PostgreSQL next value of the sequences?

Question

I am using PostgreSQL for my Codeigniter website. I am using grocery crud for add, edit and delete operations. While doing an edit or add, I want to rename an uploaded file

Answer 1

Even if this can somehow be done it is a terrible idea since it would be possible to get a sequence that then gets used by another record!

A much better idea is to save the record and then retrieve the sequence afterwards.