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Defines the primary key field. Use of the native PostgreSQL UUID type is supported, and can be used by defining your tables as such:
create_table :stuffs, id: :uuid do |t| t.string :content t.timestamps end
By default, this will use the +uuid_generate_v4()+ function from the
uuid-ossp
extension, which MUST be enabled on your databse.
To enable the uuid-ossp
extension, you can use the
enable_extension
method in your migrations To use a UUID
primary key without uuid-ossp
enabled, you can set the
:default
option to nil:
create_table :stuffs, id: false do |t| t.primary_key :id, :uuid, default: nil t.uuid :foo_id t.timestamps end
You may also pass a different UUID generation function from
uuid-ossp
or another library.
Note that setting the UUID primary key default value to nil
will require you to assure that you always provide a UUID value before
saving a record (as primary keys cannot be nil). This might be done via
the SecureRandom.uuid method and a before_save
callback, for
instance.
# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 370 def primary_key(name, type = :primary_key, options = {}) return super unless type == :uuid options[:default] = options.fetch(:default, 'uuid_generate_v4()') options[:primary_key] = true column name, type, options end