Rails model with unique string field (Postgres)

UPDATE: Using a Postgres UUID field is a great way if you don’t care about the format of the unique field. See http://blog.arkency.com/2014/10/how-to-start-using-uuid-in-activerecord-with-postgresql/

	# Add a unique index in your migrations like this:
	# add_index :table, :code, unique: true
	before_create :set_code
	around_save :save_with_unique_code
	def self.generate_code
	SecureRandom.hex(2).upcase
	end
	def set_code(force = false)
	self.code = self.class.generate_code if code.nil? || force
	end
	def save_with_unique_code
	begin
	self.class.connection.execute("SAVEPOINT before_record_create;")
	yield
	# NOTE: be careful if you have other unique fields!
	rescue ActiveRecord::RecordNotUnique
	set_code(true)
	self.class.connection.execute("ROLLBACK TO SAVEPOINT before_record_create;")
	retry
	end
	end

view raw

model_unique_field.rb

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