Ruby on Rails

On 5 July 2015 at 16:07, Padmahas Bn <padmahas@gmail.com> wrote:
> Hello Colin these are the results I got
>>
>> >Try
>> >Role.where(id: user.roleid).select("role_name")
>
>
> #<Role:0x000000061d80e8>
>
> An invalid value. As I stated in my question this is similar to <% rolename
> = Role.select("role_name").where(id: user.roleid) %> but "where" and
> "select" are inter changed. So same invalid value.

Sorry, should be
Role.where(id: user.roleid).select(:role_name)

Swapping the order of method calls completely changes the meaning.
Role.select().where() fails because Role.select returns an array, and
one cannot call where on an array.  Role.where() returns an
ActiveRecord::Relation, and it is valid to call select on that.

>
>
>>
>> >Or even better
>> >user.role.select("role_name")
>
>
> private method `select' called for nil:NilClass
> Wouldn't work in my case because, I think it requires an Association between
> user and role table. And there Must be a field on both tables named
> "role_name". Which doesn't exist

Not role_name, but there there should be a relation between the two.
If you have a field in user which maps to the id of a role then
conventionally this would be called role_id and you would specify
User belongs_to role
Role has_many users
Then you could do as I have suggested.

I think you could benefit from working right through a good tutorial
such as railstutorial.org (which is free to use online) which would
show you the basics of rails.

Colin

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