Database design for an online organization tool

Question

I'm a big fan of David Allen's Getting Things Done, but the myriad software tools and sites I've tried haven't impressed me that much. That's why I've decided to write my own.

The concept

This app (I don't have a name for it yet.) pulls in your twitter stream, Facebook news feeds, email, RSS feeds, and more and treats them like items in your GTD inbox, sorted by importance, dependent on who sent you the message. Once everything has been gathered, it's your job to look at each item and decide what to do with it.

SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0;
SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0;
SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='TRADITIONAL';
CREATE SCHEMA IF NOT EXISTS `DoneBox` DEFAULT CHARACTER SET latin1 COLLATE latin1_swedish_ci ;
USE `DoneBox` ;
-- -----------------------------------------------------
-- Table `DoneBox`.`users`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `DoneBox`.`users` (
 `id` CHAR(16) BINARY NOT NULL ,
 `username` VARCHAR(50) NULL ,
 `password` VARCHAR(150) NULL ,
 `email` VARCHAR(100) NULL ,
 `recovery_answer_1` TEXT NULL ,
 `recovery_answer_2` TEXT NULL ,
 `phone` VARCHAR(45) NULL ,
 PRIMARY KEY (`id`) )
ENGINE = InnoDB;
CREATE UNIQUE INDEX `username_UNIQUE` ON `DoneBox`.`users` (`username` ASC) ;
-- -----------------------------------------------------
-- Table `DoneBox`.`Imap`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `DoneBox`.`Imap` (
 `id` CHAR(16) BINARY NOT NULL ,
 `host` VARCHAR(100) NULL ,
 `port` INT NULL ,
 `ssl` TINYINT(1) NULL ,
 PRIMARY KEY (`id`) )
ENGINE = InnoDB;
-- -----------------------------------------------------
-- Table `DoneBox`.`smtp`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `DoneBox`.`smtp` (
 `id` CHAR(16) BINARY NOT NULL ,
 `host` VARCHAR(100) NULL ,
 `port` INT NULL ,
 `ssl` TINYINT(1) NULL ,
 PRIMARY KEY (`id`) )
ENGINE = InnoDB;
-- -----------------------------------------------------
-- Table `DoneBox`.`pop3`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `DoneBox`.`pop3` (
 `id` CHAR(16) BINARY NOT NULL ,
 `host` VARCHAR(100) NULL ,
 `port` INT NULL ,
 `ssl` TINYINT(1) NULL ,
 PRIMARY KEY (`id`) )
ENGINE = InnoDB;
-- -----------------------------------------------------
-- Table `DoneBox`.`email_provider`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `DoneBox`.`email_provider` (
 `id` CHAR(16) NOT NULL ,
 `domain` VARCHAR(100) NULL ,
 `long_domain` VARCHAR(100) NULL ,
 `Imap_id` CHAR(16) BINARY NOT NULL ,
 `pop3_id` CHAR(16) BINARY NOT NULL ,
 `smtp_id` CHAR(16) BINARY NOT NULL ,
 PRIMARY KEY (`id`, `Imap_id`, `pop3_id`, `smtp_id`) ,
 CONSTRAINT `fk_email_provider_Imap1`
 FOREIGN KEY (`Imap_id` )
 REFERENCES `DoneBox`.`Imap` (`id` )
 ON DELETE NO ACTION
 ON UPDATE NO ACTION,
 CONSTRAINT `fk_email_provider_pop31`
 FOREIGN KEY (`pop3_id` )
 REFERENCES `DoneBox`.`pop3` (`id` )
 ON DELETE NO ACTION
 ON UPDATE NO ACTION,
 CONSTRAINT `fk_email_provider_smtp1`
 FOREIGN KEY (`smtp_id` )
 REFERENCES `DoneBox`.`smtp` (`id` )
 ON DELETE NO ACTION
 ON UPDATE NO ACTION)
ENGINE = InnoDB;
CREATE INDEX `fk_email_provider_Imap1` ON `DoneBox`.`email_provider` (`Imap_id` ASC) ;
CREATE INDEX `fk_email_provider_pop31` ON `DoneBox`.`email_provider` (`pop3_id` ASC) ;
CREATE INDEX `fk_email_provider_smtp1` ON `DoneBox`.`email_provider` (`smtp_id` ASC) ;
-- -----------------------------------------------------
-- Table `DoneBox`.`email_account`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `DoneBox`.`email_account` (
 `id` CHAR(16) BINARY NOT NULL ,
 `email` VARCHAR(100) NULL ,
 `password` VARCHAR(150) NULL ,
 `signature` VARCHAR(45) NULL ,
 `email_provider_id` CHAR(16) NOT NULL ,
 `users_id` CHAR(16) BINARY NOT NULL ,
 PRIMARY KEY (`id`, `email_provider_id`, `users_id`) ,
 CONSTRAINT `fk_email_account_email_provider1`
 FOREIGN KEY (`email_provider_id` )
 REFERENCES `DoneBox`.`email_provider` (`id` )
 ON DELETE NO ACTION
 ON UPDATE NO ACTION,
 CONSTRAINT `fk_email_account_users1`
 FOREIGN KEY (`users_id` )
 REFERENCES `DoneBox`.`users` (`id` )
 ON DELETE NO ACTION
 ON UPDATE NO ACTION)
ENGINE = InnoDB;
CREATE INDEX `fk_email_account_email_provider1` ON `DoneBox`.`email_account` (`email_provider_id` ASC) ;
CREATE INDEX `fk_email_account_users1` ON `DoneBox`.`email_account` (`users_id` ASC) ;
-- -----------------------------------------------------
-- Table `DoneBox`.`contexts`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `DoneBox`.`contexts` (
 `id` CHAR(16) BINARY NOT NULL ,
 `name` VARCHAR(100) NULL ,
 `users_id` CHAR(16) BINARY NOT NULL ,
 PRIMARY KEY (`id`, `users_id`) ,
 CONSTRAINT `fk_contexts_users1`
 FOREIGN KEY (`users_id` )
 REFERENCES `DoneBox`.`users` (`id` )
 ON DELETE NO ACTION
 ON UPDATE NO ACTION)
ENGINE = InnoDB;
CREATE INDEX `fk_contexts_users1` ON `DoneBox`.`contexts` (`users_id` ASC) ;
-- -----------------------------------------------------
-- Table `DoneBox`.`projects`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `DoneBox`.`projects` (
 `id` CHAR(16) BINARY NOT NULL ,
 `name` VARCHAR(100) NULL ,
 `description` LONGTEXT NULL ,
 `contexts_id` CHAR(16) BINARY NOT NULL ,
 `users_id` CHAR(16) BINARY NOT NULL ,
 PRIMARY KEY (`id`, `contexts_id`, `users_id`) ,
 CONSTRAINT `fk_projects_contexts1`
 FOREIGN KEY (`contexts_id` )
 REFERENCES `DoneBox`.`contexts` (`id` )
 ON DELETE NO ACTION
 ON UPDATE NO ACTION,
 CONSTRAINT `fk_projects_users1`
 FOREIGN KEY (`users_id` )
 REFERENCES `DoneBox`.`users` (`id` )
 ON DELETE NO ACTION
 ON UPDATE NO ACTION)
ENGINE = InnoDB;
CREATE INDEX `fk_projects_contexts1` ON `DoneBox`.`projects` (`contexts_id` ASC) ;
CREATE INDEX `fk_projects_users1` ON `DoneBox`.`projects` (`users_id` ASC) ;
-- -----------------------------------------------------
-- Table `DoneBox`.`email_messages`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `DoneBox`.`email_messages` (
 `id` CHAR(16) NOT NULL ,
 `sender` VARCHAR(100) NULL ,
 `sent_on` DATETIME NULL ,
 `subject` VARCHAR(45) NULL ,
 `body` LONGTEXT NULL ,
 `is_unread` TINYINT(1) NULL ,
 `email_account_id` CHAR(16) BINARY NOT NULL ,
 `users_id` CHAR(16) BINARY NOT NULL ,
 `projects_id` CHAR(16) BINARY NOT NULL ,
 `contexts_id` CHAR(16) BINARY NOT NULL ,
 PRIMARY KEY (`id`, `email_account_id`, `users_id`, `projects_id`, `contexts_id`) ,
 CONSTRAINT `fk_email_messages_email_account1`
 FOREIGN KEY (`email_account_id` )
 REFERENCES `DoneBox`.`email_account` (`id` )
 ON DELETE NO ACTION
 ON UPDATE NO ACTION,
 CONSTRAINT `fk_email_messages_users1`
 FOREIGN KEY (`users_id` )
 REFERENCES `DoneBox`.`users` (`id` )
 ON DELETE NO ACTION
 ON UPDATE NO ACTION,
 CONSTRAINT `fk_email_messages_projects1`
 FOREIGN KEY (`projects_id` )
 REFERENCES `DoneBox`.`projects` (`id` )
 ON DELETE NO ACTION
 ON UPDATE NO ACTION,
 CONSTRAINT `fk_email_messages_contexts1`
 FOREIGN KEY (`contexts_id` )
 REFERENCES `DoneBox`.`contexts` (`id` )
 ON DELETE NO ACTION
 ON UPDATE NO ACTION)
ENGINE = InnoDB;
CREATE INDEX `fk_email_messages_email_account1` ON `DoneBox`.`email_messages` (`email_account_id` ASC) ;
CREATE INDEX `fk_email_messages_users1` ON `DoneBox`.`email_messages` (`users_id` ASC) ;
CREATE INDEX `fk_email_messages_projects1` ON `DoneBox`.`email_messages` (`projects_id` ASC) ;
CREATE INDEX `fk_email_messages_contexts1` ON `DoneBox`.`email_messages` (`contexts_id` ASC) ;
-- -----------------------------------------------------
-- Table `DoneBox`.`social_account`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `DoneBox`.`social_account` (
 `id` CHAR(16) BINARY NOT NULL ,
 `service` VARCHAR(100) NULL ,
 `username` VARCHAR(100) NULL ,
 `send` INT(11) NULL ,
 `receive` INT(11) NULL ,
 `key` VARCHAR(200) NULL ,
 `json` LONGTEXT NULL ,
 `users_id` CHAR(16) BINARY NOT NULL ,
 PRIMARY KEY (`id`, `users_id`) ,
 CONSTRAINT `fk_social_account_users1`
 FOREIGN KEY (`users_id` )
 REFERENCES `DoneBox`.`users` (`id` )
 ON DELETE NO ACTION
 ON UPDATE NO ACTION)
ENGINE = InnoDB;
CREATE INDEX `fk_social_account_users1` ON `DoneBox`.`social_account` (`users_id` ASC) ;
-- -----------------------------------------------------
-- Table `DoneBox`.`social_messages`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `DoneBox`.`social_messages` (
 `id` CHAR(16) BINARY NOT NULL ,
 `sender` VARCHAR(200) NULL ,
 `messaage_id` VARCHAR(200) NULL ,
 `operation` TEXT NULL ,
 `transient` TEXT NULL ,
 `stream` VARCHAR(45) NULL ,
 `time` TIME NULL ,
 `from_me` INT(11) NULL ,
 `to_me` VARCHAR(45) NULL ,
 `json` VARCHAR(45) NULL ,
 `social_account_id` CHAR(16) BINARY NOT NULL ,
 `users_id` CHAR(16) BINARY NOT NULL ,
 `projects_id` CHAR(16) BINARY NOT NULL ,
 `contexts_id` CHAR(16) BINARY NOT NULL ,
 PRIMARY KEY (`id`, `social_account_id`, `users_id`, `projects_id`, `contexts_id`) ,
 CONSTRAINT `fk_social_messages_social_account1`
 FOREIGN KEY (`social_account_id` )
 REFERENCES `DoneBox`.`social_account` (`id` )
 ON DELETE NO ACTION
 ON UPDATE NO ACTION,
 CONSTRAINT `fk_social_messages_users1`
 FOREIGN KEY (`users_id` )
 REFERENCES `DoneBox`.`users` (`id` )
 ON DELETE NO ACTION
 ON UPDATE NO ACTION,
 CONSTRAINT `fk_social_messages_contexts1`
 FOREIGN KEY (`contexts_id` )
 REFERENCES `DoneBox`.`contexts` (`id` )
 ON DELETE NO ACTION
 ON UPDATE NO ACTION,
 CONSTRAINT `fk_social_messages_projects1`
 FOREIGN KEY (`projects_id` )
 REFERENCES `DoneBox`.`projects` (`id` )
 ON DELETE NO ACTION
 ON UPDATE NO ACTION)
ENGINE = InnoDB;
CREATE INDEX `fk_social_messages_social_account1` ON `DoneBox`.`social_messages` (`social_account_id` ASC) ;
CREATE INDEX `fk_social_messages_users1` ON `DoneBox`.`social_messages` (`users_id` ASC) ;
CREATE INDEX `fk_social_messages_contexts1` ON `DoneBox`.`social_messages` (`contexts_id` ASC) ;
CREATE INDEX `fk_social_messages_projects1` ON `DoneBox`.`social_messages` (`projects_id` ASC) ;
-- -----------------------------------------------------
-- Table `DoneBox`.`syndicate_feeds`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `DoneBox`.`syndicate_feeds` (
 `id` CHAR(16) BINARY NOT NULL ,
 `name` VARCHAR(100) NULL ,
 `url` VARCHAR(200) NULL ,
 `users_id` CHAR(16) BINARY NOT NULL ,
 PRIMARY KEY (`id`, `users_id`) ,
 CONSTRAINT `fk_syndicate_feeds_users1`
 FOREIGN KEY (`users_id` )
 REFERENCES `DoneBox`.`users` (`id` )
 ON DELETE NO ACTION
 ON UPDATE NO ACTION)
ENGINE = InnoDB;
CREATE INDEX `fk_syndicate_feeds_users1` ON `DoneBox`.`syndicate_feeds` (`users_id` ASC) ;
-- -----------------------------------------------------
-- Table `DoneBox`.`syndicate_items`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `DoneBox`.`syndicate_items` (
 `id` CHAR(16) BINARY NOT NULL ,
 `title` VARCHAR(100) NULL ,
 `date` DATE NULL ,
 `url` VARCHAR(200) NULL ,
 `body` LONGTEXT NULL ,
 `syndicate_feeds_id` CHAR(16) BINARY NOT NULL ,
 `users_id` CHAR(16) BINARY NOT NULL ,
 `projects_id` CHAR(16) BINARY NOT NULL ,
 `contexts_id` CHAR(16) BINARY NOT NULL ,
 PRIMARY KEY (`id`, `syndicate_feeds_id`, `users_id`, `projects_id`, `contexts_id`) ,
 CONSTRAINT `fk_syndicate_items_syndicate_feeds1`
 FOREIGN KEY (`syndicate_feeds_id` )
 REFERENCES `DoneBox`.`syndicate_feeds` (`id` )
 ON DELETE NO ACTION
 ON UPDATE NO ACTION,
 CONSTRAINT `fk_syndicate_items_users1`
 FOREIGN KEY (`users_id` )
 REFERENCES `DoneBox`.`users` (`id` )
 ON DELETE NO ACTION
 ON UPDATE NO ACTION,
 CONSTRAINT `fk_syndicate_items_projects1`
 FOREIGN KEY (`projects_id` )
 REFERENCES `DoneBox`.`projects` (`id` )
 ON DELETE NO ACTION
 ON UPDATE NO ACTION,
 CONSTRAINT `fk_syndicate_items_contexts1`
 FOREIGN KEY (`contexts_id` )
 REFERENCES `DoneBox`.`contexts` (`id` )
 ON DELETE NO ACTION
 ON UPDATE NO ACTION)
ENGINE = InnoDB;
CREATE INDEX `fk_syndicate_items_syndicate_feeds1` ON `DoneBox`.`syndicate_items` (`syndicate_feeds_id` ASC) ;
CREATE INDEX `fk_syndicate_items_users1` ON `DoneBox`.`syndicate_items` (`users_id` ASC) ;
CREATE INDEX `fk_syndicate_items_projects1` ON `DoneBox`.`syndicate_items` (`projects_id` ASC) ;
CREATE INDEX `fk_syndicate_items_contexts1` ON `DoneBox`.`syndicate_items` (`contexts_id` ASC) ;
-- -----------------------------------------------------
-- Table `DoneBox`.`activation_profile`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `DoneBox`.`activation_profile` (
 `id` CHAR(16) BINARY NOT NULL ,
 `activation_code` VARCHAR(40) NULL ,
 `date` DATE NULL ,
 `users_id` CHAR(16) BINARY NOT NULL ,
 PRIMARY KEY (`id`, `users_id`) ,
 CONSTRAINT `fk_activation_profile_users1`
 FOREIGN KEY (`users_id` )
 REFERENCES `DoneBox`.`users` (`id` )
 ON DELETE NO ACTION
 ON UPDATE NO ACTION)
ENGINE = InnoDB;
CREATE INDEX `fk_activation_profile_users1` ON `DoneBox`.`activation_profile` (`users_id` ASC) ;
CREATE USER `levi` IDENTIFIED BY '<snip>';
grant DELETE on TABLE `DoneBox`.`Imap` to levi;
grant INSERT on TABLE `DoneBox`.`Imap` to levi;
grant SELECT on TABLE `DoneBox`.`Imap` to levi;
grant UPDATE on TABLE `DoneBox`.`Imap` to levi;
grant DELETE on TABLE `DoneBox`.`social_messages` to levi;
grant INSERT on TABLE `DoneBox`.`social_messages` to levi;
grant SELECT on TABLE `DoneBox`.`social_messages` to levi;
grant UPDATE on TABLE `DoneBox`.`social_messages` to levi;
grant DELETE on TABLE `DoneBox`.`contexts` to levi;
grant SELECT on TABLE `DoneBox`.`contexts` to levi;
grant UPDATE on TABLE `DoneBox`.`contexts` to levi;
grant INSERT on TABLE `DoneBox`.`contexts` to levi;
grant DELETE on TABLE `DoneBox`.`pop3` to levi;
grant INSERT on TABLE `DoneBox`.`pop3` to levi;
grant SELECT on TABLE `DoneBox`.`pop3` to levi;
grant UPDATE on TABLE `DoneBox`.`pop3` to levi;
grant DELETE on TABLE `DoneBox`.`syndicate_feeds` to levi;
grant SELECT on TABLE `DoneBox`.`syndicate_feeds` to levi;
grant UPDATE on TABLE `DoneBox`.`syndicate_feeds` to levi;
grant INSERT on TABLE `DoneBox`.`syndicate_feeds` to levi;
grant DELETE on TABLE `DoneBox`.`email_account` to levi;
grant SELECT on TABLE `DoneBox`.`email_account` to levi;
grant UPDATE on TABLE `DoneBox`.`email_account` to levi;
grant INSERT on TABLE `DoneBox`.`email_account` to levi;
grant DELETE on TABLE `DoneBox`.`projects` to levi;
grant INSERT on TABLE `DoneBox`.`projects` to levi;
grant SELECT on TABLE `DoneBox`.`projects` to levi;
grant UPDATE on TABLE `DoneBox`.`projects` to levi;
grant DELETE on TABLE `DoneBox`.`syndicate_items` to levi;
grant INSERT on TABLE `DoneBox`.`syndicate_items` to levi;
grant SELECT on TABLE `DoneBox`.`syndicate_items` to levi;
grant UPDATE on TABLE `DoneBox`.`syndicate_items` to levi;
grant DELETE on TABLE `DoneBox`.`email_messages` to levi;
grant INSERT on TABLE `DoneBox`.`email_messages` to levi;
grant SELECT on TABLE `DoneBox`.`email_messages` to levi;
grant UPDATE on TABLE `DoneBox`.`email_messages` to levi;
grant DELETE on TABLE `DoneBox`.`smtp` to levi;
grant INSERT on TABLE `DoneBox`.`smtp` to levi;
grant SELECT on TABLE `DoneBox`.`smtp` to levi;
grant UPDATE on TABLE `DoneBox`.`smtp` to levi;
grant DELETE on TABLE `DoneBox`.`users` to levi;
grant INSERT on TABLE `DoneBox`.`users` to levi;
grant SELECT on TABLE `DoneBox`.`users` to levi;
grant UPDATE on TABLE `DoneBox`.`users` to levi;
grant DELETE on TABLE `DoneBox`.`email_provider` to levi;
grant INSERT on TABLE `DoneBox`.`email_provider` to levi;
grant SELECT on TABLE `DoneBox`.`email_provider` to levi;
grant UPDATE on TABLE `DoneBox`.`email_provider` to levi;
grant DELETE on TABLE `DoneBox`.`social_account` to levi;
grant INSERT on TABLE `DoneBox`.`social_account` to levi;
grant SELECT on TABLE `DoneBox`.`social_account` to levi;
grant UPDATE on TABLE `DoneBox`.`social_account` to levi;
SET SQL_MODE=@OLD_SQL_MODE;
SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS;
SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS;

MySQL workbench file I used to generate this code.

• This database will be deployed to Amazon RDS.
• I'm using a clojure library called korma to run queries.
• The Imap, smtp, pop3, and email_provider tables are used to keep a local email configuration cache, these could probably be merged.
• I'm using a GUID as the primary key for all my tables.

Does this design make sense? Are there any places I can make improvements? Are the permissions I have set enough? This is my first attempt at trying to design a database for a web app, so any suggestions and advice are greatly appreciated. Thank you for your time and consideration.

• Ron: don't store plaintext passwords
• Ron: why do you have so many composite pk's? why not 0?
• Levi Campbell: @Ron first, I'm using the BCrypt algorithm for the User table and AES for the email_account table, second, I used MySQL workbench to design the database and used an identifying 1:1 and 1:n relationship, is there anything I should have done differently?
• Malachi: why use a GUID for the Primary Keys? why not just use an INT that AUTO_INCREMENT's ????

Answer 1

• consider utf8 charset and collation for your international users

• maximum length of an email address is 320 characters

• maximum length of a phone number is 15 characters, plus 11 for extension (plus 1 for a separator if you want to go that way)

• your user's password should be hashed before it is stored in the database, so should have a fixed length

• email provider passwords should be encrypted

• why nullable for username and password?

• recovery text might be problematic due to celebrities (Sarah Palin had an issue with this)

• consider implications of having to enter 16 digit (GUID) identifiers in urls, or over the phone

• host name can be 255 chars

• signature seems kinda short - I would go with TEXT

• I would use table inheritance pattern for email provider, email/social message

• What does json field mean in social_account?

• I guess you could hash the activation_profile.activation_code , and shorten it to code

• What does activation_profile.date mean?

• url maximum length is 2083 characters

• What about email attachments or Facebook message attachments?

• How are you going to deal with multi-part emails that have an HTML body and a plain-text body, or both or neither?

• E-mail subject maximum length is 78

• You might want to put your index declarations all in one file so that you can drop and add them in one operation (in case of bulk load)

• Levi Campbell: two things, first, I've answered your questions in my original question, second, what's table inheritance? Google has been less then helpful here.
• Neil McGuigan: duh me on the social passwords. was late at night :) regarding inheritance, it looks like messages are pretty similar and providers are pretty similar. you might consider a supertype for each that holds common fields, to ease maintenance over time. i was referring to these patterns: martinfowler.com/eaaCatalog/singleTableInheritance.html martinfowler.com/eaaCatalog/classTableInheritance.html
• Levi Campbell: Ah, thank you very much for your time and effort, I really appreciate it. Now all I have to do is commit the update SQL file to git and I'll be good to go!