Ensuring both objects in a one-to-many association are not saved without the presence of the other

Rails
1

Hello.

I have an object which is related to a second object through has_many.
The second object (obviously) is related to the first through
belongs_to. I want to ensure that neither object is saved to the
database without the presence of the other. How can I do this?

Thanks.

Evan

2

Evan wrote:

Hello.

I have an object which is related to a second object through has_many.
The second object (obviously) is related to the first through
belongs_to. I want to ensure that neither object is saved to the
database without the presence of the other. How can I do this?

Thanks.

Evan

Use transaction

3

Even with transactions can I save the object containing the foreign
key without saving the primary object first? In other words, can I
save the object that requires the foreign key to be present if I don’t
have the foreign key because the primary object has not yet been
saved, thus generating an id for it?

4

I guess the question I was really getting at is how can I validate the
presence and association of both objects before they are saved? I feel
more confident when there is code in the model itself to ensure the
integrity of the data rather than depending on each programmer to
place every save in a transaction block.

5

Oh wait. I think I just got it. Start a transaction, save the primary
object thus getting the id, save the secondary object, end
transaction. Right?

6

http://api.rubyonrails.org/classes/ActiveRecord/Validations/ClassMethods.html#M001343