Can anybody tell me step by step how validate data on form?

Rails
1

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

2

hi there,

there’s a nice tutorial about validation somewhere on day 4 i think:

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

3

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.

4

Hi,
I already tried the steps mentioned in the
“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

-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