Field 'foreign key' doesn't have a default value - mysql

Question

I developed my backend using nodeJS and MySQL, which I have three tables as below :
Fournisseurs:
CREATE TABLE fournisseurs (
Codef bigint(21) NOT NULL ,
Noment varchar(20) COLLATE utf8_unicode_ci NOT NULL,
Prenomf varchar(20) COLLATE utf8_unicode_ci NOT NULL,
PRIMARY KEY (Codef, Prenomf)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;
Categorie :
CREATE TABLE categorie (
Idcat bigint(21) NOT NULL AUTO_INCREMENT,
Nomcat varchar(20) COLLATE utf8_unicode_ci NOT NULL,
PRIMARY KEY (Idcat, Nomcat)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;
Produits :
CREATE TABLE produits (
Codep bigint(21) NOT NULL AUTO_INCREMENT,
Reference bigint(21) NOT NULL,
Nomp varchar(20) COLLATE utf8_unicode_ci NOT NULL ,
Codef bigint(21) NOT NULL ,
Prenomf varchar(20) COLLATE utf8_unicode_ci NOT NULL,
Idcat bigint(21) NOT NULL ,
Nomcat varchar(20) COLLATE utf8_unicode_ci NOT NULL,
Description varchar(100) COLLATE utf8_unicode_ci NOT NULL,
PRIMARY KEY (Codep ),
FOREIGN KEY (Codef, Prenomf) REFERENCES fournisseurs (Codef, Prenomf)
ON DELETE CASCADE
ON UPDATE CASCADE ,
FOREIGN KEY (Idcat, Nomcat) REFERENCES categorie (Idcat, Nomcat)
ON DELETE CASCADE
ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci AUTO_INCREMENT=10;
I try to insert into Produits table as you see below :
exports.ajouterprod = function(req, res) {
console.log("req", req.body);
var today = new Date();
var produits = {
"Reference": req.body.Reference,
"Nomp": req.body.Nomp,
// "Codef": req.body.Codef,
"Prenomf": req.body.Prenomf,
//"Idcat": req.body.Idcat,
"Nomcat": req.body.Nomcat,
"Description": req.body.Description
}
connection.query('INSERT INTO produits SET ?', produits, function(error, results, fields) {
if (error) {
console.log("error ocurred", error);
res.send({
"code": 400,
"failed": "error ocurred"
})
}
else {
res.send({
"code": 200,
"success": "produit registered sucessfully"
});
}
})
};
when I run it with Postman, I get : "failed": "error ocurred"
and error ocurred { Error: ER_NO_DEFAULT_FOR_FIELD: Field 'Codef' doesn't have a default value on my backend.
As you see Codef is a primary key on my table fournisseurs.
How can I fix that ?

Answer 1

Why this error:
Since you are inserting data to Produits and not specifying any value Codef, this error is generated as foreign key needs a value(can be null as well)
Solution 1:
Alter table structure of Produits to have some default value that is either present in another table(where foreign key is referenced) or a null value.
Solution 2:
Add some default at code level and same in table where foreign key is referenced.