While working with Rails 4 today I was attempting to use the new .not method of ActiveRecord. This method is similar to the jQuery .not method as it allows you to filter your result set where a particular attribute of your result does NOT match what you pass in as .not’s argument. The syntax is:
Post.where.not(author: author)This will also insure that when author is nil the proper sql syntax of IS NOT NULL is used.
I couldn’t find much out on the internet about this method aside from what I had seen on CodeSchool’s Rails 4: Zombie Outlaws and I needed to perform a “not” based on an association. The code school example only covered the simple scenario of a not based on a field on the model you are performing the not on. Here is what worked for associated models:
@@@ruby
scope :purchasable, ->{
includes(:table2)
.includes(:table3)
.where.not(table3: {table2_id: nil})
#.where('table3.table2_id IS NOT NULL')
}Long story short, you need to use nested hashes to utilize associations in your not method calls.
