I can't add a foreign key constraint? Mysql - mysql

Question

I cannot create the second table because Mysql prints out the message with Error Code 12 15, but i do not understand what is the problem in the script..
There are my two tables:
CREATE TABLE IF NOT EXISTS `tsmdb_centralized`.`customer_accounts` (
`id` INT(11) NOT NULL AUTO_INCREMENT,
`customerAccountName` VARCHAR(50) NOT NULL,
`customerAccountUser` VARCHAR(50) NOT NULL,
`customerAccountServer` VARCHAR(45) NOT NULL,
`password` VARCHAR(20) NOT NULL,
`status` TINYINT(50) NOT NULL,
PRIMARY KEY (`id`, `customerAccountServer`))
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8;
-- -----------------------------------------------------
-- Table `tsmdb_centralized`.`bugs_etl`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `tsmdb_centralized`.`bugs_etl` (
`id` INT(11) NOT NULL AUTO_INCREMENT,
`bug_title` VARCHAR(45) NOT NULL,
`bug_description` VARCHAR(500) NULL,
`customerAccountServer` VARCHAR(45) NOT NULL,
PRIMARY KEY (`id`),
INDEX `fk_bugs_etl_customer_accounts_idx` (`customerAccountServer` ASC),
CONSTRAINT `fk_bugs_etl_customer_accounts`
FOREIGN KEY (`customerAccountServer`)
REFERENCES `tsmdb_centralized`.`customer_accounts` (`customerAccountServer`)
ON DELETE NO ACTION
ON UPDATE NO ACTION)
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8;

Answer 1

i found the error, you want to get a foreign key 'CustomerAccountServer' varchar(50) and you can only have a foreign key referencing a unique field. Modify your customer_accounts table so that the customeraccountServer field is unique.
CREATE TABLE IF NOT EXISTS `tsmdb_centralized`.`customer_accounts` (
`id` INT(11) NOT NULL AUTO_INCREMENT,
`customerAccountName` VARCHAR(50) NOT NULL,
`customerAccountUser` VARCHAR(50) NOT NULL,
`customerAccountServer` VARCHAR(45) NOT NULL,
`password` VARCHAR(20) NOT NULL,
`status` TINYINT(50) NOT NULL,
PRIMARY KEY (`id`, `customerAccountServer`),
UNIQUE KEY `customerAccountServer_UNIQUE` (`customerAccountServer`))
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8;

Answer 2

I run this Script:
CREATE TABLE customer_accounts (
id INT(11) NOT NULL AUTO_INCREMENT PRIMARY KEY,
customerAccountName VARCHAR(50) NOT NULL,
customerAccountUser VARCHAR(50) NOT NULL,
customerAccountServer VARCHAR(45) NOT NULL,
password VARCHAR(20) NOT NULL,
status TINYINT(50) NOT NULL,
UNIQUE KEY Cat_customerAccountServer (customerAccountServer)
)
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8;
CREATE TABLE bugs_etl (
id INT(11) NOT NULL AUTO_INCREMENT PRIMARY KEY,
bug_title VARCHAR(45) NOT NULL,
bug_description VARCHAR(500) NULL,
customerAccountServer VARCHAR(45) NOT NULL,
INDEX fk_bugs_etl_customer_accounts_idx(customerAccountServer ASC),
FOREIGN KEY fk_cat(customerAccountServer)
REFERENCES customer_accounts(customerAccountServer)
ON UPDATE NO ACTION
ON DELETE NO ACTION
)
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8;
insert into customer_accounts (customerAccountName,customerAccountUser,
customerAccountServer,password,status)
values('nuevo','nuevo','nuevo','1234',1);
insert into customer_accounts (customerAccountName,customerAccountUser,
customerAccountServer,password,status)
values('nuevo','nuevo','nuevo2','1234',1);
insert into bugs_etl (bug_title,bug_description,
customerAccountServer)
values('nuevo','nuevo','nuevo2');
then i can get:
select * from customer_accounts
join bugs_etl
on customer_accounts.customerAccountServer = bugs_etl.customerAccountServer