这是Vote it Up 插件：

//Run this to create an entry for a post in the voting system. Will check if the post exists. If it doesn\'t, it will create an entry.
function SetPost($post_ID) {
    global $wpdb;

    //prevents SQL injection
    $p_ID = $wpdb->escape($post_ID);

    //Check if entry exists
    $id_raw = $wpdb->get_var("SELECT ID FROM ".$wpdb->prefix."votes WHERE post=\'".$p_ID."\'");
    if ($id_raw != \'\') {
        //entry exists, do nothing
    } else {
        //entry does not exist
        $wpdb->query("INSERT INTO ".$wpdb->prefix."votes (post, votes, guests, usersinks, guestsinks) VALUES(".$p_ID.", \'\', \'\', \'\', \'\') ") or die(mysql_error());
    }
}

//Run this to create an entry for a user in the voting system. Will check if the user exists. If it doesn\'t, it will create an entry.
function SetUser($user_ID) {
    global $wpdb;

    //prevents SQL injection
    $u_ID = $wpdb->escape($user_ID);

    //Check if entry exists
    $id_raw = $wpdb->get_var("SELECT ID FROM ".$wpdb->prefix."votes_users WHERE user=\'".$u_ID."\'");
    if ($id_raw != \'\') {
        //entry exists, do nothing
    } else {
        //entry does not exist
        $wpdb->query("INSERT INTO ".$wpdb->prefix."votes_users (user, votes, sinks) VALUES(".$u_ID.", \'\', \'\') ") or die(mysql_error());
    }
}

//Returns the vote count
function GetVotes($post_ID, $percent = false) {
    global $wpdb;

    //prevents SQL injection
    $p_ID = $wpdb->escape($post_ID);

    //Create entries if not existant
    SetPost($p_ID);

    //Gets the votes
    $votes_raw = $wpdb->get_var("SELECT votes FROM  ".$wpdb->prefix."votes WHERE post=\'".$p_ID."\'");
    $sinks_raw = $wpdb->get_var("SELECT usersinks FROM  ".$wpdb->prefix."votes WHERE post=\'".$p_ID."\'");
    $guestvotes_raw = $wpdb->get_var("SELECT guests FROM  ".$wpdb->prefix."votes WHERE post=\'".$p_ID."\'");
    $guestsinks_raw = $wpdb->get_var("SELECT guestsinks FROM  ".$wpdb->prefix."votes WHERE post=\'".$p_ID."\'");
/* Deprecated
    $uservotes_raw = $wpdb->get_var("SELECT votes FROM ".$wpdb->prefix."votes_users WHERE user=\'".$u_ID."\'");
    $usersinks_raw = $wpdb->get_var("SELECT sinks FROM ".$wpdb->prefix."votes_users WHERE user=\'".$u_ID."\'");
*/

    //Put it in array form
    $votes = explode(",", $votes_raw);
    $sinks = explode(",", $sinks_raw);
    $guestvotes = explode(",", $guestvotes_raw);
    $guestsinks = explode(",", $guestsinks_raw);
/* Deprecated
    $uservotes = explode(",", $uservotes_raw);
    $usersinks = explode(",", $usersinks_raw);
*/
    $uservotes = 0;
    $usersinks = 0;

    $initial = 0; //Initial no. of votes [will be placed at -1 when all posts receive votes]

我从许多人那里听说，直接访问mysql数据库是一种不好的做法。这些代码可能会在未来版本的Wordpress中分解。

或者它在一些插件中是必要的，比如投票？