# How to do save\_or\_update with ActiveRecords? **URL:** \ **Category:** Rails\ **Created:** [October 7, 2009, 12:47am UTC](https://www.ruby-forum.com/t/how-to-do-save-or-update-with-activerecords/176845 "2009-10-07T00:47:55Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Bjoern](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/46a35a/32.png) [@Bjoern](https://www.ruby-forum.com/u/Bjoern)\ **Post date:** [October 7, 2009, 12:47am UTC](https://www.ruby-forum.com/t/how-to-do-save-or-update-with-activerecords/176845/1 "2009-10-07T00:47:55Z")
Hi, I am trying to save return values from the Twitter API, so for example I have created a model for DirectMessages and Users. A direct message from Twitter contains a sender and recipient as nested hashes. I want to save these objects using the id from Twitter, too. I convert the hash to models like this: def convert\_direct\_message\_hash\_to\_model(dm) dm[“sender”] = User.new(dm[“sender”]){|sender| sender.id = dm [“sender”][“id”]} dm[“recipient”] = User.new(dm[“recipient”]) {|recipient| recipient.id = dm[“recipient”][“id”]} DirectMessage.new(dm) {|r| r.id = dm[“id”]} end then, if I try dm.save! with a self-sent message (so recipient = sender), I get an SQL error, because user id should be unique. It seems in this case ActiveRecord attempts to save the objects with an INSERT statement. Is there a way to make it update the record if the object already exists in the db, and otherwise create it? Also other comments to my approach are welcome, as I am fairly new to Rails. Thanks! Björn I get the error ---
**Author:** ![Bjoern](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/46a35a/32.png) [@Bjoern](https://www.ruby-forum.com/u/Bjoern)\ **Post date:** [October 7, 2009, 12:56am UTC](https://www.ruby-forum.com/t/how-to-do-save-or-update-with-activerecords/176845/2 "2009-10-07T00:56:42Z")
On Oct 6, 11:46 pm, Bjoern [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > then, if I try dm.save! with a self-sent message (so recipient = > sender), I get an SQL error, because user id should be unique. It > seems in this case ActiveRecord attempts to save the objects with an > INSERT statement. > > Is there a way to make it update the record if the object already > exists in the db, and otherwise create it? If that’s what you want then you should attempt to load the appropriate object first, create a new one if you can’t find one and then save (see also the dynamic finders - > **[ActiveRecord::Base](https://api.rubyonrails.org/classes/ActiveRecord/Base.html)** > > Active Record Active Record objects don't specify their attributes directly, but rather infer them from the table definition with which they're linked. ) Fred ---
**Author:** ![Bjoern](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/46a35a/32.png) [@Bjoern](https://www.ruby-forum.com/u/Bjoern)\ **Post date:** [October 7, 2009, 2:49am UTC](https://www.ruby-forum.com/t/how-to-do-save-or-update-with-activerecords/176845/3 "2009-10-07T02:49:04Z")
> > Is there a way to make it update the record if the object already > > exists in the db, and otherwise create it? > > If that’s what you want then you should attempt to load the > appropriate object first, create a new one if you can’t find one and > then save (see also the dynamic finders -[ActiveRecord::Base](http://api.rubyonrails.org/classes/ActiveRecord/Base.html) > ) Difficult, since the association seems to be saved automatically. I guess I have to switch that off somehow, then. No other way available? ---
**Author:** ![Bjoern](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/46a35a/32.png) [@Bjoern](https://www.ruby-forum.com/u/Bjoern)\ **Post date:** [October 7, 2009, 11:24am UTC](https://www.ruby-forum.com/t/how-to-do-save-or-update-with-activerecords/176845/4 "2009-10-07T11:24:14Z")
> I’m not quite sure what you’re saying. Instead of doing User.new, try > to find an appropriate User record first. I’d like to avoid that, to keep the part of the code clean from database access. I create a DirectMessage with two associated Users and then only call DirectMessage.save I suppose I could check all the Users before doing the save, but it would create a lot of clutter (compared to one line of executing save). I was hoping there would be a more elegant way. The API docs for save sound as if they would create or update, so maybe the question is how do they decide what is new and what needs updating. ---
**Author:** ![Bjoern](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/46a35a/32.png) [@Bjoern](https://www.ruby-forum.com/u/Bjoern)\ **Post date:** [October 7, 2009, 10:03am UTC](https://www.ruby-forum.com/t/how-to-do-save-or-update-with-activerecords/176845/5 "2009-10-07T10:03:27Z")
On Oct 7, 1:47 am, Bjoern [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > guess I have to switch that off somehow, then. No other way available? > I’m not quite sure what you’re saying. Instead of doing User.new, try > to find an appropriate User record first. Fred ---
**Author:** ![Bjoern](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/46a35a/32.png) [@Bjoern](https://www.ruby-forum.com/u/Bjoern)\ **Post date:** [October 7, 2009, 3:44pm UTC](https://www.ruby-forum.com/t/how-to-do-save-or-update-with-activerecords/176845/6 "2009-10-07T15:44:10Z")
On Oct 7, 11:52 am, Frederick C. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > If you do User.new you will always get a new object that AR will then > try to insert. Any other options? > Sounds like you would also get an error whenever you handle a message > to / from a user you have already handled a message from. True - so far I only tested it from unit tests, so I guess there was nothing else in the db. ---
**Author:** ![Bjoern](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/46a35a/32.png) [@Bjoern](https://www.ruby-forum.com/u/Bjoern)\ **Post date:** [October 7, 2009, 11:53am UTC](https://www.ruby-forum.com/t/how-to-do-save-or-update-with-activerecords/176845/7 "2009-10-07T11:53:31Z")
On Oct 7, 10:22 am, Bjoern [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > The API docs for save sound as if they would create or update, so > maybe the question is how do they decide what is new and what needs > updating. If you do User.new you will always get a new object that AR will then try to insert. Sounds like you would also get an error whenever you handle a message to / from a user you have already handled a message from. Fred ---
**Author:** ![Bjoern](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/46a35a/32.png) [@Bjoern](https://www.ruby-forum.com/u/Bjoern)\ **Post date:** [October 8, 2009, 10:03am UTC](https://www.ruby-forum.com/t/how-to-do-save-or-update-with-activerecords/176845/8 "2009-10-08T10:03:01Z")
On Oct 7, 2:42 pm, Bjoern [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > On Oct 7, 11:52 am, Frederick C. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) > wrote: > > > If you do User.new you will always get a new object that AR will then > > try to insert. > > Any other options? I think you just need to bite the bullet and find the record first. having a neat one liner is one thing but only if it actually works. You could hack around and fool activerecord into thinking the record isn’t new even though you’ve just called User.new but you’d probably just be storing up trouble for later and increasing the chances that your code breaks with a later version of rails. Fred