Method `delete_all` should not be invoking callbacks and this
feature was deprecated in Rails 4.0. This is being removed.
`delete_all` will continue to honor the `:dependent` option. However
if `:dependent` value is `:destroy` then the default deletion
strategy for that collection will be applied.
User can also force a deletion strategy by passing parameter to
`delete_all`. For example you can do `@post.comments.delete_all(:nullify)`
Don't use this:
scope :red, where(color: 'red')
default_scope where(color: 'red')
Use this:
scope :red, -> { where(color: 'red') }
default_scope { where(color: 'red') }
The former has numerous issues. It is a common newbie gotcha to do
the following:
scope :recent, where(published_at: Time.now - 2.weeks)
Or a more subtle variant:
scope :recent, -> { where(published_at: Time.now - 2.weeks) }
scope :recent_red, recent.where(color: 'red')
Eager scopes are also very complex to implement within Active
Record, and there are still bugs. For example, the following does
not do what you expect:
scope :remove_conditions, except(:where)
where(...).remove_conditions # => still has conditions
The build_association method was added as an API for plugins
to hook into in 1398db0. This commit restores this API and the
ability to override class.new to return a subclass based on
a virtual attribute in the attributes hash.
