# Change model definition using scaffold **URL:** \ **Category:** Rails\ **Created:** [August 11, 2008, 12:42am UTC](https://www.ruby-forum.com/t/change-model-definition-using-scaffold/145505 "2008-08-11T00:42:38Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![Gromski](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/d26b3c/32.png) [@Gromski](https://www.ruby-forum.com/u/Gromski)\ **Post date:** [August 11, 2008, 12:42am UTC](https://www.ruby-forum.com/t/change-model-definition-using-scaffold/145505/1 "2008-08-11T00:42:38Z")
Hi all Apologies if this a trivially newb question but I’m new to rails (and frameworks in general) but is there a way to change the model definition using the scaffold, i.e. is it possible to update the model, views etc if I decide I need to add field d to fields a, b and c that I already created using script/generate scaffold…? At the moment I’m having to delete the generated code, rollback the DB migration ad generate it from scratch again - I’m sure there must be an easier/faster way. Cheers Mark ---
**Author:** ![Gromski](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/d26b3c/32.png) [@Gromski](https://www.ruby-forum.com/u/Gromski)\ **Post date:** [August 11, 2008, 12:46am UTC](https://www.ruby-forum.com/t/change-model-definition-using-scaffold/145505/2 "2008-08-11T00:46:09Z")
I understood the question’s answer seems to be: yes, you can edit the files themselves to reflect the changes you made to the model. If you added a new field x to the model, then you can change the files like \_form.html.erb to have the x field in it. On Mon, Aug 11, 2008 at 5:28 AM, Gromski [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > migration ad generate it from scratch again - I’m sure there must be > an easier/faster way. > > Cheers > > Mark – Ramon T. ---
**Author:** ![Gromski](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/d26b3c/32.png) [@Gromski](https://www.ruby-forum.com/u/Gromski)\ **Post date:** [August 13, 2008, 1:51am UTC](https://www.ruby-forum.com/t/change-model-definition-using-scaffold/145505/3 "2008-08-13T01:51:06Z")
Hi Ramon Not quite. I understand that the files can be edited ‘manually’ but I was wondering if there was a short hand using the scaffold so that I wouldn’t have to, e.g. I re-run script/generate with a different param to add a field to all of the relevant files… Cheers M On Aug 10, 11:45 pm, “Ramon Miguel M. Tayag” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) ---
**Author:** ![Gromski](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/d26b3c/32.png) [@Gromski](https://www.ruby-forum.com/u/Gromski)\ **Post date:** [August 13, 2008, 3:52am UTC](https://www.ruby-forum.com/t/change-model-definition-using-scaffold/145505/4 "2008-08-13T03:52:49Z")
On Aug 12, 6:50 pm, Gromski [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Hi Ramon > > Not quite. I understand that the files can be edited ‘manually’ but I > was wondering if there was a short hand using the scaffold so that I > wouldn’t have to, e.g. I re-run script/generate with a different param > to add a field to all of the relevant files… No, but you could: 1. Revert your migration with rake db:migrate:rollback (to go back one version; or use VERSION= explicitly) 2. script/destroy scaffold ModelName Then you can script/generate your scaffold again. But that’s a lot of work… easier to just manually update a few files. If you first refactor your new and edit forms out into a partial, you’ll save yourself some editing. Jeff REST with Rails Saturday, Oct 4, 2008 Austin, Texas [http://www.purpleworkshops.com/workshops/rest-and-web-services](http://www.purpleworkshops.com/workshops/rest-and-web-services) ---
**Author:** ![Gromski](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/d26b3c/32.png) [@Gromski](https://www.ruby-forum.com/u/Gromski)\ **Post date:** [August 13, 2008, 4:50am UTC](https://www.ruby-forum.com/t/change-model-definition-using-scaffold/145505/5 "2008-08-13T04:50:42Z")
Hi – On Sun, 10 Aug 2008, Gromski wrote: > migration ad generate it from scratch again - I’m sure there must be > an easier/faster way. In most cases if you want to modify an existing schema you would create a new migration file: script/generate migration add\_email\_column\_to\_user and then put what you need in the newly-created file and then run “rake db:migrate”. If you’re at the very beginning of a project, and decide you want to change something, you might migrate backwards and start again. Once the project is underway, though, migrating backwards ends up being more confusing than it’s worth in almost every case. As for the scaffolding, I wouldn’t recommend using it as the basis for a real application, except in cases where what it produces is exactly what you want. If you find yourself developing an app by starting with the scaffolding and making lots of changes (or wondering whether what you’re doing is OK because it deviates from the scaffolding), it’s a sign that you should abandon the scaffolding and just develop the app. Or you can skip that process and just abandon the scaffolding from the start 🙂 David – Rails training from David A. Black and Ruby Power and Light: - Advancing With Rails August 18-21 Edison, NJ - Co-taught by D.A. Black and Erik Kastner See [http://www.rubypal.com](http://www.rubypal.com) for details and updates!