I want to implement a scope overdue in a model Invoice to return all invoices that exceeded the date, until they had to be paid. I have the fields invoice_date, :type => Date and days_for_payment, :type => Integer.
In my previous version, which was built on ActiveRecord, I could use the query
Invoice.where("invoice_date + days_for_payment < ?", Date.today)
This query made the calculation on the DB side.
Is there a way to get the same thing done with Mongoid? Or does anyone know a good workaround (proc, lambda, etc.)?
I use mongoid '2.4.12'
Found the answer myself. With the prefix this.* I can reference to the fields. And I can use JavaScript functions. MongoDB gets cooler and cooler!
So here is my solution:
class Invoice
include Mongoid::Document
field :invoice_date, :type => Date
field :days_for_payment, :type => Integer
...
scope :overdue, where("(Math.round(this.invoice_date.getTime() / 1000) + (this.days_for_payment * 24 * 3600)) < #{Time.now.to_i}")
...
end
Timestamp creation in js works different. So I had to get rid of the last three numbers and round them.
If anybody knows a more elegant way, please let me know.
My only problem left is, that I can't store a Date object to MongoDB. It always tells me I have to use Time. I think I better upgrade mongoid to 3.0.1.
I am not sure about mongoid, if you are querying mongodb directly you can use the $where operator. It is not recommended as it doesn't use indexes. If you have another condition that filters the records to a small set then you can use the $where to further filter it.
