Module: Sequel::Plugins::PreparedStatements

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

Overview

The prepared_statements plugin modifies the model to use prepared statements for instance level deletes and saves, as well as class level lookups by primary key.

Note that this plugin is unsafe in some circumstances, as it can allow up to 2^N prepared statements to be created for each type of insert and update query, where N is the number of colums in the table. It is recommended that you use the prepared_statements_safe plugin in addition to this plugin to reduce the number of prepared statements that can be created, unless you tightly control how your model instances are saved.

This plugin probably does not work correctly with the instance filters plugin.

Usage:

# Make all model subclasses use prepared statements  (called before loading subclasses)
Sequel::Model.plugin :prepared_statements

# Make the Album class use prepared statements
Album.plugin :prepared_statements

Defined Under Namespace

Modules: ClassMethods, InstanceMethods

Constant Summary collapse

MUTEX =

Synchronize access to the integer sequence so that no two calls get the same integer.

Mutex.new
NEXT =

This plugin names prepared statements uniquely using an integer sequence, this lambda returns the next integer to use.

lambda{MUTEX.synchronize{i += 1}}

Class Method Summary collapse

Class Method Details

.apply(model) ⇒ Object

Setup the datastructure used to hold the prepared statements in the model.



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# File 'lib/sequel/plugins/prepared_statements.rb', line 33

def self.apply(model)
  model.instance_variable_set(:@prepared_statements, :insert=>{}, :insert_select=>{}, :update=>{}, :lookup_sql=>{})
end