method

lock!

v5.1.7 - Show latest stable - Class: ActiveRecord::Locking::Pessimistic

lock!(lock = true)

public

Obtain a row lock on this record. Reloads the record to obtain the requested lock. Pass an SQL locking clause to append the end of the SELECT statement or pass true for “FOR UPDATE” (the default, an exclusive row lock). Returns the locked record.

# File activerecord/lib/active_record/locking/pessimistic.rb, line 61
      def lock!(lock = true)
        if persisted?
          if has_changes_to_save?
            ActiveSupport::Deprecation.warn(              Locking a record with unpersisted changes is deprecated and will raise an              exception in Rails 5.2. Use `save` to persist the changes, or `reload` to              discard them explicitly..squish)
          end
          reload(lock: lock)
        end
        self
      end

1Note

Only works within a transaction

yeah · Oct 27, 20091 thank

Of course, this has to be done in a transaction, like so:

# we've loaded user earlier and did some checks which took some time
# to make sure, updates made meanwhile by other threads don't lead to
# optimistic locking errors here, we do this when finally suspending
User.transaction do
user.lock!
user.suspended = 1
user.save!
end

lock!

1Note

Only works within a transaction

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