Book having many :prices does make sense. That way you get to keep
the history of the price of the book. Of course, the latest price in
the association is the current price.
Ramon Tayag
On Thu, Oct 2, 2008 at 2:05 AM, Anthony E.
<[EMAIL PROTECTED]> wrote:
>
> Robby Russell wrote:
>> On Tue, Sep 30, 2008 at 9:13 PM, Anthony E.
>> <[EMAIL PROTECTED]> wrote:
>>> Something like this:
>>> @book.price = $20.00
>>>
>>> @book.save()
>>> @stats.save()
>>
>> Anthony,
>>
>> Is Book the only model that you'll be doing this for? ...or are there
>> other models that will use this historical log of prices?
>>
>> There's a few options here. One, you could add method to be called by
>> after_save to check the price previously stored with the new one... if
>> they are different... add a new entry to the historical log.
>>
>> Another option is to not store prices in the Book model and only in
>> another table called something like BookPrice.
>>
>> book has_many book_prices
>>
>> Then you can scope book_prices for current to do something like:
>>
>> book.book_prices.current.price # => get the current price
>>
>> book.book_prices.each { |book_price| ... } # => iterate through all
>> book prices
>>
>> Anyhow, there's a few options to throw your way. Good luck!
>>
>> Cheers,
>> Robby
>>
>>
>>
>
> Thanks Robby.
>
> I will be doing this for one model for now, perhaps others down the
> road.
>
> The "Book" model has numeric attributes that I want to save into a
> "statistics" table so I can draw a line-graph over time from it.
>
> Other attributes would be archived as well.
>
> Its sounds to be a before_update would give me access to the current
> price. And I don't want to keep the current price in a stats table
> because that table will eventually grow and slow down the regular query.
>
> book
> ----------
> id
> title
> price
> edition
> year
>
> stats
> ----------
> id
> book_id
> price
> edition
> year
> created_at
> updated_at
>
>
> Ideally sans-rails the stats table would be populated with a trigger
> when the book table is updated.
>
> There book will definitely "has_many :stats" but I don't really want
> that association to be queried every time I get a regular book object,
> only when I build the stats page.
>
>
> --
> Posted via http://www.ruby-forum.com/.
>
> >
>
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