How to relate model with self value?

Rails
1

Hi,
I’m developing with ruby-1.9. 1 rails 3.0.0.
I want to relate ‘User’ model and ‘Payment’ model with condition which
has the same value as ‘user.testing’ in ‘payment.testing’

I did

Class User < ActiveRecord::Base
has_many payments, :conditions => [‘testing = ?’, self.testing]
end

This doesn’t work.
I tried also below, but doesn’t work too.
has_many payments, :conditions => [‘testing = ?’,
#{self.send(:testing)}]

Any ideas?

Regards.

2

You could just use a method instead…

class User < ActiveRecord::Base

has_many :payments

def testing_payments
payments.where(:testing => testing)
end

end

3

On 15 December 2010 17:01, Tim S. [email protected] wrote:

You could just use a method instead…

class User < ActiveRecord::Base

has_many :payments

def testing_payments
payments.where(:testing => testing)
end

That would be even better as a named scope.

Colin

4

On Dec 15, 2010, at 12:04 PM, Colin L. wrote:

That would be even better as a named scope.

Colin

Actually, it would be better if it worked:

class User < ActiveRecord::Base
has_many :payments

def testing_payments
payments.where(:testing => true) # testing is a local?
end
end

somebody = User.find(params[:id])

Then, you could say:
somebody.testing_payments

Or add a scope to Payment

class Payment < ActiveRecord::Base
belongs_to :user

scope :testing, where(:testing => true)
end

And you’d say:
somebody.payments.testing

Either would work. If testing is a instance method of User, then the
original suggestion might actually be “better.”

-Rob

Rob B.
[email protected] http://AgileConsultingLLC.com/
[email protected] http://GaslightSoftware.com/

5

On Wednesday, December 15, 2010 12:50:03 PM UTC-5, rob wrote:

ActiveRecord::Base belongs_to :user scope :testing, where(:testing => true)
end And you’d say: somebody.payments.testing Either would work. If testing
is a instance method of User, then the original suggestion might actually be
“better.” -Rob Rob B. [email protected]
http://AgileConsultingLLC.com/ [email protected]
http://GaslightSoftware.com/

The problem with this is that he doesn’t want to find Payments where
testing
= true, he wants to find Payments where testing = value of testing
attribute
for the User instance.

6

Hi all,
Thanks for your replies.

I want to get related models like this.

@[email protected]
When @user.testing == true then return @user.payments=(payment.testing
== true)
When @user.testing == false then return
@user.payments=(payment.testing == false)

Therefore “where(:testing => true)” is not suitable for this case.
The payment.testing value depends on user.testing value(same as
user.testing value).

Masuda

7

Tim
You’re exactly right.

Thanks

8

Goro Kuroita wrote in post #968571:

Hi,
I’m developing with ruby-1.9. 1 rails 3.0.0.
I want to relate ‘User’ model and ‘Payment’ model with condition which
has the same value as ‘user.testing’ in ‘payment.testing’

I did

Class User < ActiveRecord::Base
has_many payments, :conditions => [‘testing = ?’, self.testing]
end

This doesn’t work.
I tried also below, but doesn’t work too.
has_many payments, :conditions => [‘testing = ?’,
#{self.send(:testing)}]

Maybe this could work:

class User < ActiveRecord::Base
has_many :payments
has_many :payments_with_testing,
:class_name => ‘Payment’,
:conditions => ‘testing = '#{self.testing}'’
end

and then I get this when running a test:

user_1.inspect
#<User id: 1, first_name: “Tom”, last_name: “Smith”, user_name:
“tom_smith”, testing: “alfa”, created_at: “2010-12-15 21:26:23”,
updated_at: “2010-12-15 21:26:23”>

print user_1.payments [p.id, p.user_id, p.testing]

[[1, 1, “alfa”], [2, 1, “alfa”], [3, 1, “beta”]]

print user_1.payments_with_testing [p.id, p.user_id, p.testing]

[[1, 1, “alfa”], [2, 1, “alfa”]] ### only the associated records with
testing = ‘alfa’ are returned

user_2.inspect
#<User id: 2, first_name: “Chris”, last_name: “Stone”, user_name:
“chris_stone”, testing: “gamma”, created_at: “2010-12-15 21:26:23”,
updated_at: “2010-12-15 21:26:23”>

print user_2.payments [p.id, p.user_id, p.testing]

[[4, 2, “alfa”], [5, 2, “gamma”]]

print user_2.payments_with_testing [p.id, p.user_id, p.testing]

[[5, 2, “gamma”]]

User Load (0.2ms) SELECT “users”.* FROM “users” WHERE (“users”.“id”
= 1) LIMIT 1
Payment Load (0.2ms) SELECT “payments”.* FROM “payments” WHERE
(“payments”.user_id = 1)
Payment Load (0.2ms) SELECT “payments”.* FROM “payments” WHERE
(“payments”.user_id = 1 AND (testing = ‘alfa’))
User Load (0.1ms) SELECT “users”.* FROM “users” WHERE (“users”.“id”
= 2) LIMIT 1
Payment Load (0.1ms) SELECT “payments”.* FROM “payments” WHERE
(“payments”.user_id = 2)
Payment Load (0.1ms) SELECT “payments”.* FROM “payments” WHERE
(“payments”.user_id = 2 AND (testing = ‘gamma’))

This relies on the trick that the condition is only evaluated later in
the proces when quoted with single quotes.
(ref: duncanbeevers' dweebd » has_many with arguments).

I would hope this could be done cleaner with a scope with a lambda,
but I didn’t get this to work straight away.

HTH,

Peter

PS. I used this migration to create the payments table:

class CreatePayments < ActiveRecord::Migration
def self.up
create_table :payments do |t|
t.references :user, :null => false
t.string :testing
t.timestamps
end
end

def self.down
drop_table :payments
end
end

9

On Wed, Dec 15, 2010 at 3:24 PM, Masuda [email protected] wrote:

This doesn’t work.
I tried also below, but doesn’t work too.
has_many payments, :conditions => [‘testing = ?’,
#{self.send(:testing)}]

Any ideas?

I think I got it:

class User < ActiveRecord::Base
has_many :payments
has_many :payments_with_testing,
:class_name => ‘Payment’,
:conditions => ‘testing = '#{self.testing}'’
end

and then I get this when running a test:

user_1.inspect
#<User id: 1, first_name: “Tom”, last_name: “Smith”, user_name:
“tom_smith”, testing: “alfa”, created_at: “2010-12-15 21:26:23”,
updated_at: “2010-12-15 21:26:23”>
user_1.payments (p.id, p.user_id, p.testing)
[[1, 1, “alfa”], [2, 1, “alfa”], [3, 1, “beta”]]
user_1.payments_with_testing (p.id, p.user_id, p.testing)
[[1, 1, “alfa”], [2, 1, “alfa”]] ### only the associated records with
testin = ‘alfa’ are returned
user_2.inspect
#<User id: 2, first_name: “Chris”, last_name: “Stone”, user_name:
“chris_stone”, testing: “gamma”, created_at: “2010-12-15 21:26:23”,
updated_at: “2010-12-15 21:26:23”>
user_2.payments (p.id, p.user_id, p.testing)
[[4, 2, “alfa”], [5, 2, “gamma”]]
user_2.payments_with_testing (p.id, p.user_id, p.testing)
[[5, 2, “gamma”]]

User Load (0.2ms) SELECT “users”.* FROM “users” WHERE (“users”.“id”
= 1) LIMIT 1
Payment Load (0.2ms) SELECT “payments”.* FROM “payments” WHERE
(“payments”.user_id = 1)
Payment Load (0.2ms) SELECT “payments”.* FROM “payments” WHERE
(“payments”.user_id = 1 AND (testing = ‘alfa’))
User Load (0.1ms) SELECT “users”.* FROM “users” WHERE (“users”.“id”
= 2) LIMIT 1
Payment Load (0.1ms) SELECT “payments”.* FROM “payments” WHERE
(“payments”.user_id = 2)
Payment Load (0.1ms) SELECT “payments”.* FROM “payments” WHERE
(“payments”.user_id = 2 AND (testing = ‘gamma’))

This relies on the trick that the condition is only evaluated later in
the proces
when quoted with single quotes.
(ref: duncanbeevers' dweebd » has_many with arguments).

I would hope this could be done cleaner with a scope with a lambda,
but I didn’t get this to work straight away.

HTH,

Peter

PS. I used this migration to create the payments table:

class CreatePayments < ActiveRecord::Migration
def self.up
create_table :payments do |t|
t.references :user, :null => false
t.string :testing
t.timestamps
end
end

def self.down
drop_table :payments
end
end

10

Hi Peter.

Your code worked fine!
It helped me great.

And for all respondent
Thanks for your help.