Rails - Jun 2006 - rails saves it to the database and I don''t want to

Hello:
I am developing a web application to book machines for an event.
so I have an event model
class Event < ActiveRecord::Base
    has_many :datetimes
...
end
and a datetime model
class Datetime < ActiveRecord::Base
    belongs_to :event
...
end

I have developed a view with the event information and information for 
the datetimes. and in the event_controller when I capture a datetime I 
do
@datetime = params ....
@event.datetimes << @datetime.

My problem is that "@event.datetimes<<@datetime" saves the
datetime to
the datetimes table in the database. And after that when I validate the 
event for the datetimes not to overlap if I return an error the bad 
datetime is already saved!!
I don''t want the datetime being saved when I introduce it in the 
database
thanks in advance

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enrique barraorion wrote:
> I am developing a web application to book
> machines for an event.
> so I have an event model
> class Event < ActiveRecord::Base
>    has_many :datetimes
> ...
> end
> and a datetime model
> class Datetime < ActiveRecord::Base
>    belongs_to :event
I think you need to rename your model to something other than Datetime. 
Perhaps EventDateTime.  RoR already has a Datetime class and you''re 
overriding it.

hth,
Bill

I have changed the datetime model for one called event_datetime and it 
still happens, rails saves the datetimes to the database each time I do 
a
logger.debug("hello before")
@event.event_datetimes << @datetime
logger.debug("hello after")

the logs are:
hello before
  SQL (0.001268)   BEGIN
  SQL (0.000426)   INSERT INTO event_datetimes (`end_date`, `event_id`, 
`start_date`, `at_job`) VALUES(''2006-03-15 01:18:00'', 20,
''2006-03-15
00:18:00'', 0)
  SQL (0.002012)   COMMIT
hello after

any other ideas?

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On 6/15/06, enrique barraorion <barraorion@gmail.com>
wrote:
> I have changed the datetime model for one called event_datetime and it
> still happens, rails saves the datetimes to the database each time I do
> a
> logger.debug("hello before")
> @event.event_datetimes << @datetime
> logger.debug("hello after")
>
> the logs are:
> hello before
>   SQL (0.001268)   BEGIN
>   SQL (0.000426)   INSERT INTO event_datetimes (`end_date`, `event_id`,
> `start_date`, `at_job`) VALUES(''2006-03-15 01:18:00'', 20,
''2006-03-15
> 00:18:00'', 0)
>   SQL (0.002012)   COMMIT
> hello after
>
> any other ideas?
Try wrapping the whole update in a transaction.

Isak

It does not work. This is my update method:
def update
    @event = Event.find(params[:id])
    indice = 0;
    param_name = ''datetime'' + indice.to_s

    array_datetimes=[]
    while params[param_name.to_sym]
      @datetime = EventDatetime.new(params[param_name.to_sym])
      is_valid = "is_valid_time" + indice.to_s
      if(params[is_valid.to_sym]=="true")
          array_datetimes << @datetime
      end
      indice+=1
      param_name = ''datetime'' + indice.to_s
    end

    #this two following lines save the event_datetimes to the database
    #and I don''t want to
    @event.event_datetimes=[]
    @event.event_datetimes << array_datetimes.reverse
    if !@event.update_attributes(params[:event]) || !@event.save
      render :action => ''edit'', :id => @event
    else
      flash[:notice] = ''Event was successfully updated.''
      redirect_to :action => ''show'', :id => @event
    end
  end

I think the problem can be that I do "@event =
Event.find(params[:id])",
this takes the event from the database and when I change event_datetimes 
(that is in another table) It saves it. This does not happen if instead 
Event.find(params[:id]) i do "@event = Event.new" then 
@event.event_datetimes << array_datetimes.reverse won''t save it
to the
database, and @event.save will do that but with another id, and if I do 
@event.id = params[:id] mysql throws an exception.
i am desperate, I need to update the event but does not work. Does this 
happen allways, I mean that rails saves the attributes to the database 
instead of just saving it to the object an to the database when doing 
save?
thanks

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hello enrique,
I will try to help you...
I don''t really understand why rails save your event_datetimes yet but 
there are something I am not sure in your code ...maybe you can try..
well, first:
if you do an update of the event,
why do you reset the event_datetimes array @event.event_datetimes=[], in 
a has_many the @event.event_datetimes will return the array of 
event_datetimes ...(since you are in an update process)
=> don''t reset your array and just:

@event.event_datetimes << array_datetimes.reverse

If it still does not work, please tell me since i am working on a same database
model I will try with my model...

arnaud



enrique barraorion a ?crit :
>It does not work. This is my update method:
>def update
>    @event = Event.find(params[:id])
>    indice = 0;
>    param_name = ''datetime'' + indice.to_s
>
>    array_datetimes=[]
>    while params[param_name.to_sym]
>      @datetime = EventDatetime.new(params[param_name.to_sym])
>      is_valid = "is_valid_time" + indice.to_s
>      if(params[is_valid.to_sym]=="true")
>          array_datetimes << @datetime
>      end
>      indice+=1
>      param_name = ''datetime'' + indice.to_s
>    end
>
>    #this two following lines save the event_datetimes to the database
>    #and I don''t want to
>    @event.event_datetimes=[]
>    @event.event_datetimes << array_datetimes.reverse
>    if !@event.update_attributes(params[:event]) || !@event.save
>      render :action => ''edit'', :id => @event
>    else
>      flash[:notice] = ''Event was successfully updated.''
>      redirect_to :action => ''show'', :id => @event
>    end
>  end
>
>I think the problem can be that I do "@event =
Event.find(params[:id])",
>this takes the event from the database and when I change event_datetimes 
>(that is in another table) It saves it. This does not happen if instead 
>Event.find(params[:id]) i do "@event = Event.new" then 
>@event.event_datetimes << array_datetimes.reverse won''t save
it to the
>database, and @event.save will do that but with another id, and if I do 
>@event.id = params[:id] mysql throws an exception.
>i am desperate, I need to update the event but does not work. Does this 
>happen allways, I mean that rails saves the attributes to the database 
>instead of just saving it to the object an to the database when doing 
>save?
>thanks
>
>  
>

I reset the event_datetimes with @event.event_datetimes=[] because if I 
don''t do that when I do
"@event.event_datetimes<<@datetime" it saves me
another entry of the datetime in the array and if I have 2 entries when 
I update I have 4 an after that 8 an so on.
@event.save really update the attributes of the event but no the tables 
that are related to the event
this is the log for @event.save
UPDATE events SET `service` = ''TeleMeeting'', `quality` =
''512K'', `uri` =
'''', `description` = ''20'', `password` =
''20'', `name` = ''20'' WHERE id = 4
and I also can do a "@event.event_datetimes[0].save" and it updates
the
event_datetimes entry

I am starting to think that the problem is related to the << operator, 
that adds a new datetime to the array and rails saves it to the 
database, but I don''t like this behaviour because if the user
introduces
an entry that is no a valid one when I validate and return an error 
rails has already saved it to the database

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On 6/19/06, enrique barraorion <barraorion@gmail.com>
wrote:
> It does not work. This is my update method:
> def update
>     @event = Event.find(params[:id])
*snip*
>   end
>
> I think the problem can be that I do "@event =
Event.find(params[:id])",
> this takes the event from the database and when I change event_datetimes
> (that is in another table) It saves it. This does not happen if instead
> Event.find(params[:id]) i do "@event = Event.new" then
> @event.event_datetimes << array_datetimes.reverse won''t save
it to the
> database, and @event.save will do that but with another id, and if I do
> @event.id = params[:id] mysql throws an exception.
> i am desperate, I need to update the event but does not work. Does this
> happen allways, I mean that rails saves the attributes to the database
> instead of just saving it to the object an to the database when doing
> save?
> thanks
"If you wish to assign an object to a has_one association without
saving it, use the association.build method (documented below)." -
snipped from this page:
http://api.rubyonrails.org/classes/ActiveRecord/Associations/ClassMethods.html

Or you could use transactions..

def update
  AnyARModel.transaction do
    create and save! stuff here.. if there''s an error, the whole block
is rolled back.
  end
end

GL,
Isak

It has worked!!
thank you very much to all of you. My problem using transactions was 
that I was using save instead of save! and it did not launched an 
exception and finished the transaction with a commit instead of 
rollback.

just for your information associations worked the same way as <<, build 
added new entries to the array but it did not update the ones that were 
there before

thank you all

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