method

references

v4.2.1 - Show latest stable - Class: ActiveRecord::ConnectionAdapters::Table

references(*args)

public

Adds a reference. Optionally adds a type column, if :polymorphic option is provided. references and belongs_to are acceptable. The reference column will be an integer by default, the :type option can be used to specify a different type. A foreign key will be created if a foreign_key option is passed.

t.references(:user)
t.references(:user, type: "string")
t.belongs_to(:supplier, polymorphic: true)

See SchemaStatements#add_reference

# File activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb, line 550
      def references(*args)
        options = args.extract_options!
        args.each do |ref_name|
          @base.add_reference(name, ref_name, options)
        end
      end

2Notes

Doesn't add an index

avit · Aug 22, 20084 thanks

Typically you will want to have an index on foreign keys but this method doesn't assume that. Outside of the create_table block you should follow this with add_index :

add_index :table_name, :goat_id
# and, if polymorphic:
add_index :table_name, :goat_type

add index directly

apsoto · Apr 23, 2015

You can add an index now directly on the foreign_key :

t.references(:user, index: true)

references

2Notes

Doesn't add an index

add index directly

Related methods