MySQL #1452 - Cannot add or update a child row - mysql

Question

I'm begginer here, all what i'm trying to do is insert into a table field which is a foreign key, please take a look at this two tables :
Table Categorie
CREATE TABLE IF NOT EXISTS `categorie` (
`id_cat` int(2) NOT NULL AUTO_INCREMENT,
`nom_cat` varchar(20) NOT NULL,
PRIMARY KEY (`id_cat`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
and table Annonce
CREATE TABLE IF NOT EXISTS `annonce` (
`id_annonce` int(6) NOT NULL AUTO_INCREMENT,
`titre` varchar(30) NOT NULL,
`description` varchar(255) NOT NULL,
`tarif` float NOT NULL,
`deplacement` int(2) NOT NULL,
`date_creation` date NOT NULL,
`date_expiration` date NOT NULL,
`image` varchar(255) NOT NULL,
`id_cat` int(2) DEFAULT NULL,
PRIMARY KEY (`id_annonce`),
KEY `id_cat` (`id_cat`),
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
After linking the foreign key id_cat manually (ON UPDATE SET NULL ON DELETE CASCADE) that's how the db looks like
and after inserting data into Categorie table it looks like this
But unfortunately i couldn't execute this query :
INSERT INTO annonce (id_annonce, titre, description, tarif, deplacement,
date_creation, date_expiration,id_cat)
VALUES('','anything','anything',2,3,'2017-04-01','2017-04-01',2)
the error says :
1452 - Cannot add or update a child row: a foreign key constraint fails
(lametcom.annonce, CONSTRAINT annonce_ibfk_2 FOREIGN KEY (id_cat)
REFERENCES annonce (id_cat) ON DELETE SET NULL ON UPDATE CASCADE)
Can anyone help please and so sorry about my poor English i hope you can understand what i mean

Answer 1

Your foreign key constraint is wrong. You have
FOREIGN KEY id_cat REFERENCES annonce (id_cat)
but it should be:
FOREIGN KEY id_cat REFERENCES categorie (id_cat)
The table name in the foreign key constraint has to be the table you're linking to.