Has_many relation - NoMethodError

Rails
1

Hi

I have following tables:
Ressort
-name

Worker
-name
-ressort_id

then i defined that
Worker
belongs_to :ressort
and
Ressort
has_many: workers

Then I did rake db:migrate
And now I try to show all workers belongig to a ressort from console:
Ressort.find(1).workers
but get: NoMethodError: undefined method `workers’ for #<Ressort:
0x2a7cc98>

Is it because i have to create new worker and ressort entries first
now, or is my console request wrong?

BR
rogi

2

On 20 February 2011 12:33, rogi [email protected] wrote:

Ressort
has_many: workers

typo:
has_many :workers

…move the colon, and see what happens.

3

On 20 February 2011 12:47, rogi [email protected] wrote:

Nothing, I only had the typo here.
So, still facing the problem!

Does it work the other way around? can you call “Worker.first.ressort”?

4

Nothing, I only had the typo here.
So, still facing the problem!

class Ressort < ActiveRecord::Base
has_many :workers
end

5

No:

ActiveRecord::StatementInvalid: SQLite3::SQLException: no such column:
ressorts.worker_id: SELECT “ressorts”.* FROM “ressorts” WHERE
(“ressorts”.worker_id = 1) LIMIT 1

irb(main):037:0> Ressort
=> Ressort(id: integer, name: string, description: text, created_at:
datetime, updated_at: datetime)

6

This is weird. Could you paste your migration files and schema. Also,
did
you override the find method
for Worker class?

On Sun, Feb 20, 2011 at 9:23 PM, rogi [email protected]
wrote:

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7

irb(main):038:0> Ressort.find(1).workers
NoMethodError: undefined method `workers’ for #Ressort:0x3215328

irb(main):039:0> Worker.first.ressort
ActiveRecord::StatementInvalid: SQLite3::SQLException: no such column:
ressorts.worker_id: SELECT “ressorts”.* FROM “re
ssorts” WHERE (“ressorts”.worker_id = 1) LIMIT 1

=> Worker(id: integer, first_name: string, last_name: string,
created_at: datetime, updated_at: datetime, ressort_id: in
teger)

class AddRessortIdToWorkers < ActiveRecord::Migration
def self.up
add_column :workers, :ressort_id, :integer
end

def self.down
remove_column :workers, :ressort_id
end
end

class CreateRessorts < ActiveRecord::Migration
def self.up
create_table :ressorts do |t|
t.string :name
t.text :description

  t.timestamps
end

end

def self.down
drop_table :ressorts
end
end

8

On 20 February 2011 13:23, rogi [email protected] wrote:

No:

ActiveRecord::StatementInvalid: SQLite3::SQLException: no such column:
ressorts.worker_id: SELECT “ressorts”.* FROM “ressorts” WHERE
(“ressorts”.worker_id = 1) LIMIT 1

What command did you type to get this return value? It’s certainly
weird if you asked for “Worker.first”… (or Worker.all.first)

irb(main):037:0> Ressort
=> Ressort(id: integer, name: string, description: text, created_at:
datetime, updated_at: datetime)

…And what if you display “Worker”?

I think your migrations would help too… I really don’t think you’ve
quite got all the structure in place yet.

9

On 20 February 2011 16:59, rogi [email protected] wrote:

irb(main):038:0> Ressort.find(1).workers
NoMethodError: undefined method `workers’ for #Ressort:0x3215328

irb(main):039:0> Worker.first.ressort
ActiveRecord::StatementInvalid: SQLite3::SQLException: no such column:
ressorts.worker_id: SELECT “ressorts”.* FROM “re
ssorts” WHERE (“ressorts”.worker_id = 1) LIMIT 1

Can you paste the contents of ressort.rb and worker.rb? Do not
re-type them, copy and paste here please.
Also db/schema.rb

Colin

10

class Worker < ActiveRecord::Base
has_many :trainings
has_many :courses, :through => :trainings
belongs_to :ressort

def firstname_and_name
first_name+" "+last_name
end
end

class Ressort < ActiveRecord::Base
has_many :workers
end

class Course < ActiveRecord::Base
has_many :trainings
has_many :workers, :through => :trainings
end

11

could you confirm if the error still exists if you drop your db and
remigrate?

On Mon, Feb 21, 2011 at 5:30 PM, rogi [email protected]
wrote:

ressorts.worker_id: SELECT “ressorts”.* FROM "re

def self.up
create_table :ressorts do |t|
end

quite got all the structure in place yet.

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12

On 21 February 2011 09:30, rogi [email protected] wrote:

class Ressort < ActiveRecord::Base
has_many :workers
end

class Course < ActiveRecord::Base
has_many :trainings
has_many :workers, :through => :trainings
end

Please don’t top post, it makes it difficult to follow the thread.
Insert your reply at appropriate point in previous message. Thanks.

This really makes no sense to me. Is it possible that you have some
old files (backup files for example) in the app/model folder that may
be confusing rails? Have a look and remove anything extra there. Are
you absolutely sure you are looking at the right files? I know it
seems a stupid question but I remember once I had made a complete copy
of an application as a temporary backup and was editing the files in
one folder and running the server in the other. It took me a little
time to work out why nothing I changed seemed to make any difference
:slight_smile:

Colin

13

On 21 February 2011 10:50, Colin L. [email protected] wrote:

This really makes no sense to me.

+1
Everything looks good… nothing is jumping out at me - but the error
messages you’re getting don’t tie with what code/migrations you have.

Have a look and remove anything extra there. Are
you absolutely sure you are looking at the right files?

It could be worth just moving up one folder and typing “rails
project2” and starting again - you can copy the migrations and model
files over and check things one step at a time.

14

I tried following tutorial
http://biodegradablegeek.com/2007/12/understanding-basic-database-relationships-in-rails/
and also got the problem again:
irb(main):019:0> tune.genre = Genre.find_by_name(‘Blues Rock’)
NoMethodError: undefined method `genre=’ for #Song:0x3d08228

So maybe i have a general problem …

15

How can I drop and remigrate?

16

On 21 Feb., 11:31, Jim Ruther N. [email protected] wrote:

could you confirm if the error still exists if you drop your db and
remigrate?

On 24 February 2011 13:31, rogi [email protected] wrote:

How can I drop and remigrate?

one alternative:

rake db:migrate VERSION=0
rake db:migrate

17

In the same boat here. Did you ever resolve this?

Dan

18

And tadda… for me it was reloading the console. I updated the
relations
but didn’t reload the console… D’oh!