Module: Sequel::Plugins::MssqlOptimisticLocking

Defined in:
lib/sequel/plugins/mssql_optimistic_locking.rb

Overview

This plugin implements optimistic locking mechanism on Microsoft SQL Server using a timestamp/rowversion column to ensure that concurrent updates are detected and previous changes are not automatically overridden. This is best implemented by a code example:

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

In order for this plugin to work, you need to make sure that the database table has a column of timestamp or rowversion. The plugin uses a default name of timestamp for this columns, but you can override that using the :lock_column option:

plugin :mssql_optimistic_locking, :lock_column=>:column_name

This plugin relies on the instance_filters plugin.

Defined Under Namespace

Modules: ClassMethods, InstanceMethods

Class Method Summary collapse

Class Method Details

.apply(model, opts = OPTS) ⇒ Object

Load the instance_filters plugin into the model.


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# File 'lib/sequel/plugins/mssql_optimistic_locking.rb', line 26

def self.apply(model, opts=OPTS)
  model.plugin :instance_filters
end

.configure(model, opts = OPTS) ⇒ Object

Set the lock_column to the :lock_column option (default: :timestamp)


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# File 'lib/sequel/plugins/mssql_optimistic_locking.rb', line 31

def self.configure(model, opts=OPTS)
  model.lock_column = opts[:lock_column] || :timestamp
end