On Feb 8, 11:54 pm, Bob Smith <[email protected]> wrote:
> On Feb 8, 7:11 am, Peter Vandenabeele <[email protected]> wrote:
>
>
>
> > On Wed, Feb 8, 2012 at 10:39 AM, Colin Law <[email protected]> wrote:
> > > On 8 February 2012 07:12, Bob Smith <[email protected]> wrote:
> > > > I need a way to set a counter that will show how many of the model
> > > > have been created and put this in each instance. This will allow me to
> > > > use the record number as an input to another field before id is set.
> > > > After things are settled, the real id number can be substituted for
> > > > the counter.
>
> > > If you do that and two users come along at the same time and make new
> > > objects then they will both get the same number. Can you not just use
> > > a before_save filter to set the field? If you think not can you
> > > explain what you are trying to do (and why) in more detail as there is
> > > almost certainly a better solution.
>
> > Maybe the OP really wants a "sequence" (a guaranteed unique number
> > that is more or less monotomically going up).
>
> > The OP may be used to the concept that the primary ID of a record upon
> > creation is such a sequence. But maybe he needs that number _before_
> > the record is saved. (e.g. to set a serial number that is saved in the
> > record).
>
> > If that is the business requirement, 3 solutions:
>
> > 1) don't do it that way. Use a separate sequence generator (which exists
> > in Postgresql and probably in all databases) and use that to calculate
> > the unique and more or less monoticly increasing serial number. Do NOT
> > couple that "business id" with the actual internal database id.
>
> > 2) If you want to use the database id, then you could use an external
> > sequence generator and set the Object.id manually before saving (than
> > configure your db in a way that the primary key is set from the
> > application).
>
> > 3) do an after_create (create the object with most data filled in, the
> > create will generate the database id and in the after_create calculate
> > the other field (e.g. serial number) and save again ... this is then an
> > "update" so the "after_create" will not be triggered again). You may
> > need some more tricks to make sure this "serial number" field cannot
> > be modified, otherwise it could be out of sync with you internal database
> > id (that is "back to (1) above" don't link the "serial number" with the
> > database id, just make it a separate column with a unique index and
> > use a separate sequencer to generate those unique codes).
>
> > HTH,
>
> > Peter
>
> It seems a bit of explanation is in order..
>
> after_create, after_initialize, and the database won't help me.. I
> need this value to be available as soon as new creates a new object in
> the view, before any saving. I have the logic set to do this with
> existing records. What I am trying to do is have a unique value set in
> each new record so that they can be part of a radio button list.
>
> This is how the new objects are created
>
> <%= link_to_function "Add a Person" do |page|
> page.insert_html :bottom, 'empty', :partial => 'shared/
> person', :locals => {:temp => @temp,:household => @household}, :object
> => Person.new
> end %>
>
> My app is used at the signup table of a foodbank. My app has a
> household record that has address, zip, phone, etc. This has a child
> model called people with.. guess what... people :> There are radio
> buttons referencing the record id next to each person where the head
> of household can be selected. This is where the problem lies. No
> problem with existing people, but new ones have no id yet. I have
> added a variable to the people model to hold a counter. I have the
> logic to look back at the record after save, find the id of the wanted
> record, and replace the counter with the correct value. Now all I need
> is a way to set the counter at each new record. Hope this makes it
> clearer.
>
> Thanks
> Bob
Just ALMOST fixed this thanks to google..
in person.rb
def initialize(params = nil)
super()
self.hoh = $hoh
$hoh = $hoh - 1
end
This will set the model to the value in $hoh and decrement it once,
but after that the $hoh = $hoh - 1 won't execute. If I make more than
1 record, all values are the same.. Please help!!
Thanks
Bob
--
You received this message because you are subscribed to the Google Groups "Ruby
on Rails: Talk" group.
To post to this group, send email to [email protected].
To unsubscribe from this group, send email to
[email protected].
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en.
