I have the following code that registers in the database the id of an article that the user liked.
$sql = "INSERT INTO favoritos (id_user, id_oferta)
VALUES ('$login_session', '$id')";
if ($conn->query($sql) === TRUE) {
echo "New record created successfully";
} else {
echo "Error: " . $sql . "<br>" . $conn->error;
}
As I have the code, the user can like the same article as often as he likes.
How can I resolve this situation?
does the search for this favorite and if it exists do not insert it.
$sql = "select * from favoritos where id_user=? and id_oferta=? limit 1"
$stmt=$conn->prepare($sql);
$stmt->excute(array($login_session,$id));
$result= $stmt->fetch(PDO::FETCH_ASSOC)
if($result != false){ //ja existe
// ..insere no banco
}
Another solution to not having to make two requests in the database is to do an insert with select :
INSERT INTO
favoritos (id_user, id_oferta)
SELECT
('$login_session', '$id')
WHERE
NOT EXISTS( SELECT 1 FROM favoritos WHERE id_user = '$login_session' AND id_oferta = '$id')
I would use ON DUPLICATE KEY . You can read more at DOC . The advantage is having a single query for insert and update .
INSERT INTO favoritos( id_user, id_oferta )
VALUES( $login_session, $id )
ON DUPLICATE KEY UPDATE id_user = $login_session, id_oferta = $id
If someone has a similar problem, my code is as follows:
//verifica se já existe
$query = mysql_query("select * from favoritos where id_user='$login_session' AND id_oferta='$id'", $connection);
$rows = mysql_num_rows($query);
if ($rows != false) {
echo "ja existe";
} else {
//Faz o que eu quero :p
}