Css位置保存在数据库中

Question

I have a question. I am building a multi themed site, I have stored the css locations in users database under theme. The problem is trying to get the .css file location in the href of the .tpl (template file) to allow it to work right. If there is anyway possible to get the the href to read a database?

This is my code in my class_user.php

/* ------------------------------- */
/* themes */
/* ------------------------------- */

/**
 * get_user_theme_ids
 * 
 * @return array
 */
public function get_user_theme_ids() {
    global $db;
    $themes = array();
    $get_themes = $db->query("SELECT user_id FROM users") or _error(SQL_ERROR_THROWEN);
    if($get_themes->num_rows > 0) {
        while($theme = $get_themes->fetch_assoc()) {
            $themes[] = $theme['user_id'];
        }
    }
    return $themes;
}


/**
 * get_theme_location
 * 
 * @return array
 */
public function get_themes_location() {
    global $db;
    $themes = array();
    $get_themes = $db->query("SELECT * FROM users") or _error(SQL_ERROR_THROWEN);
    if($get_themes->num_rows > 0) {
        while($theme = $get_themes->fetch_assoc()) {
            $theme['theme_location'] = get_url_text($theme['theme_id']);
            $themes[] = $theme;
        }
    }
    return $themes;
}

Now in my head.tpl I have

<link rel="stylesheet" type='text/css' href="{$theme['theme_id']}" />

it will not input the text from the database into the href. What am i doing wrong?