checking arrays if exist efficiently

[Soichi Ishida]

Rails 4.0.0

I am developing an app that checkes information updates automatically.
When the checking algorithms get to work, they receive an array of
contents such as

info_obtained: ['Tom', 'Steven', 'Bill', ...]

then, the app needs to check if each element of the array is already
persisted in the database.

Of course, I can loop through all elements like

Info.all.each do | i |
if i == ... then
Info.create(... => i)
end
end

But it seems inefficient.

Is there better ways or gems that do the job I am looking for?

soichi

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[jainvi...@gmail.com]

Please, You not fetch all rows from database table. For better way is, you can fetch data with filter using 'where' cluase and Proceed on data.

[Pry Flack]

Soichi Ishida wrote in post #1112146:
> Rails 4.0.0

> Of course, I can loop through all elements like
>
> Info.all.each do | i |
> if i == ... then
> Info.create(... => i)
> end
> end
>
> But it seems inefficient.
>
> Is there better ways or gems that do the job I am looking for?
>
> soichi

Not sure I understand fully your problem.

Maybe use find_in_batches ?
http://api.rubyonrails.org/classes/ActiveRecord/Batches.html

or find_and_create_by_column_name ?
http://api.rubyonrails.org/classes/ActiveRecord/Base.html

[Tamara Temple]

It's also not clear to me what you're doing with the items. From your
snippet of pseudocode, you want to *create* a *new* item with the
matching item when you find a match??

[Soichi Ishida]

Sorry about my poor coding and language skills. I appreciate your
comments.

> Maybe use find_in_batches ?

> or find_and_create_by_column_name ?

will probably help. I'll take a look.

thanks