Ruby on Rails - Primary and Foreign key
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by Eef
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Published on 2010-05-10T10:26:42Z
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2010/05/10
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Hey,
I am creating a site in Ruby on Rails, I have two models a User
model and a Transaction
model.
These models both belong to an account so they both have a field called account_id
I am trying to setup a association between them like so:
class User < ActiveRecord::Base
belongs_to :account
has_many :transactions
end
class Transaction < ActiveRecord::Base
belongs_to :account
belongs_to :user
end
I am using these associations like so:
user = User.find(1)
transactions = user.transactions
At the moment the application is trying to find the transactions with the user_id
, here is the SQL it generates:
Mysql::Error: Unknown column 'transactions.user_id' in 'where clause': SELECT * FROM `transactions` WHERE (`transactions`.user_id = 1)
This is incorrect as I would like the find the transactions via the account_id
, I have tried setting the associations like so:
class User < ActiveRecord::Base
belongs_to :account
has_many :transactions, :primary_key => :account_id, :class_name => "Transaction"
end
class Transaction < ActiveRecord::Base
belongs_to :account
belongs_to :user, :foreign_key => :account_id, :class_name => "User"
end
This almost achieves what I am looking to do and generates the following SQL:
Mysql::Error: Unknown column 'transactions.user_id' in 'where clause': SELECT * FROM `transactions` WHERE (`transactions`.user_id = 104)
The number 104
is the correct account_id
but it is still trying to query the transaction table for a user_id
field. Could someone give me some advice on how I setup the associations to query the transaction table for the account_id
instead of the user_id
resulting in a SQL query like so:
SELECT * FROM `transactions` WHERE (`transactions`.account_id = 104)
Cheers
Eef
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