On Saturday, July 7, 2012 2:09:43 PM UTC-7, Joe Van Dyk wrote:
>
> Given the following:
>
> buyable = DB[:product_listings].where(:buyable => true)
>
> recent = DB[:product_listings].where("start_sale_date > now() - interval
> '1 day'")
>
> What's the best way to find all recent buyable products? (Ideally,
> without using Sequel::Model)
>
> In AR, I'd do:
>
> class ProductListing
> scope :buyable, where(:buyable => true)
> scope :recent, where("start_sale_date > now() - interval '1 day'")
> end
> ProductListing.buyable.recent
>
You probably want to use subset:
class ProductListing
subset :buyable, :buyable => true
subset :recent, "start_sale_date > now() - interval '1 day'"
end
or for more general things that aren't simple where conditions, either
def_dataset_method:
class ProductListing
def_dataset_method(:buyable){where(:buyable => true)}
def_dataset_method(:recent){where("start_sale_date > now() - interval '1
day'")}
end
or dataset_module:
class ProductListing
dataset_module do
def buyable; where(:buyable => true) end
def recent; where("start_sale_date > now() - interval '1 day'") end
end
end
All of those are for Sequel::Model though.
If you really want to get the intersection of products that are both
buyable and recent taking the two separate datasets as input, you want an
SQL INTERSECT query:
DB[:product_listings].where(:buyable =>
true).intersect(DB[:product_listings].where("start_sale_date > now() -
interval '1 day'"))
However, it's rare to actually do that. In most cases you'd just add the
appropriate buyable and recent filter conditions to the same dataset, where
they would be ANDed together in the where clause:
DB[:product_listings].where(:buyable => true).where("start_sale_date >
now() - interval '1 day'")
Jeremy
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