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Sequel::Plugins::OptimisticLocking

This plugin implements a simple database-independent locking mechanism to ensure that concurrent updates do not override changes. This is best implemented by a code example:

  class Person < Sequel::Model
    plugin :optimistic_locking
  end
  p1 = Person[1]
  p2 = Person[1]
  p1.update(:name=>'Jim') # works
  p2.update(:name=>'Bob') # raises Sequel::Plugins::OptimisticLocking::Error

In order for this plugin to work, you need to make sure that the database table has a lock_version column (or other column you name via the lock_column class level accessor) that defaults to 0.

This plugin relies on the instance_filters plugin.

Constants

Error

Exception class raised when trying to update or destroy a stale object.

Public Class Methods

apply(model, opts={}) click to toggle source

Load the instance_filters plugin into the model.

    # File lib/sequel/plugins/optimistic_locking.rb, line 27
27:       def self.apply(model, opts={})
28:         model.plugin :instance_filters
29:       end
configure(model, opts={}) click to toggle source

Set the lock_column to the :lock_column option, or :lock_version if that option is not given.

    # File lib/sequel/plugins/optimistic_locking.rb, line 33
33:       def self.configure(model, opts={})
34:         model.lock_column = opts[:lock_column] || :lock_version
35:       end

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