Module: Rein::Constraint::ForeignKey

Included in:
ActiveRecord::ConnectionAdapters::Mysql2Adapter, ActiveRecord::ConnectionAdapters::MysqlAdapter, ActiveRecord::ConnectionAdapters::PostgreSQLAdapter
Defined in:
lib/rein/constraint/foreign_key.rb

Overview

This module contains methods for defining foreign key constraints.

Instance Method Summary collapse

Instance Method Details

#add_foreign_key_constraint(referencing_table, referenced_table, options = {}) ⇒ Object Also known as: add_foreign_key 



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# File 'lib/rein/constraint/foreign_key.rb', line 5

def add_foreign_key_constraint(referencing_table, referenced_table, options = {})
  referencing_attribute = (options[:referencing] || "#{referenced_table.to_s.singularize}_id").to_sym
  referenced_attribute = (options[:referenced] || "id").to_sym

  name = options[:name] || default_constraint_name(referencing_table, referencing_attribute)

  sql = "ALTER TABLE #{referencing_table}"
  sql << " ADD CONSTRAINT #{name}"
  sql << " FOREIGN KEY (#{referencing_attribute})"
  sql << " REFERENCES #{referenced_table} (#{referenced_attribute})"
  sql << " ON DELETE #{referential_action(options[:on_delete])}" if options[:on_delete].present?
  sql << " ON UPDATE #{referential_action(options[:on_update])}" if options[:on_update].present?

  execute(sql)

  # A foreign key constraint doesn't have an implicit index.
  add_index(referencing_table, referencing_attribute) if options[:add_index] == true
end

#remove_foreign_key_constraint(referencing_table, referenced_table, options = {}) ⇒ Object Also known as: remove_foreign_key 



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# File 'lib/rein/constraint/foreign_key.rb', line 25

def remove_foreign_key_constraint(referencing_table, referenced_table, options = {})
  referencing_attribute = options[:referencing] || "#{referenced_table.to_s.singularize}_id".to_sym

  name = options[:name] || default_constraint_name(referencing_table, referencing_attribute)

  if mysql_adapter?
    execute "ALTER TABLE #{referencing_table} DROP FOREIGN KEY #{name}"
  else
    execute "ALTER TABLE #{referencing_table} DROP CONSTRAINT #{name}"
  end

  # A foreign key constraint doesn't have an implicit index.
  remove_index(referencing_table, referencing_attribute) if options[:remove_index] == true
end