Quick and dirty email signup in php and sqlite

EmailSignup.php

<?php

class EmailSignup {

    private $db;

    // defaults can be overwritten on instantiation
    private $filename = "emailsignups.sqlite";
    private $tablename = "emails";

    function __construct($filename = '', $tablename = ''){

        // Check for changed filename or tablename
        if($filename != '') $this->filename = $filename;
        if($tablename != '') $this->tablename = $tablename;

        // instantiate sqlite connection
        if ($db = new SQLiteDatabase($this->filename)) {

            // Check for existing table
            $sql = "SELECT name FROM sqlite_master WHERE type='table' AND name='".$this->tablename."'";
            $query = $db->query($sql);

            // Create email table if it doesn't exist
            if(!$result = $query->numRows()){

                $sql = "CREATE TABLE ".$this->tablename." (email CHAR(255) PRIMARY KEY, name CHAR(255), created DATETIME)";
                $query = $db->query($sql);
            }

            // Set instance database connection
            $this->db = $db;
        }
    }

    function subscribe($email,$name=""){

        $sql = 'INSERT INTO '.$this->tablename.' VALUES ("'.$email.'","'.$name.'", DATETIME("now"))';
        $query = @$this->db->queryExec($sql,$error);
        if($query) {
           return true;
        }

        return $rtn;
    }

    function unsubscribe($email){
        $sql = 'DELETE FROM '.$this->tablename.' WHERE email="'.$email.'" LIMIT 1';
        $query = $this->db->queryExec($sql,$error);
        if($query){
            return true;
        }
        return false;
    }

    function getList(){
        $sql = 'SELECT * FROM '.$this->tablename;
        $query = $this->db->query($sql);
        $result = $query->fetchAll(SQLITE_ASSOC);
        return $result;
    }

    function getByEmail($email){

        $sql = 'SELECT * FROM '.$this->tablename.' WHERE email = "'.$email.'"';
        $query = $this->db->query($sql);
        if($query->numRows() > 0){
            return $query->fetchAll(SQLITE_ASSOC);
        }

        return false;
    }

    function formatName($name){ return trim($name); }
    function formatEmail($email){ return strtolower(trim($email)); }

    /**
     * Uber validation method found at:
     * http://www.linuxjournal.com/article/9585?page=0,3
     *
     */
    function validEmail($email, $checkDNS=false) {
        $isValid = true;
        $atIndex = strrpos($email, "@");
        if (is_bool($atIndex) && !$atIndex) {
            $isValid = false;
        } else {
            $domain = substr($email, $atIndex+1);
            $local = substr($email, 0, $atIndex);
            $localLen = strlen($local);
            $domainLen = strlen($domain);
            if ($localLen < 1 || $localLen > 64) {
                // local part length exceeded
                $isValid = false;
            } else if ($domainLen < 1 || $domainLen > 255) {
                // domain part length exceeded
                $isValid = false;
            } else if ($local[0] == '.' || $local[$localLen-1] == '.') {
                // local part starts or ends with '.'
                $isValid = false;
            } else if (preg_match('/\\.\\./', $local)) {
                // local part has two consecutive dots
                $isValid = false;
            } else if (!preg_match('/^[A-Za-z0-9\\-\\.]+$/', $domain)) {
                // character not valid in domain part
                $isValid = false;
            } else if (preg_match('/\\.\\./', $domain)) {
                // domain part has two consecutive dots
                $isValid = false;
            } else if (!preg_match('/^(\\\\.|[A-Za-z0-9!#%&`_=\\/$\'*+?^{}|~.-])+$/', str_replace("\\\\","",$local))) {
                // character not valid in local part unless
                // local part is quoted
                if (!preg_match('/^"(\\\\"|[^"])+"$/', str_replace("\\\\","",$local))) {
                    $isValid = false;
                }
            }

            if($checkDNS) {
                if ($isValid && !(checkdnsrr($domain,"MX") || checkdnsrr($domain,"A"))) {
                    //domain not found in DNS
                    $isValid = false;
                }
            }
        }
        return $isValid;
    }

}
?>