Cannot add or update a child row .cant insert data - php

Question

cant up date a child raw in my sql
i created the tabels like this :
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
//create the genre table
$genre = #mysql_query( 'CREATE TABLE IF NOT EXISTS genre (
genreName CHAR(15),
rated CHAR(9),
PRIMARY KEY (genreName))
ENGINE innoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;');
if (!$genre) {
exit('<p>Error creating the genre table<br />'.
'Error: ' . mysql_error() . '</p>');
}
if ($genre) {
echo 'everything went just fine with genre table <br>';
}
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
//create the film table
$film = #mysql_query( 'CREATE TABLE IF NOT EXISTS film (
filmID INT(9) auto_increment ,
filmName CHAR(30),
year INT(4),
genreName CHAR(15),
CONSTRAINT FOREIGN KEY (genreName) REFERENCES genre(genreName)ON DELETE CASCADE ON UPDATE CASCADE,
PRIMARY KEY (filmID))
ENGINE innoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;');
if (!$film) {
exit('<p>Error creating the film table<br />'.
'Error: ' . mysql_error() . '</p>');
}
if ($film) {
echo 'everything went just fine with film table <br>'; }
and the tryed to insert data like this:
$sql = "INSERT INTO film (filmName,year,genreName)
VALUES ('The Avengers', '2012','action')";
and got this eror: Error: INSERT INTO film (filmName,year,genreName) VALUES ('The Avengers', '2012','action')
Cannot add or update a child row: a foreign key constraint fails (osherbi.film, CONSTRAINT film_ibfk_1 FOREIGN KEY (genreName) REFERENCES genre (genreName) ON DELETE CASCADE ON UPDATE CASCADE)

Answer 1

I just made a table with your posts and got the code to work. Try this out.
Table structure for table film :
CREATE TABLE IF NOT EXISTS `film` (
`filmID` int(9) NOT NULL,
`filmName` char(30) NOT NULL,
`year` int(6) NOT NULL,
`genreName` char(15) NOT NULL
)
Table structure for table genre :
CREATE TABLE IF NOT EXISTS `genre` (
`genreName` char(15) NOT NULL,
`rated` char(9) NOT NULL
)
Indexes for table film :
ALTER TABLE `film`
ADD PRIMARY KEY (`filmID`), ADD KEY `genreName` (`genreName`);
Indexes for table genre :
ALTER TABLE `genre`
ADD PRIMARY KEY (`genreName`);
Constraints for table film :
ALTER TABLE `film`
ADD CONSTRAINT `film_ibfk_1` FOREIGN KEY (`genreName`) REFERENCES `genre` (`genreName`) ON DELETE CASCADE ON UPDATE CASCADE;
NOTE :
To insert the data, first you need to insert the data to genre table. If you didn't fill up anything in genre table, you fill face error when you insert data to film table since a column genreName is a Foreign key that referencing to genre table genreName column which was initially null.
Add data to genre table like,
INSERT INTO `test1`.`genre` (`genreName`, `rated`) VALUES ('action', '5');
Then, for film table,
INSERT INTO `test1`.`film` (`filmID`, `filmName`, `year`, `genreName`) VALUES ('1', 'The Avengers', '2012', 'action');
I just tested it out. It's working. Good luck!