#1005 - Can't create table 'feedback.answer' (errno: 150) - mysql

Question

I am getting an error with mysql and I do not understand why:
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,ALLOW_INVALID_DATES';
CREATE SCHEMA IF NOT EXISTS `feedback` DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci ;
USE `feedback` ;
-- -----------------------------------------------------
-- Table `feedback`.`application`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `feedback`.`application` (
`application_id` INT NOT NULL AUTO_INCREMENT,
`app_name` VARCHAR(45) NULL,
PRIMARY KEY (`application_id`),
UNIQUE INDEX `app_name_UNIQUE` (`app_name` ASC))
ENGINE = InnoDB;
-- -----------------------------------------------------
-- Table `feedback`.`user`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `feedback`.`user` (
`user_id` INT NOT NULL AUTO_INCREMENT,
`firstname` VARCHAR(45) NOT NULL,
`lastname` VARCHAR(45) NULL,
`email` VARCHAR(45) NOT NULL,
`customer_length` VARCHAR(45) NULL,
PRIMARY KEY (`user_id`))
ENGINE = InnoDB;
-- -----------------------------------------------------
-- Table `feedback`.`users_has_application`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `feedback`.`users_has_application` (
`user_id` INT NOT NULL,
`application_id` INT NOT NULL,
PRIMARY KEY (`user_id`, `application_id`),
INDEX `fk_users_has_application_application1_idx` (`application_id` ASC),
INDEX `fk_users_has_application_users_idx` (`user_id` ASC),
CONSTRAINT `fk_users_has_application_users`
FOREIGN KEY (`user_id`)
REFERENCES `feedback`.`user` (`user_id`)
ON DELETE NO ACTION
ON UPDATE NO ACTION,
CONSTRAINT `fk_users_has_application_application1`
FOREIGN KEY (`application_id`)
REFERENCES `feedback`.`application` (`application_id`)
ON DELETE NO ACTION
ON UPDATE NO ACTION)
ENGINE = InnoDB;
-- -----------------------------------------------------
-- Table `feedback`.`survey`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `feedback`.`survey` (
`survey_id` INT NOT NULL AUTO_INCREMENT,
`name` VARCHAR(45) NULL,
`description` VARCHAR(255) NULL,
`is_active` TINYINT(1) NULL,
PRIMARY KEY (`survey_id`))
ENGINE = InnoDB;
-- -----------------------------------------------------
-- Table `feedback`.`question`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `feedback`.`question` (
`question_id` INT NOT NULL,
`question_text` VARCHAR(255) NULL,
PRIMARY KEY (`question_id`))
ENGINE = InnoDB;
-- -----------------------------------------------------
-- Table `feedback`.`option`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `feedback`.`option` (
`option_id` INT NOT NULL AUTO_INCREMENT,
`question_id` INT NOT NULL,
`option_number` INT NOT NULL,
`option_text` TEXT NULL,
INDEX `fk_option_question1_idx` (`question_id` ASC),
PRIMARY KEY (`option_id`),
UNIQUE INDEX `uk_question_option_number_key` (`question_id` ASC, `option_number` ASC),
CONSTRAINT `fk_option_question1`
FOREIGN KEY (`question_id`)
REFERENCES `feedback`.`question` (`question_id`)
ON DELETE NO ACTION
ON UPDATE NO ACTION)
ENGINE = InnoDB;
-- -----------------------------------------------------
-- Table `feedback`.`answer`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `feedback`.`answer` (
`answer_id` INT NOT NULL AUTO_INCREMENT,
`user_id` INT NOT NULL,
`option_id` INT NOT NULL,
`date_submitted` DATETIME NOT NULL,
PRIMARY KEY (`answer_id`),
INDEX `fk_answer_user1_idx` (`user_id` ASC),
INDEX `fk_answer_option1_idx` (`option_id` ASC),
CONSTRAINT `fk_answer_user1`
FOREIGN KEY (`user_id`)
REFERENCES `feedback`.`user` (`user_id`)
ON DELETE NO ACTION
ON UPDATE NO ACTION,
CONSTRAINT `fk_answer_option1`
FOREIGN KEY (`option_id`)
REFERENCES `feedback`.`option` (`option_id`)
ON DELETE NO ACTION
ON UPDATE NO ACTION)
ENGINE = InnoDB;
-- -----------------------------------------------------
-- Table `feedback`.`survey_has_question`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `feedback`.`survey_has_question` (
`survey_id` INT NOT NULL,
`question_id` INT NOT NULL,
`question_number` INT NULL,
PRIMARY KEY (`survey_id`, `question_id`),
INDEX `fk_survey_has_question_question1_idx` (`question_id` ASC),
INDEX `fk_survey_has_question_survey1_idx` (`survey_id` ASC),
UNIQUE INDEX `unique_order_key` (`survey_id` ASC, `question_number` ASC),
CONSTRAINT `fk_survey_has_question_survey1`
FOREIGN KEY (`survey_id`)
REFERENCES `feedback`.`survey` (`survey_id`)
ON DELETE NO ACTION
ON UPDATE NO ACTION,
CONSTRAINT `fk_survey_has_question_question1`
FOREIGN KEY (`question_id`)
REFERENCES `feedback`.`question` (`question_id`)
ON DELETE NO ACTION
ON UPDATE NO ACTION)
ENGINE = InnoDB;
SET SQL_MODE=#OLD_SQL_MODE;
SET FOREIGN_KEY_CHECKS=#OLD_FOREIGN_KEY_CHECKS;
SET UNIQUE_CHECKS=#OLD_UNIQUE_CHECKS;
Error:
#1005 - Can't create table 'feedback.answer' (errno: 150)
I am creating my table from this as a template:
https://dba.stackexchange.com/questions/16002/survey-database-design-associate-an-answer-to-a-user/16047#16047
My thought process for adding answer_id to the answer table is that I want users to be able to fill out the same survey multiple times.
Why is the answer table throwing an error?
EDIT:
Server version: 5.5.29-0ubuntu0.12.04.2
I am importing this using phpmyadmin

Answer 1

Your code worked on MYSQL server 5.1 without errors.
A common cause of errno: 150 is when you create a FK constraint that references a PK that does not yet exist. Make sure both your "user" and "option" tables are created first before you create the "answer" table.
To help debug you can remove the FK constraints one at a time to see which one is triggering the problem.
If you execute the code in the order shown, I do not see any FK problems that would occur.

Answer 2

try this
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,ALLOW_INVALID_DATES';
-- -----------------------------------------------------
-- Table `feedback`.`application`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `application` (
`application_id` INT NOT NULL AUTO_INCREMENT,
`app_name` VARCHAR(45) NULL,
PRIMARY KEY (`application_id`),
UNIQUE INDEX `app_name_UNIQUE` (`app_name` ASC))
;
your working code in fiddle