简易封装PDO的操作类

<?php
ini_set('display_errors', true);

final class DB {
    private static $db;
    public static function getInstance(): PDO {
        if(!self::$db instanceof PDO) {
            new self();
        }
        return self::$db;
    }
    private function __clone() {}
    private function __construct() {
        $config = parse_ini_file('./db.ini');
        $dsn = sprintf('mysql:localhost=%s;dbname=%s;port=%d;charset=%s', $config['host'], $config['dbname'], $config['port'], $config['charset']);
        try{
            self::$db = new PDO($dsn, $config['user'], $config['password']);
        }catch(PDOException $e) {
            exit($e->getMessage());
        }
    }
}

class Statement {
    private static $statement;
    private $state;
    private function __construct(PDO $db, string $sql) {
        $this->state = $db->prepare($sql);
    }
    public static function getInstance(PDO $db, string $sql) {
        if(!self::$statement instanceof Statement) {
            self::$statement = new self($db, $sql);
        }
        return self::$statement;
    }
    public function bindValue($key, $val) {
        return $this->state->bindValue($key, $val);
    }
    public function bindParam($key, $val) {
        return $this->state->bindParam($key, $val);
    }
    public function execute() {
        return $this->state->execute();
    }
    public function fetchOne() {
        return $this->state->fetch(PDO::FETCH_ASSOC);
    }
    public function fetchAll() {
        return $this->state->fetchAll(PDO::FETCH_ASSOC);
    }
    public function fetchColumn(int $index = null) {
        return $this->state->fetchColumn($index);
    }
    public function resetQuery() {
        return $this->state->closeCursor();
    }
    public function effectRow() {
        return $this->state->rowCount();
    }
    public function errorReason() {
        return $this->state->errorInfo()[2];
    }
}

/**建立方法的抽象基类
 * Class Base
 */
abstract class Base {
    protected $db;
    protected $statement;
    public function __construct(string $sql) {
        $this->db = DB::getInstance();
        $this->statement = Statement::getInstance($this->db, $sql);
    }
    protected function exec() {
        return $this->statement->execute() ? true: $this->statement->errorReason() ?? 'SQL语句有误';
    }

    public function bindValue($key = null, $val = null) {
        if(func_num_args() === 0 || (!is_array($key) && !$val)) {
            return $this;
        } else if(is_array($key)) {
            foreach($key as $k => $v) {
                $this->statement->bindValue($k, $v);
            }
        } else {
            $this->statement->bindValue($key, $val);
        }
        return $this;
    }
    public function bindParam($key = null, $val = null) {
        if(func_num_args() === 0 || (!is_array($key) && !$val)) {
            return $this;
        } else if(is_array($key)) {
            foreach($key as $k => $v) {
                $this->statement->bindParam($k, $v);
            }
        } else {
            $this->statement->bindParam($key, $val);
        }
        return $this;
    }
    public static function getDB(): PDO {
        return DB::getInstance();
    }
}

class Query extends Base{
    private function queryRes(bool $is_all = false) {
        $res = $this->exec();
        if($res === true) {
            $data = $is_all? $this->statement->fetchAll(): $this->statement->fetchOne();
            return $data === false? []: $data;
        }
        return $res;
    }
    public function one() {
        return $this->queryRes(false);
    }
    public function all() {
        return $this->queryRes(true);
    }
    public function fetchColumn($index = 0) {
        $res = $this->exec();
        if($res) {
            $data = $this->statement->fetchColumn($index);
            return $data === false? '': $data;
        }
        return $res;
    }
    public function __destruct() {
        $this->statement->resetQuery();
    }
}

class Operate extends Base{
    public function execute() {
        $res = $this->exec();
        if($res === true) {
            return $this->statement->effectRow();
        }
        throw new PDOException($res);
    }

    public static function beginTransaction($fn) {
        if(!$fn) {
            return false;
        }
        self::getDB()->beginTransaction();
        try{
            call_user_func($fn);
            return self::getDB()->commit()? true: false;
        }catch(PDOException $e) {
            self::getDB()->rollBack();
            throw $e;
        }
    }
    //注意：如果在事务中进行调用，那么就有可能获取不到
    public static function lastInsertId() {
        return self::getDB()->lastInsertId();
    }
}

//$res = (new Query('SELECT `u`.`user`, `temp`.`pwd` FROM `user` AS `u` LEFT JOIN (SELECT `id`, `pwd` FROM `user`) AS `temp` ON `temp`.`id` = `u`.`id` WHERE `u`.`id` > :id'))->bindValue(':id', 3)->all();
//var_dump($res);
//$res = (new Query('SELECT * FROM `user`'))->all();
//var_dump($res);
//$res = (new Operate('UPDATE `user` SET `user` = :user WHERE `id` = :id'))->bindValue([
//    ':user' => 'are you ok???',
//    ':id' => 1
//])->execute();
//var_dump($res);

//Operate::getDB()->beginTransaction();
//try{
//    $res1 = (new Operate('UPDATE `user` SET `user` = :user WHERE `id` = :id'))->bindValue([
//        ':user' => 'tt',
//        ':id' => 1
//    ])->execute();
//    $res2 = (new Operate('UPDATE `user` SET `user` = :user WHERE `id` = :id'))->bindValue([
//        ':user' => 'tt',
//        ':id' => 2
//    ])->execute();
//    if($res1 === true && $res2 === true) {
//        Operate::getDB()->commit();
//    }
//}catch(PDOException $e) {
//    Operate::getDB()->rollBack();
//    throw $e;
//}

//$res1 = (new Operate('UPDATE `user` SET `user` = :user WHERE `id` = :id'))->bindValue([
//    ':user' => 'tt',
//    ':id' => 1
//])->execute();
//$res2 = (new Operate('UPDATE `user` SET `user` = :user WHERE `id` = :id'))->bindValue([
//    ':user' => 'tt',
//    ':id' => 2
//])->execute();
//var_dump($res1);
//var_dump($res2);

//$res = Operate::beginTransaction(function() {
//    (new Operate('INSERT INTO `user` (`user`, `pwd`) VALUES (:user, :pwd)'))->bindValue([
//        ':user' => 'wakaka',
//        ':pwd' => 'nono'
//    ])->execute();
//});
//var_dump($res);

(new Operate('INSERT INTO `user` (`user`, `pwd`) VALUES (:user, :pwd)'))->bindValue([
    ':user' => 'wakaka',
    ':pwd' => 'nono'
])->execute();
var_dump(Operate::lastInsertId());
?>