Has_many, has_one and calling a self.method

Rails
1

Hi
I have the following classes and relations
ServiceDeskTicket
has_many :service_desk_status_histories
has_one :service_desk_resolution

ServiceDeskResolution
belongs_to :service_desk_ticket
def
self.add_resolution_on_convert_to_incident(sd_id,status_id,created_by_id,modified_by_id)
puts 'in resolution status is '+status_id.to_s
end

ServiceDeskStatusHistory
belongs_to :service_desk_ticket
self.add_status_histories_on_convert(sd_id,status_id,created_by_id,modified_by_id)
puts 'called add_status_histories_on_convert
end

Now from ServiceDeskTicket in a def I tried

sd_ticket=self.find(ticket_id)
sd_ticket.service_desk_resolution.add_resolution_on_convert(sd_ticket.id,sd_ticket.service_desk_status_id,created_by,modified_by)
Then I get error
error is undefined method `add_resolution_on_convert’ for
#ServiceDeskResolution:0xb73e2120

       But when I call

sd_ticket.add_status_histories_on_convert(sd_id,status_id,created_by_id,modified_by_id)

   It works properly  Please tell me why this happens

Thanks in advance
Sijo

2

On 24 Sep 2008, at 11:00, Sijo Kg wrote:

      But when I call

sd_ticket
.add_status_histories_on_convert
(sd_id,status_id,created_by_id,modified_by_id)

  It works properly  Please tell me why this happens

Well it shouldn’t be a surprise that calling a class method on an
instance doesn’t work. That’s just the way things work. The second
case is the interesting one. I assume you mean

sd_ticket
.service_desk_status_histories.add_status_histories_on_convert(…)

The reason this works is because
sd_ticket.service_desk_status_histories is a proxy. Conceptually it is
a bit like a scoped version of ServiceDeskStatusHistory (scoped so
that it belongs to sd_ticket).
For example sd_ticket.service_desk_status_histories.find will only
find instances of ServiceDeskStatusHistory belonging to that ticket.
In a similar way class methods are available on this proxy object
(with_scope is used to scope them to the owner)

Fred

3

Hi
Thanks for your reply.Then how can I call class method of
ServiceDeskResolution from ServiceDeskTicket .I also tried like

sd_resolution_obj=ServiceDeskResolution.new
sd_resolution_obj.add_resolution_on_convert_to_incident(sd_ticket.id,sd_ticket.service_desk_status_id,created_by,modified_by)

And the exception caught was
undefined method `add_resolution_on_convert_to_incident’ for
#ServiceDeskResolution:0xb72d66f0
Could you please tell me how can I solve this?

Sijo

4

Hi
Thanks for your reply.Now it works…Actually before I was coding
complete thing in the controller and now I am changing that .And thus
tries to obey the principle of MVC (for example write the DB depenedent
code to corresponding model).But unfortunately till now I have not got a
good tutorial explaining how to separate all these (especially for a
beginner in rails since this is my first industrial project ).I am not
sure any such exists…Since this is a self learning process it may take
time… Isn’t it?

Sijo

5

On 24 Sep 2008, at 11:21, Sijo Kg wrote:

Hi
Thanks for your reply.Then how can I call class method of
ServiceDeskResolution from ServiceDeskTicket .I also tried like

sd_resolution_obj=ServiceDeskResolution.new
sd_resolution_obj
.add_resolution_on_convert_to_incident
(sd_ticket.id,sd_ticket.service_desk_status_id,created_by,modified_by)

And the exception caught was
undefined method `add_resolution_on_convert_to_incident’ for
#ServiceDeskResolution:0xb72d66f0
Could you please tell me how can I solve this?

It’s a class method. call it on the class:

ServiceDeskResolution
.add_resolution_on_convert_to_incident
(sd_ticket.id,sd_ticket.service_desk_status_id,created_by,modified_by)

Fred