From: Jason Cameron <cameronjc2000@...>
Date: 2011-01-27T01:42:54+09:00
Subject: Re: to use AR or not? (table defined in code)

Brian Candler wrote in post #977595:
> Jason Cameron wrote in post #977491:
>> rate_type  location   algorithm  rate
>> BCD        Here       simple     1.2
>> ATD        There      fractal    4.3
>> STE        Elsewhere  binary     3.2
>> TSO        Really Far polyamory  0.1
>>
>> I need to be able to create a data structure that I can search easily.
>> Enabling bulk inserts of some sort would be nice as well.
>>
>> At the moment I'm looking at activerecord-tableless.  Unfortunately I'm
>> not entirely sure how to create a bunch of activerecords (not just one
>> at a time)
>>
>> Is there a better alternative?
>
> activerecord-tableless won't give you *any* searching functionality.
> It's basically just model validations. If you don't need AR-style
> validations then you might as well just use OpenStruct (ostruct.rb in
> the core library)
>
> I'd say the key points to consider are:
>
> * What sort of searching do you want to do?
> * Do you want persistence, or will you always reload your data every
> time your application is re-run?
>
> If your database is small and/or your queries are complex, you might
> just want to search using a linear scan.
>
>    objs.find { |o| ... condition ... }
>
> If you need an indexed search but you only want to search on one field
> at a time (e.g. find all fields with location "Here") then you can just
> build hash indexes for yourself.
>
> If you want to persist this Ruby object structure you've built, then you
> could use something like Madeleine.
>
> If you want to keep everything in memory but have some basic querying
> like unions and intersections, maybe "redis" is what you're after. By
> leaving the redis daemon running your data can persist in memory and be
> accessible to multiple scripts (in ruby and/or other languages).
>
> If you want arbitrary querying, indexes and persistence to disk, then
> you'd almost certainly be better off with something like sqlite.
>
> Regards,
>
> Brian.

Hmmm after some digging I found Struct.  How different is that from 
OpenStruct?  The following code is what I came up with:

cs = Struct.new(:rate_type,  :location,   :algorithm,  :rate)
cs_col = []
cs_col.push(cs.new('BCD', 'Here', 'simple', 1.2))
cs_col.push(cs.new('ATD', 'There', 'fractal', 4.3))
cs_col.push(cs.new('STE', 'Elsewhere', 'fractal', 3.2))
cs_col.push(cs.new('TSO', 'Really Far', 'polyamory', 0.1))

puts cs_col.find {|i| i.location == 'Elsewhere'}.rate

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