I have a custom field (true / false) which I want to update using a MySQL query. I want to turn the field on for all instances of a certain post type.
I can change existing values in the postmeta table, but if a post hasn't used the custom field yet there's no entry in the postmeta table for it.
I have a sneaking suspicion that I can't just add new rows to the postmeta table.
Does anyone know how to do this properly?