How can I duplicate an array to another object?

Question

This seems fairly straightforward.

@new_email.distributions = @email.distributions.dup

After this is performed, both share identical distributions.

However, once the new object "saves". The old one loses all of its distributions.

Why is that?

FYI:

Distributions belongs_to :email. Email has_many :distributions

score 2 · Accepted Answer · answered Oct 26 '11 at 18:16

The way you model this causes the problem!

Each Distribution can only belong to just one email ... that email_id attribute is already set, and a Distribution can not belong to two emails! (there is only one email_id attribute in a Distribution).

You should use a "many-to-many" or "has-many-through" relation to model the association between your two models, and a join table between them, so you can store how distributions belong to more than just one email.

Brilliant! Didn't think of the obvious! Thanks so much!! – Trip Oct 26 '11 at 18:20 — Trip, Oct 26 '11 at 18:20

score 1 · Answer 2 · answered Oct 26 '11 at 18:22

1

Try using cloneinstead of dup.

answered Oct 26 '11 at 18:22

davidb

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score 0 · Answer 3 · answered Oct 26 '11 at 18:13

0

Because you using same object, try: some_other_var = @email.distributions.dup if I understood you correctly

answered Oct 26 '11 at 18:13

It's a different object. `@email = Email.find(params[:id]) @new_email = @email.clone @new_email.distributions = @email.distributions.dup` – Trip Oct 26 '11 at 18:19

How can I duplicate an array to another object?

3 Answers3