instance method `create_join_table`

Ruby on Rails 4.2.9

Since v4.0.13

Available in: v4.0.13 v4.1.16 v4.2.9 v5.2.8.1 v6.0.6 v6.1.7.10 v7.0.10 v7.1.6 v7.2.3 v8.0.4 v8.1.2

Compare with:

create_join_table(table_1, table_2, options = {})

Creates a new join table with the name created using the lexical order of the first two arguments. These arguments can be a String or a Symbol.

# Creates a table called 'assemblies_parts' with no id.
create_join_table(:assemblies, :parts)

You can pass a options hash can include the following keys:

:table_name: Sets the table name overriding the default
:column_options: Any extra options you want appended to the columns definition.
:options: Any extra options you want appended to the table definition.
:temporary: Make a temporary table.
:force: Set to true to drop the table before creating it. Defaults to false.

Note that create_join_table does not create any indices by default; you can use its block form to do so yourself:

create_join_table :products, :categories do |t|
  t.index :product_id
  t.index :category_id
end

Add a backend specific option to the generated SQL (MySQL)

create_join_table(:assemblies, :parts, options: 'ENGINE=InnoDB DEFAULT CHARSET=utf8')

generates:

CREATE TABLE assemblies_parts (
  assembly_id int NOT NULL,
  part_id int NOT NULL,
) ENGINE=InnoDB DEFAULT CHARSET=utf8

Parameters

table_1 req
table_2 req
options opt = {}

Source

# File activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb, line 275
      def create_join_table(table_1, table_2, options = {})
        join_table_name = find_join_table_name(table_1, table_2, options)

        column_options = options.delete(:column_options) || {}
        column_options.reverse_merge!(null: false)

        t1_column, t2_column = [table_1, table_2].map{ |t| t.to_s.singularize.foreign_key }

        create_table(join_table_name, options.merge!(id: false)) do |td|
          td.integer t1_column, column_options
          td.integer t2_column, column_options
          yield td if block_given?
        end
      end

Defined in activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb line 275 · View on GitHub · Improve this page · Find usages on GitHub

Defined in ActiveRecord::ConnectionAdapters::SchemaStatements

Signature

Add a backend specific option to the generated SQL (MySQL)

Parameters