instance method `add_reference`

Ruby on Rails 6.0.6

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:

add_reference(table_name, ref_name, **options)

Adds a reference. The reference column is a bigint by default, the :type option can be used to specify a different type. Optionally adds a _type column, if :polymorphic option is provided. #add_reference and #add_belongs_to are acceptable.

The options hash can include the following keys:

:type: The reference column type. Defaults to :bigint.
:index: Add an appropriate index. Defaults to true. See #add_index for usage of this option.
:foreign_key: Add an appropriate foreign key constraint. Defaults to false.
:polymorphic: Whether an additional _type column should be added. Defaults to false.
:null: Whether the column allows nulls. Defaults to true.

Create a user_id bigint column without an index

add_reference(:products, :user, index: false)

Create a user_id string column

add_reference(:products, :user, type: :string)

Create supplier_id, supplier_type columns

add_reference(:products, :supplier, polymorphic: true)

Create a supplier_id column with a unique index

add_reference(:products, :supplier, index: { unique: true })

Create a supplier_id column with a named index

add_reference(:products, :supplier, index: { name: "my_supplier_index" })

Create a supplier_id column and appropriate foreign key

add_reference(:products, :supplier, foreign_key: true)

Create a supplier_id column and a foreign key to the firms table

add_reference(:products, :supplier, foreign_key: {to_table: :firms})

Parameters

table_name req
ref_name req
options keyrest

Source

# File activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb, line 904
      def add_reference(table_name, ref_name, **options)
        ReferenceDefinition.new(ref_name, **options).add_to(update_table_definition(table_name, self))
      end

Defined in activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb line 904 · View on GitHub · Improve this page · Find usages on GitHub

Defined in ActiveRecord::ConnectionAdapters::SchemaStatements

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