Rails: force specific id for new record (or change id of existing)

Question

Due to an error that deleted a user in our Rails app I'm trying to force another user record into the old records ID.

$ rails console
> User.find(2)
ActiveRecord::RecordNotFound: Couldn't find User with 'id'=2
> replacer = User.find(5)
=> #<User id: 5, created_at: [omitted for brevity ...] >
replacer.id = 2
=> 2
replacer.save
=> true
> User.find(2)
ActiveRecord::RecordNotFound: Couldn't find User with 'id'=2
> User.find(5)
ActiveRecord::RecordNotFound: Couldn't find User with 'id'=5
> replacer
=> #<User id: 2, created_at: [omitted for brevity ...] >
> replacer.valid?
=> true

What's going on here?

I did something like this before with AR. Not sure how to do this in the database… weird thing is record appears to have saved yet can't be found at id: 5 *or* id: 2. It's like it's lost in limbo… — Meltemi, Apr 23 '15 at 01:02

score 5 · Accepted Answer · answered Apr 23 '15 at 12:58

5

Your update statement is constructed using the id of the in memory object, which you have set to 2. You can't update a record that doesn't exist.

If you want to stay in active record land I think you can do: User.update(5, id: 2)

Failing that, you can definitely do it in SQL. UPDATE users SET id = 2 WHERE id = 5.

answered Apr 23 '15 at 12:58

Derek Prior

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Can this be done across tables too, for relationships? For example you have the same company entered twice in the db, there are also relationships to both and you'd need all relationships to one to refer the other so you can merge them. – unom Feb 06 '17 at 14:59

Rails: force specific id for new record (or change id of existing)

1 Answers1