ActiveRecord::Relation error

Question

Error from Rails, does this make sense to you?

<%= @permission.inspect %> outputs: [#<Permission project_id: 3, role_id: 2, user_id: 13>]

<%= Role.find(@permission.role_id) %>

undefined method `role_id' for [#<Permission project_id: 3, role_id: 2, user_id: 13>]:ActiveRecord::Relation

This doesn't work either for some reason: @permission.role.name

Any Ideas? thanks

Swanand · Accepted Answer · 2010-10-11 07:17:18Z

3

@permissions is a collection (Array). Try @permissions.first.role_id

answered Oct 11, 2010 at 7:17

Swanand

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2 Comments

WozPoz Over a year ago

Thanks. but permission should never return more than one record. Is there a way to obtain the var in Rails to specifiy it's not a collection but a single record? Right now I have: @permission = Permission.where(["user_id = ? AND project_id = ?", @user.id, @project.id]) thanks

Swanand Over a year ago

Yes, in that case, as Shingara has said, @permission = Permission.where(["user_id = ? AND project_id = ?", @user.id, @project.id]).first. This will either return the permission object, or nil if no matching rows are found.

shingara · Accepted Answer · 2010-10-11 15:58:34Z

2

@permission is an Array so you need iterate on it

<% @permission.each do |perm| %>
  <%= Role.find(perm.role_id) %>
<% end %>

If you want only one @permission return :

@permission = Permission.where(["user_id = ? AND project_id = ?", @user.id, @project.id]).first

edited Oct 11, 2010 at 15:58

answered Oct 11, 2010 at 7:17

shingara

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4 Comments

WozPoz Over a year ago

Thanks. but permission should never return more than one record. Is there a way to obtain the var in Rails to specifiy it's not a collection but a single record? Right now I have: @permission = Permission.where(["user_id = ? AND project_id = ?", @user.id, @project.id]) thanks

shingara Over a year ago

use @permission = Permission.where(["user_id = ? AND project_id = ?", @user.id, @project.id]).first

WozPoz Over a year ago

Thanks... If there is only 1 matching result in the DB, will it return an array? Or is it always an array?

shingara Over a year ago

it's return nil or your object no anymore Array

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