* IDs are generated. You need to know the ID of the record you want to update before doing the update.

[fenway]

How do i get the Primary Key when I do an update.  When I do an Insert I use mysql_insert_id() to capture the primary key.  IS there a way to do it with Update?

How did you know which one to update without the PK?