Wordpress- prevent duplication of custom field value

Question

I want to check values of meta-key called cf_isbn already in database in table wp-postmeta. If value is repeated, prevent insert content.

I have piece of code, that works correctly if I put xxxxxxx value to my ISBN field in frontend post-input, but the main point is change xxxxxxx with query to check values already exist in database.

Is there any php wizard who know how to help me?

function wpufe_isbn_validation( $errors ) {
    if( $_POST['cf_isbn'] == 'xxxxxxx' ) {
        $errors[] = 'this ISBN is already in database';
    }

    return $errors;
}
add_filter( 'wpuf_add_post_validation', 'wpufe_isbn_validation' );

score 0 · Accepted Answer · answered May 19 '15 at 08:49

0

You should be able to do something like so:

function wpufe_isbn_validation( $errors )
{
    global $wpdb;
    $check = $wpdb->query( $wpdb->prepare("
    SELECT *
    FROM wp-postmeta
    WHERE meta_key = cf_isbn AND meta_value = ".$_POST['cf_isbn']) );


    if(!empty($check))
    {
       return true;
    }
    else
    {
       return false;
    }
}
add_filter( 'wpuf_add_post_validation', 'wpufe_isbn_validation' );

Then you can simply execute another function/piece of code depending on what is returned. Obviously if the above returns true, then the ISBN is duplicated and does not need to be inserted.

answered May 19 '15 at 08:49

The Humble Rat

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Great, but it was not working. I still can add ISBN that already exist in database ;/ – Kamil Pilawka May 19 '15 at 13:24
Ołłłł yeah! I edited just this: $check = $wpdb->query( $wpdb->prepare("SELECT * FROM `wp_postmeta` WHERE `meta_key` LIKE 'cf_isbn' AND `meta_value` = ".$_POST['cf_isbn']) ); and now works correctly :D – Kamil Pilawka May 19 '15 at 13:37
But there is another problem- it was working only for 'xxxxxxxxxxx' values, not for 'xx-xxx-xxx'. Now I need rebuild function, or delete all "-" value in my table, but only with "meta_key = cf_isbn". Any sugestions? – Kamil Pilawka May 19 '15 at 13:49
Sory for spamming, but well done. by this UPDATE `wp_postmeta` SET meta_value = replace(meta_value, '-', '') WHERE meta_key LIKE 'cf_isbn' – Kamil Pilawka May 19 '15 at 14:36
@KamilPilawka accept the answer if it works for you. – The Humble Rat May 19 '15 at 14:40

Wordpress- prevent duplication of custom field value

1 Answers1