php pdo encapsulation class code (supports transactions)

/**
* PDO database
* @copyright By GOOGLE
*/
class pdo_db
{
/**
* PDO instance
* @var PDO
*/
protected $_db;
/**
* PDO prepared statement
* @var PDOStatement
*/
protected $_stmt;
/**
* Last SQL statement
* @var string
*/
protected $_sql;
/**
* Configuration information $config=array('dsn'=>xxx,'name'=>xxx,'password'=>xxx,'option'=>xxx)
* @var array
*/
protected $_config;
/**
* Constructor
* @param array $config
*/
public function __construct($config)
{
$this->_config = $config;
}
/**
* Connect to database
* @return void
*/
public function connect()
{
$this->_db = new PDO($this->_config['dsn'], $this->_config['name'], $this->_config['password'], $this->_config['option']);
//默认把结果序列化成stdClass
// $this->_db->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_OBJ);
$this->_db->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC);
//自己写代码捕获Exception
$this->_db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_SILENT);
}
/**
* Disconnect
* @return void
*/
public function disConnect()
{
$this->_db = null;
$this->_stmt = null;
}
/**
* Execute sql and return the newly added id
* @param string $statement
* @return string
*/
public function exec($statement)
{
if ($this->_db->exec($statement)){
$this->_sql = $statement;
return $this->lastId();
}
$this->errorMessage();
}
/**
* Query sql
* @param string $statement
* @return pdo_db
*/
public function query($statement)
{
$res = $this->_db->query($statement);
if ($res){
$this->_stmt = $res;
$this->_sql = $statement;
return $this;
}
$this->errorMessage();
}
/**
* Serialize data once
* @return mixed
*/
public function fetchOne()
{
return $this->_stmt->fetch();
}
/**
* Serialize all data
* @return array
*/
public function fetchAll()
{
return $this->_stmt->fetchAll();
}
/**
* Last added id
* @return string
*/
public function lastId()
{
return $this->_db->lastInsertId();
}
/**
* Number of rows affected
* @return int
*/
public function affectRows()
{
return $this->_stmt->rowCount();
}
/**
* prepared statement
* @param string $statement
* @return pdo_db
*/
public function prepare($statement)
{
$res = $this->_db->prepare($statement);
if ($res){
$this->_stmt = $res;
$this->_sql = $statement;
return $this;
}
$this->errorMessage();
}
/**
* Bind data
* @param array $array
* @return pdo_db
*/
public function bindArray($array)
{
foreach ($array as $k => $v){
if (is_array($v)){
//array的有效结构 array('value'=>xxx,'type'=>PDO::PARAM_XXX)
$this->_stmt->bindValue($k + 1, $v['value'], $v['type']);
} else{
$this->_stmt->bindValue($k + 1, $v, PDO::PARAM_STR);
}
}
return $this;
}
/**
* Execute prepared statements
* @return bool
*/
public function execute()
{
if ($this->_stmt->execute()){
return true;
}
$this->errorMessage();
}
/**
* Start transaction
* @return bool
*/
public function beginTransaction()
{
return $this->_db->beginTransaction();
}
/**
* Execute transaction
* @return bool
*/
public function commitTransaction()
{
return $this->_db->commit();
}
/**
* Rollback transaction
* @return bool
*/
public function rollbackTransaction()
{
return $this->_db->rollBack();
}
/**
* Throws Error
* @throws Error
* @return void
*/
public function errorMessage()
{
return;
$msg = $this->_db->errorInfo();
throw new Exception('数据库错误：' . $msg[2]);
}
//---------------------
/**
* Singleton instance
* @var pdo_db
*/
protected static $_instance;
/**
* Default database
* @static
* @param array $config
* @return pdo_db
*/
public static function instance($config)
{
if (!self::$_instance instanceof pdo_db){
self::$_instance = new pdo_db($config);
self::$_instance->connect();
}
return self::$_instance;
}
//----------------------
/**
* Get the database supported by PDO
* @static
* @return array
*/
public static function getSupportDriver(){
return PDO::getAvailableDrivers();
}
/**
* Get the version information of the database
* @return array
*/
public function getDriverVersion(){
$name = $this->_db->getAttribute(PDO::ATTR_DRIVER_NAME);
return array($name=>$this->_db->getAttribute(PDO::ATTR_CLIENT_VERSION));
}
}