2

I am getting the following error when running the below code...what is wrong with it?

Error Code:1170. BLOB/TEXT column 'message" used in key specification without a key length.

-- MySQL Script generated by MySQL Workbench -- Sun Jun 4 21:25:42 2017 -- Model: New Model Version: 1.0 -- MySQL Workbench Forward Engineering 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'; -- ----------------------------------------------------- -- Schema mydb -- ----------------------------------------------------- -- ----------------------------------------------------- -- Schema mydb -- ----------------------------------------------------- CREATE SCHEMA IF NOT EXISTS `mydb` DEFAULT CHARACTER SET utf8 ; USE `mydb` ; -- ----------------------------------------------------- -- Table `mydb`.`users` -- ----------------------------------------------------- CREATE TABLE IF NOT EXISTS `mydb`.`users` ( `id` INT NOT NULL AUTO_INCREMENT, `first_name` VARCHAR(255) NOT NULL, `last_name` VARCHAR(255) NOT NULL, `email` VARCHAR(255) NOT NULL, `password` VARCHAR(255) NOT NULL, `created_at` DATETIME NOT NULL, `updates_at` DATETIME NOT NULL, PRIMARY KEY (`id`), UNIQUE INDEX `first_name_UNIQUE` (`first_name` ASC), UNIQUE INDEX `last_name_UNIQUE` (`last_name` ASC), UNIQUE INDEX `email_UNIQUE` (`email` ASC), UNIQUE INDEX `password_UNIQUE` (`password` ASC), UNIQUE INDEX `created_at_UNIQUE` (`created_at` ASC), UNIQUE INDEX `updates_at_UNIQUE` (`updates_at` ASC)) ENGINE = InnoDB; -- ----------------------------------------------------- -- Table `mydb`.`messages` -- ----------------------------------------------------- CREATE TABLE IF NOT EXISTS `mydb`.`messages` ( `id` INT NOT NULL AUTO_INCREMENT, `users_id` INT NOT NULL, `message` TEXT NOT NULL, `created_at` DATETIME NOT NULL, `updated_at` DATETIME NOT NULL, PRIMARY KEY (`id`), INDEX `fk_messages_users_idx` (`users_id` ASC), UNIQUE INDEX `id_UNIQUE` (`id` ASC), UNIQUE INDEX `users_id_UNIQUE` (`users_id` ASC), UNIQUE INDEX `message_UNIQUE` (`message` ASC), UNIQUE INDEX `created_at_UNIQUE` (`created_at` ASC), UNIQUE INDEX `updated_at_UNIQUE` (`updated_at` ASC), CONSTRAINT `fk_messages_users` FOREIGN KEY (`users_id`) REFERENCES `mydb`.`users` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION) ENGINE = InnoDB; -- ----------------------------------------------------- -- Table `mydb`.`comments` -- ----------------------------------------------------- CREATE TABLE IF NOT EXISTS `mydb`.`comments` ( `id` INT NOT NULL AUTO_INCREMENT, `users_id` INT NOT NULL, `messages_id` INT NOT NULL, `comment` TEXT NOT NULL, `created_at` DATETIME NOT NULL, `updated_at` DATETIME NOT NULL, PRIMARY KEY (`id`), INDEX `fk_comments_users1_idx` (`users_id` ASC), INDEX `fk_comments_messages1_idx` (`messages_id` ASC), UNIQUE INDEX `id_UNIQUE` (`id` ASC), UNIQUE INDEX `users_id_UNIQUE` (`users_id` ASC), UNIQUE INDEX `messages_id_UNIQUE` (`messages_id` ASC), UNIQUE INDEX `comment_UNIQUE` (`comment` ASC), UNIQUE INDEX `created_at_UNIQUE` (`created_at` ASC), UNIQUE INDEX `updated_at_UNIQUE` (`updated_at` ASC), CONSTRAINT `fk_comments_users1` FOREIGN KEY (`users_id`) REFERENCES `mydb`.`users` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION, CONSTRAINT `fk_comments_messages1` FOREIGN KEY (`messages_id`) REFERENCES `mydb`.`messages` (`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; 
2

2 Answers 2

1

InnoDB index maximum length is 767 bytes by default.

When you declare your unique index on your TEXT column, which has a maximum length of 65535 bytes, it exceeds the maximum index length by a lot.

UNIQUE INDEX `message_UNIQUE` (`message` ASC), 

You can enable innodb_large_prefix which makes it possible to make an index of 3072 bytes, that's also much too small for a complete TEXT column.

You can us a prefix index for a TEXT column, but that's not a good solution to enforce uniqueness.

INDEX `message` (`message`(255) ASC), 

You should reconsider whether you need a unique constraint on a TEXT column.

See also:

Sign up to request clarification or add additional context in comments.

Comments

0

It is rare for a table to have 6 unique keys. Even 2 is rare; 1 (the PRIMARY KEY) is typical.

UNIQUE is two things... an index and a uniqueness constraint. As Bill points out, a "prefix" index can achieve a form of indexing. Uniqueness is more complex. If you really need that, then we can discuss it.

A uniqueness constraint on a DATETIME or TIMESTAMP is risky because there (usually) could be two events happening in the same second. It is also rare to need a uniqueness check on "continuous" values like that. (Ditto for FLOAT.)

1 Comment

Thank you! That was helpful! :)

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.