.hash in ActiveRecord

Question

I am encountering a function (?) that I do not fully understand in Rails and ActiveRecord.

I am building a basic website where the user (created with devise) can upload a document (the fields are: title and the attachment) Therefore, when the users goes to www.website.com/documents/new he is present with a simple_form that asks him to write a title and attache a PDF. Once confirmed, the document is saved in the database and linked to the user. Everything works fine.

My question is the following: when I run rails console and run Document.last.hash (or for any other stored document), I get back a numeric field back such as: 3130256425345013276

Can someone explain me what it is? Is it a hash function (like SHA-256 algorithm) to secure the encryption in the database? If yes, among all the hash functions, which is the one ActiveRecord is using?

Answer 1

Is it a hash function to secure the encryption in the database?

It is a hash function, but has nothing to do with encryption. It's used when you use objects as keys in hashes.