# Can anybody tell me step by step how validate data on form? **URL:** \ **Category:** Rails\ **Created:** [March 14, 2006, 8:13am UTC](https://www.ruby-forum.com/t/can-anybody-tell-me-step-by-step-how-validate-data-on-form/54788 "2006-03-14T08:13:23Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![tiwaripk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/7ab992/32.png) [@tiwaripk](https://www.ruby-forum.com/u/tiwaripk)\ **Post date:** [March 14, 2006, 8:13am UTC](https://www.ruby-forum.com/t/can-anybody-tell-me-step-by-step-how-validate-data-on-form/54788/1 "2006-03-14T08:13:23Z")
Hi, I am new to ROR. I have created a form with foru fields in ROR. Now its working fine for all CRUD operations. But I want to validate data on form for “validates\_presence\_of” validation. How to do this? I tried it by putting line “validates\_presence\_of :description” . But its not working. Its throws error like “undefined method `each’ for nil:NilClass” Also what is “:description” in the “validates\_presence\_of :description” ? Is it a database column name or name of the field (textbox) on my form that is responsible for holding value of description field? Please help me. Thanks in advaance. Prash ---
**Author:** ![tiwaripk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/7ab992/32.png) [@tiwaripk](https://www.ruby-forum.com/u/tiwaripk)\ **Post date:** [March 14, 2006, 8:57am UTC](https://www.ruby-forum.com/t/can-anybody-tell-me-step-by-step-how-validate-data-on-form/54788/2 "2006-03-14T08:57:58Z")
hi there, there’s a nice tutorial about validation somewhere on day 4 i think: [http://www.rails4days.pwp.blueyonder.co.uk/Rails4Days.pdf](http://www.rails4days.pwp.blueyonder.co.uk/Rails4Days.pdf) -david Prashant T. wrote: > Hi, > > I am new to ROR. I have created a form with foru fields in ROR. Now its > working fine for all CRUD operations. But I want to validate data on > form for “validates\_presence\_of” validation. How to do this? > I tried it by putting line “validates\_presence\_of :description” . But > its not working. Its throws error like “undefined method `each’ for > nil:NilClass” > Also what is “:description” in the “validates\_presence\_of :description” > ? Is it a database column name or name of the field (textbox) on my form > that is responsible for holding value of description field? > > Please help me. > > Thanks in advaance. > Prash ---
**Author:** ![tiwaripk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/7ab992/32.png) [@tiwaripk](https://www.ruby-forum.com/u/tiwaripk)\ **Post date:** [March 14, 2006, 1:09pm UTC](https://www.ruby-forum.com/t/can-anybody-tell-me-step-by-step-how-validate-data-on-form/54788/3 "2006-03-14T13:09:37Z")
With “validates\_presence\_of :description”, “description” refers to a field in your table. It goes in the model for one of your tables; the “description” field will be in that table. When you go to create or update a record in that table, the “description” field has to be non-null. The “undefined method ‘each’ for nil::NilClass” error is saying that you’re trying to do an “each” iteration on an object that has a nil value - you can’t do an ‘each’ on it because nil objects don’t have subcomponents. Check for a typo in your code somewhere; if that doesn’t help, use breakpoints to pause things at an appropriate spot so you can check the values of your variables. Regards Dave M. ---
**Author:** ![tiwaripk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/7ab992/32.png) [@tiwaripk](https://www.ruby-forum.com/u/tiwaripk)\ **Post date:** [March 14, 2006, 9:28am UTC](https://www.ruby-forum.com/t/can-anybody-tell-me-step-by-step-how-validate-data-on-form/54788/4 "2006-03-14T09:28:45Z")
Hi, I already tried the steps mentioned in the “[http://www.rails4days.pwp.blueyonder.co.uk/Rails4Days.pdf](http://www.rails4days.pwp.blueyonder.co.uk/Rails4Days.pdf)”. But not working. I m getting above error. Please help me. I am trying from last 2 days. Thanx in advance. Prash David Ang wrote: > hi there, > > there’s a nice tutorial about validation somewhere on day 4 i think: > > [http://www.rails4days.pwp.blueyonder.co.uk/Rails4Days.pdf](http://www.rails4days.pwp.blueyonder.co.uk/Rails4Days.pdf) > > -david > > Prashant T. wrote: > > > Hi, > > > > I am new to ROR. I have created a form with foru fields in ROR. Now its > > working fine for all CRUD operations. But I want to validate data on > > form for “validates\_presence\_of” validation. How to do this? > > I tried it by putting line “validates\_presence\_of :description” . But > > its not working. Its throws error like “undefined method `each’ for > > nil:NilClass” > > Also what is “:description” in the “validates\_presence\_of :description” > > ? Is it a database column name or name of the field (textbox) on my form > > that is responsible for holding value of description field? > > > > Please help me. > > > > Thanks in advaance. > > Prash