Create an object based on parameters from another

Question

I'm Using Rails 3.2 and i wish to know a " rails way " to create an object based on parameters coming from another. I have the class StoredItem and the class RequestedItem, they are not related, but during the process to attend the requested item i wish to list all itens and qty stored from a requested part number. I thought something like

@requested_items = RequestedItem.includes(:item_description).where("item_request_id = ?", params[:id])

@stored_items = StoredItem.where("item_description_id = ?",@requested_items.item_description_id)

Obviously this seems don't work because i have a lot of descriptions id to compare, not only one, so, whats the best and correct way to make it work?

Any help will be appreciated, thank you :)

j-dexx · Accepted Answer · 2014-03-13 13:35:11Z

3

@stored_items = StoredItem.where("item_description_id IN (?)",@requested_items.map(&:item_description_id))

Or

@stored_items = StoredItem.where(:item_description_id => @requested_items.map(&:item_description_id))

answered Mar 13, 2014 at 13:35

j-dexx

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3 Comments

MrYoshiji Over a year ago

The second option is much better (no pure SQL written which lets Rails deal with the SQL generation, following the DB Adapter). Also, @requested_items.pluck(:item_description_id) would be a little more efficient than a .map(&:item_description_id)

j-dexx Over a year ago

Good point, but depends if he's using requested items elsewhere

drmwndr Over a year ago

Great, i used the second option, it solved my question. Thanks Baloo and MrYoshiji ;)

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