On 15 Jun 2011, at 17:22, Colin Law wrote:
This whole method runs into a lot of issues. What about has_many
objects,
they won't update with new id either. Is there not a method to have
rails
add or update based on id in a new object? Is this not how I should
be
working with distributed objects?
Have you tried using a before_create filter to force the id to the
appropriate value? I have not done this myself but I seem to remember
the technique being suggested.
Colin
On Wed, Jun 15, 2011 at 10:47 AM, Justin Stanczak
<[email protected]>
wrote:
To narrow down the issue I'm having, I can update an object that
exists.
Like so:
stu = Student.find('8edcfd63-801c-4ad3-b811-a6bdc440810e')
#### This will update the obj, but leave the id unchanged
stu.update_attributes!(JSON.parse(json_string))
But this will not work:
### Will not find this id
stu = Student.find('c6a4673e-90bd-4793-a62f-2e2fbdb857f6')
stu = Student.new
### ID will be nil after this update
stu.update_attributes!(JSON.parse(json_string))
### a forced save false will create a new id, not the one assigned
by json
I would think I'm just missing something simple, or how would a
distributed system work in Rails/Ruby?
Tinkering with what Rails consideres a "do-not-touch" value always
gets you into trouble. Mass assignment for ids is out of the question,
as far as I know so is setting the field individually through self.id=
It's with good reason too, the chance you'll screw up referential
integrity is too big.
There probably is some obscure way to set the id, but instead I would
just slap myself on the head and wonder: why the hell did I ever come
up with the idea of making that field the primary key instead of
letting Rails handle it and store that external JSON ID in some field
I can actually change :-)
BTW, what do you mean with a "distributed system"? If you're using a
distributed database, the database will take care of the ID
assignment. My impression is that you have an external application
that you access through a JSON API and you want to search the ID field
from the other application in your Rails application. That would be so
easy if you just let Rails handle it's primary key thing (creating its
own autoincrement ids), make a new field called
"my_fancy_dandy_external_api_id", index it and store the value of the
external app there. You can then fiddle with it all you want, Rails
won't care.
Best regards
Peter De Berdt
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