PDO封装mysql

<?php

class mysqlPDO
{

    protected static $_instance = null;
    protected $dbName = '';
    protected $dsn;
    protected $dbh;

    //构造
    private function __construct($dbHost, $dbUser, $dbPasswd, $dbName, $dbCharset)
    {
        try {
            $this->dsn = 'mysql:host='.$dbHost.';dbname='.$dbName;
            $this->dbh = new PDO($this->dsn, $dbUser, $dbPasswd);
            $this->dbh->exec('SET character_set_connection='.$dbCharset.', character_set_results='.$dbCharset.', character_set_client=binary');
        } catch (PDOException $e) {
            $this->outputError($e->getMessage());
        }
    }

    //防止克隆
    private function __clone() {}

    public static function getInstance($dbHost, $dbUser, $dbPasswd, $dbName, $dbCharset)
    {
        if (self::$_instance === null) {
            self::$_instance = new self($dbHost, $dbUser, $dbPasswd, $dbName, $dbCharset);
        }
        return self::$_instance;
    }

    //执行
    public function query($strSql, $queryMode = 'All', $debug = false)
    {
        if ($debug === true) $this->debug($strSql);
        $recordset = $this->dbh->query($strSql);
        $this->getPDOError();
        if ($recordset) {
            $recordset->setFetchMode(PDO::FETCH_ASSOC);
            if ($queryMode == 'All') {
                $result = $recordset->fetchAll();
            } elseif ($queryMode == 'Row') {
                $result = $recordset->fetch();
            }
        } else {
            $result = null;
        }
        return $result;
    }

    //修改
    public function update($table, $arrayDataValue, $where = '', $debug = false)
    {
        $this->checkFields($table, $arrayDataValue);
        if ($where) {
            $strSql = '';
            foreach ($arrayDataValue as $key => $value) {
                $strSql .= ", `$key`='$value'";
            }
            $strSql = substr($strSql, 1);
            $strSql = "UPDATE `$table` SET $strSql WHERE $where";
        } else {
            $strSql = "REPLACE INTO `$table` (`".implode('`,`', array_keys($arrayDataValue))."`) VALUES ('".implode("','", $arrayDataValue)."')";
        }
        if ($debug === true) $this->debug($strSql);
        $result = $this->dbh->exec($strSql);
        $this->getPDOError();
        return $result;
    }

    //批量插入
    public function batchInsert($table,$arrayDatakay, $arrayDataValue, $debug = false)
    {
        $this->checkFields($table, $arrayDatakay);
        $arrayDataValue = array_values($arrayDataValue);
        $sql_val = '';
        foreach ($arrayDataValue as $key=>$val){
            if($key!=0 && !empty($val))
            {
                $sql_val .=',';
            }
            $sql_val .= '("'.implode('","', $val).'")';
        }
        $strSql = "INSERT INTO `$table` (`".implode('`,`', array_keys($arrayDatakay))."`) VALUES $sql_val";
        if ($debug === true) $this->debug($strSql);
        $result = $this->dbh->exec($strSql);
        $this->getPDOError();
        return $result;
    }

    //插入
    public function insert($table, $arrayDataValue, $debug = false)
    {
        $this->checkFields($table, $arrayDataValue);
        $strSql = "INSERT INTO `$table` (`".implode('`,`', array_keys($arrayDataValue))."`) VALUES ('".implode("','", $arrayDataValue)."')";
        if ($debug === true) $this->debug($strSql);
        $this->dbh->exec($strSql);
        $this->getPDOError();
        $result =  $this->dbh->lastInsertId();
        return $result;
    }

    //删除
    public function delete($table, $where = '', $debug = false)
    {
        if ($where == '') {
            $this->outputError("'WHERE' is Null");
        } else {
            $strSql = "DELETE FROM `$table` WHERE $where";
            if ($debug === true) $this->debug($strSql);
            $result = $this->dbh->exec($strSql);
            $this->getPDOError();
            return $result;
        }
    }

    //执行sql语句
    public function execSql($strSql, $debug = false)
    {
        if ($debug === true) $this->debug($strSql);
        $result = $this->dbh->exec($strSql);
        $this->getPDOError();
        return $result;
    }

    //预处理执行
    public function prepareSql($sql=''){
        return $this->dbh->prepare($sql);
    }

    //执行预处理
    public function execute($presql){
        return $this->dbh->execute($presql);
    }

    //事务开始
    public function beginTransaction()
    {
        $this->dbh->beginTransaction();
    }

    //事务提交
    public function commit()
    {
        $this->dbh->commit();
    }

    //事务回滚
    public function rollback()
    {
        $this->dbh->rollback();
    }

    //检查指定字段是否在指定数据表中存在
    private function checkFields($table, $arrayFields)
    {
        $fields = $this->getFields($table);
        foreach ($arrayFields as $key => $value) {
            if (!in_array($key, $fields)) {
                $this->outputError("Unknown column `$key` in field list.");
            }
        }
    }

    //获取指定数据表中的全部字段名
    private function getFields($table)
    {
        $fields = array();
        $recordset = $this->dbh->query("SHOW COLUMNS FROM $table");
        $this->getPDOError();
        $recordset->setFetchMode(PDO::FETCH_ASSOC);
        $result = $recordset->fetchAll();
        foreach ($result as $rows) {
            $fields[] = $rows['Field'];
        }
        return $fields;
    }

    //捕获PDO错误信息
    private function getPDOError()
    {
        if ($this->dbh->errorCode() != '00000') {
            $arrayError = $this->dbh->errorInfo();
            $this->outputError($arrayError[2]);
        }
    }

    //debug
    private function debug($debuginfo)
    {
        var_dump($debuginfo);
        exit();
    }

    //输出错误信息
    private function outputError($strErrMsg)
    {
        throw new Exception('MySQL Error: '.$strErrMsg);
    }

    //关闭数据库连接
    public function destruct()
    {
        $this->dbh = null;
    }

    //PDO执行sql语句,返回改变的条数
    public function exec($sql='')
    {
        return $this->dbh->exec($sql);
    }

}