I cannot clear relation with rails 3

Rails
1

hi,

im trying to update a relation through has many, but i cannot figure out
how to do it, so i thought i can just delete all the relation and create
them again, but i get error on clear method?

c = Campaign.last
=> #<Campaign id: 5, name: “sortable”, description: “pokads”,
default_segment: nil, account_id: 4, promotion_created: true>

c.campaigns_segments
=> [#<CampaignsSegments segment_id: 1, campaign_id: 5, sortable: nil>,
#<CampaignsSegments segment_id: 5, campaign_id: 5, sortable: nil>]

c.campaigns_segments.clear
NoMethodError: undefined method in' for nil:NilClass from /Library/Ruby/Gems/1.8/gems/activesupport-3.0.0/lib/active_support/whiny_nil.rb:48:inmethod_missing’
from
/Library/Ruby/Gems/1.8/gems/activerecord-3.0.0/lib/active_record/associations/has_many_association.rb:79:in
delete_records' from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.0/lib/active_record/associations/association_collection.rb:222:indelete’
from
/Library/Ruby/Gems/1.8/gems/activerecord-3.0.0/lib/active_record/associations/association_collection.rb:527:in
remove_records' from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.0/lib/active_record/associations/association_collection.rb:158:intransaction’
from
/Library/Ruby/Gems/1.8/gems/activerecord-3.0.0/lib/active_record/connection_adapters/abstract/database_statements.rb:139:in
transaction' from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.0/lib/active_record/transactions.rb:204:intransaction’
from
/Library/Ruby/Gems/1.8/gems/activerecord-3.0.0/lib/active_record/associations/association_collection.rb:157:in
transaction' from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.0/lib/active_record/associations/association_collection.rb:524:inremove_records’
from
/Library/Ruby/Gems/1.8/gems/activerecord-3.0.0/lib/active_record/associations/association_collection.rb:221:in
delete' from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.0/lib/active_record/associations/association_collection.rb:167:indelete_all’
from
/Library/Ruby/Gems/1.8/gems/activerecord-3.0.0/lib/active_record/associations/association_collection.rb:248:in
`clear’
from (irb):50

Is this rails 3 error or what?

please help :slight_smile:

thanks…

2

Hope you figured this out six months ago, but I just spent a few minutes
on this issue and found the answer after finding this unanswered post.
It may not be your solution, but it solved my issue with this exact
error.

For simple mapping tables using the :has_many relationship, the mapping
table needs to have an autoincrementing primary key, ‘id’. If you
create the table with :id => false, then you’re going to have this
problem once you try to start deleting from this table (you can insert
and read from it fine).

This is unlike relationships with the :has_and_belong_to_many, which
mapping tables do not require (and in fact can not have, I don’t think)
a PK ‘id’ field.

Jamal S. wrote in post #957804:

hi,

im trying to update a relation through has many, but i cannot figure out
how to do it, so i thought i can just delete all the relation and create
them again, but i get error on clear method?

c = Campaign.last
=> #<Campaign id: 5, name: “sortable”, description: “pokads”,
default_segment: nil, account_id: 4, promotion_created: true>

c.campaigns_segments
=> [#<CampaignsSegments segment_id: 1, campaign_id: 5, sortable: nil>,
#<CampaignsSegments segment_id: 5, campaign_id: 5, sortable: nil>]

c.campaigns_segments.clear
NoMethodError: undefined method `in’ for nil:NilClass
from

Is this rails 3 error or what?

please help :slight_smile:

thanks…