Mysql error 1215 - Cannot add foreign key constraint - mysql

Question

Created these two tables successfully
First table
CREATE TABLE IF NOT EXISTS `lawncare_user` (
`ID` int(11) NOT NULL AUTO_INCREMENT PRIMARY KEY,
`FirstName` varchar(255) NOT NULL,
`LastName` varchar(255) NOT NULL,
`Email` varchar(255) NOT NULL,
`UserType` varchar(30) NOT NULL,
`UserName` varchar(255) NOT NULL,
`Password` varchar(255) NOT NULL,
`AddedBy` int(11) NOT NULL,
`AddedOn` date NOT NULL,
`ModifiedOn` date DEFAULT NULL,
`Status` BOOLEAN NOT NULL DEFAULT '0',
`QuestionID` int(11) DEFAULT NULL,
`QuestionAnswer` text DEFAULT NULL,
`Params` text NOT NULL,
`Address` text NOT NULL,
`Country` varchar(300) NOT NULL,
`State` varchar(300) NOT NULL,
`City` varchar(300) NOT NULL,
`ContactNo` double DEFAULT NULL,
`Activation` BOOLEAN NOT NULL DEFAULT '0',
`ActivatedOn` date DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
Second table
CREATE TABLE IF NOT EXISTS `lawncare_customer` (
`ID` int(11) NOT NULL AUTO_INCREMENT PRIMARY KEY,
`FirstName` varchar(255) NOT NULL,
`LastName` varchar(255) NOT NULL,
`Email` varchar(255) NOT NULL,
`Password` varchar(255) NOT NULL,
`ContactNo` varchar(20) NOT NULL,
`Address` varchar(255) NOT NULL,
`Params` text NOT NULL,
`Province` varchar(255) NOT NULL,
`ZipCode` varchar(255) NOT NULL,
`Status` Boolean NOT NULL DEFAULT '0',
`AddedBy` int(11) NOT NULL,
`AddedOn` date NOT NULL,
`ModifiedOn` date DEFAULT NULL
) ENGINE =InnoDB DEFAULT CHARSET=latin1;
But while creating third table as
CREATE TABLE IF NOT EXISTS `lawncare_message` (
`ID` int(11) NOT NULL AUTO_INCREMENT PRIMARY KEY,
`Reason` int(5) NOT NULL,
`Subject` text NOT NULL,
`Description` text NOT NULL,
`Customer` int(11) NOT NULL,
`CustomerUser` varchar(255) NOT NULL,
`CustomerEmail` varchar(255) NOT NULL,
`SendTo` int(11) NOT NULL,
`SendToUser` varchar(255) NOT NULL,
`SendToEmail` varchar(255) NOT NULL,
`Status` int(5) NOT NULL DEFAULT '0',
`AddedBy` int(11) NOT NULL,
`AddedOn` date NOT NULL
FOREIGN KEY (SendTo, SendToUser, SendToEmail)
REFERENCES lawncare_user(ID, UserName, Email)
ON UPDATE CASCADE ,
FOREIGN KEY (Customer, CustomerUser, CustomerEmail)
REFERENCES lawncare_customer(ID, FirstName,Email)
ON UPDATE CASCADE
) ENGINE =InnoDB DEFAULT CHARSET=latin1
I get #1215 - Cannot add foreign key constraint , error in mysql tried adding foreign keys after creating table but it still gives the same error. I don't know what I'm doing wrong here.

Answer 1

First of all Check whether you have applied indexes on the keys.
As per your code their is no point in referencing id,UserName and Email.
Only id is enough for referencing.
Check the following code
CREATE TABLE IF NOT EXISTS `lawncare_message` (
`ID` int(11) NOT NULL AUTO_INCREMENT PRIMARY KEY,
`Reason` int(5) NOT NULL,
`Subject` text NOT NULL,
`Description` text NOT NULL,
`Customer` int(11) NOT NULL,
`CustomerUser` varchar(255) NOT NULL,
`CustomerEmail` varchar(255) NOT NULL,
`SendTo` int(11) NOT NULL,
`SendToUser` varchar(255) NOT NULL,
`SendToEmail` varchar(255) NOT NULL,
`Status` int(5) NOT NULL DEFAULT '0',
`AddedBy` int(11) NOT NULL,
`AddedOn` date NOT NULL,
FOREIGN KEY (SendTo)
REFERENCES lawncare_user(ID)
ON UPDATE CASCADE ,
FOREIGN KEY (Customer)
REFERENCES lawncare_customer(ID)
ON UPDATE CASCADE
) ENGINE =InnoDB DEFAULT CHARSET=latin1