Ok, I have an table column that needs to auto-increment, but isn''t the primary key (although I guess it could be). The format for the column is "SR001234" and it needs to autoincrement like so: SR001234 SR001235 SR001236 ... SR999999 How can I do this? I know Ruby has some pretty nice constructs for doing things like this, but I just don''t quite see how to put them into Rails yet. --~--~---------~--~----~------------~-------~--~----~ 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 rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
Could you just add a method to your model that takes the primary key and
returns a string formatted the way you have it listed below?
Something like this:
def get_sr
sr = self.id.to_s
# check the length
raise "id too long" if 6 < sr.length
# pad with zeroes (there''s probably a better way to do this)
(6 - sr.length).times do
sr = "0" + sr
end
return "SR" + sr
end
-Dan
On 9/18/07, JonathanB <doulos05-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:>
>
> Ok, I have an table column that needs to auto-increment, but isn''t
the
> primary key (although I guess it could be). The format for the column
> is "SR001234" and it needs to autoincrement like so:
> SR001234
> SR001235
> SR001236
> ...
> SR999999
>
> How can I do this? I know Ruby has some pretty nice constructs for
> doing things like this, but I just don''t quite see how to put them
> into Rails yet.
>
>
> >
>
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On Sep 18, 2007, at 8:35 PM, Dan Falcone wrote:> Could you just add a method to your model that takes the primary > key and returns a string formatted the way you have it listed below? > > Something like this: > > def get_sr > sr = self.id.to_s > > # check the length > raise "id too long" if 6 < sr.length > > # pad with zeroes (there''s probably a better way to do this) > (6 - sr.length).times do > sr = "0" + sr > end > > return "SR" + srBasing the generation on the very ID is a good approach because you still delegate the generation of sequence to the database. That guarantees it is right. As long as it is OK to save the record without that extra key, and save it afterwards (you don''t have the ID before the INSERT), perhaps with an AR hook. String formatting a la sprintf is easier here: irb(main):001:0> "SR%06d" % 23 => "SR000023" -- fxn --~--~---------~--~----~------------~-------~--~----~ 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 rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---