Concatenate (+) Named scopes leads to creation of an Array, is there a way to have stipp a Scope?

rubyonrails-talk
#1

Hi, I try to explain better, I wrote a named scope like that:

named_scope :with_cellphones_or_emails, {:include => [:cellphones, :emails], :conditions => ["(cellphones.active = ? AND cellphones.customer_id = customers.id) OR (emails.active = ? AND emails.customer_id = customers.id)", true, true]}

for the Customer model, calling Customer.with_cellphones_or_emails takes about 6 seconds on my macbook unibody with 2GB Ram, I've made some tests, I wrote two more named_scopes:

named_scope :with_emails, {:joins => :emails, :conditions => {"emails.active" => true}} named_scope :with_cellphones, {:joins => :cellphones, :conditions => {"cellphones.active" => true}}

running Customer.with_cellphones takes approx. 50ms, Customer.with_emails takes approx 5ms (yeah, my customers have more cellphones than emails! ^_^)... 55ms vs 6s! °_° (these are mysql calculated times)...

Trying to minimize the time spent on db query, by single query, I thought it could be great if I can concatenate the two results, indeed I can do:

Customer.with_cellphones + Customer.with_emails

but the resulting object is an Array, is there a way to obtain an ActiveRecord::NamedScope::Scope object?

Thank you for the answer.

G.

#2

Trying to minimize the time spent on db query, by single query, I thought it could be great if I can concatenate the two results, indeed I can do:

Customer.with_cellphones + Customer.with_emails

but the resulting object is an Array, is there a way to obtain an ActiveRecord::NamedScope::Scope object?

Not that I can think of. even if it did work I expect you;d just end up with a scope that it is equivalent to the first, slow, scope since a scope is by definition not much more than a set of options to pass to a single call to find (or count etc...)

Fred

#3

Hi Frederick, thank you for the anwser.

Not that I can think of. even if it did work I expect you;d just end up with a scope that it is equivalent to the first, slow, scope since a scope is by definition not much more than a set of options to pass to a single call to find (or count etc...)

I can understand, but a find returns an Array, a named_scope, a Scope... It looks like there's a bit of inconsistency on how active record results are showed.. I would have expected that any, ehrm.. say... list of results would be always the same object, and that there would be a way to upgrade a resultset expressed as an Array to a Scope (that's, from what i can see, the same array proxied as a Scope) or any other resultset format used..

G.

#4

a Scope isn't a result set really, just some options for find. (associations are a bit different, but that's a whole other kettle of fish)

Fred