duplicate key is still inserting as an entry in MYSQL

Question

It just keeps adding a row even if it already exists and i don't get why?

$submitted = explode("@", $submit['tag']);
foreach ($submitted as $tag => $value) {
    if ($value != "") {
        $attag = "@".$value;
        $sql_insert = dbquery("INSERT INTO dbtags(tag_name, tag_txt) VALUES('$value', '$attag') ON DUPLICATE KEY UPDATE tag_name=tag_name");
    }
}

Can anyone help?

Answer 1

You sure you mean UPDATE tag_name=tag_name and not UPDATE tag_name=$value ?

Also, use PDO.

Answer 2

It should be Unique other wise duplicate will not work . On DUPLICATE KEY UPDATE tag_name=tag_name") change to On DUPLICATE KEY IGNORE

Answer 3

change tag_name data type to Binary, you may be facing problem of case-sensitiveness