Detailed explanation of php mysql connection method pdo usage

$dbh = new PDO('mysql:host=localhost;dbname=access_control', 'root', '');
$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$dbh->exec('set names utf8');
/*添加*/
//$sql = "INSERT INTO `user` SET `login`=:login AND `password`=:password";
$sql = "INSERT INTO `user` (`login` ,`password`)VALUES (:login, :password)";  $stmt = $dbh->prepare($sql);  $stmt->execute(array(':login'=>'kevin2',':password'=>''));
echo $dbh->lastinsertid();
/*修改*/
$sql = "UPDATE `user` SET `password`=:password WHERE `user_id`=:userId";
$stmt = $dbh->prepare($sql);
$stmt->execute(array(':userId'=>'7', ':password'=>'4607e782c4d86fd5364d7e4508bb10d9'));
echo $stmt->rowCount();
/*删除*/
$sql = "DELETE FROM `user` WHERE `login` LIKE 'kevin_'"; //kevin%
$stmt = $dbh->prepare($sql);
$stmt->execute();
echo $stmt->rowCount();
/*查询*/
$login = 'kevin%';
$sql = "SELECT * FROM `user` WHERE `login` LIKE :login";
$stmt = $dbh->prepare($sql);
$stmt->execute(array(':login'=>$login));
while($row = $stmt->fetch(PDO::FETCH_ASSOC)){
 print_r($row);
}
print_r( $stmt->fetchAll(PDO::FETCH_ASSOC));
?>

1、建立连接

 $dbh=newPDO('mysql:host=localhost;port=3306; dbname=test',$user,$pass,array(
 PDO::ATTR_PERSISTENT=>true
 ));
 ?>

持久性链接PDO::ATTR_PERSISTENT=>true

2，捕捉错误

 try{
 $dbh=newPDO('mysql:host=localhost;dbname=test',$user,$pass);
 $dbh->setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_EXCEPTION);
 $dbh->exec("SET CHARACTER SET utf8");
 $dbh=null; //断开连接
 }catch(PDOException$e){
 print"Error!:".$e->getMessage()."";
 die();
 }
?>

3，pdo事务

try{
$dbh->setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_EXCEPTION);
$dbh->beginTransaction();//开启事务
$dbh->exec("insertintostaff(id,first,last)values(23,'Joe','Bloggs')");
$dbh->exec("insertintosalarychange(id,amount,changedate)
values(23,50000,NOW())");
$dbh->commit();//提交事务
}catch(Exception$e){
$dbh->rollBack();//错误回滚
echo"Failed:".$e->getMessage();
}
?>

4. 错误处理 a. 静默模式(默认模式)

 try{
  $dbh = new PDO($dsn, $user, $password);
  $sql = 'Select * from city where CountryCode =:country';
  $dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_WARNING);
  $stmt = $dbh->prepare($sql);
  $stmt->bindParam(':country', $country, PDO::PARAM_STR);
  $stmt->execute();
  while ($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
   print $row['Name'] . "/t";
  }
 }   // if there is a problem we can handle it here
 catch (PDOException $e)  {
  echo 'PDO Exception Caught.  ';
  echo 'Error with the database: ';
  echo 'SQL Query: ', $sql;
  echo 'Error: ' . $e->getMessage();
 }
 ?>

1，使用 query()

$dbh->query($sql); 当$sql 中变量可以用$dbh->quote($params); //转义字符串的数据
$sql = 'Select * from city where CountryCode ='.$dbh->quote($country);
foreach ($dbh->query($sql) as $row)   {
 print $row['Name'] . "/t";
 print $row['CountryCode'] . "/t";
 print $row['Population'] . "/n";
}
?>

2, use prepare, bindParam and execute [recommended, you can also add, modify, delete]

$dbh->prepare($sql); generates a PDOStatement object
PDOStatement->bindParam()
PDOStatement->execute();//You can put it here The corresponding bound variables
?>

3. PHP pdo transaction example

 try {
 $dbh = new PDO('mysql:host=localhost;dbname=test', 'root', '');
 $dbh->query('set names utf8;');
 $dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
 $dbh->beginTransaction();
 $dbh->exec("Insert INTO `test`. `table` (`name` ,`age`)VALUES ('mick', 22);");
 $dbh->exec("Insert INTO `test`.`table` (`name` ,`age` )VALUES ('lily', 29);");
 $dbh->exec("Insert INTO `test`.`table` (`name` ,`age`)VALUES ('susan', 21);" );
 $dbh->commit();
 } catch (Exception $e) {
 $dbh->rollBack();
 echo "Failed: " . $e->getMessage();
 }
 ?>