PDO(PHP Data Object)学习

// 参数形式
$dsn = 'mysql:host=localhost;dbname=test';
$username = 'root';
$password = '';
$PDO = new PDO($dsn,$username,$password);

// URI形式
$dsn = 'uri:file://D:/newwamp/www/dsn.txt';
$username = 'root';
$password = '';
$PDO = new PDO($dsn,$username,$password);

// 配置文件形式
// 在php.ini 中配置 pdo.dsn.dsnConf="mysql:host=localhost;dbname=test"
$dsn = 'dsnConf';
$username = 'root';
$password = '';
$PDO = new PDO($dsn,$username,$password);

$PDO = new PDO('mysql:host=localhost;dbname=test','root','');
//直接执行PDO的query方法返回的是PDOStatement对象  PDOStatement 对象有fetch 和 fetchAll方法 返回数组
// 既可以在query方法返回的对象上调用这两个方法，也可以通过query方法链式调用

// 一 索引数组与关联数组并存
$stmt = $PDO->query("select id,name,phone from user"); // 返回一个PDOStatement类的对象
$data = $PDO->query("select id,name,phone from user")->fetch(); // 返回一条数据 array
$data = $PDO->query("select id,name,phone from user")->fetchAll(); // 返回所有数据 array
foreach($stmt as $k=>$v){
echo "<pre>";
print_r($v);
}
/*
以上程序的输出类似于
Array
(
[id] => 1
[0] => 1
[name] => king
[1] => king
[phone] => 13100000000
[2] => 13100000000
)
Array
(
[id] => 2
[0] => 2
[name] => queen
[1] => queen
[phone] => 13111111111
[2] => 13111111111
)
*/

// 二 只返回关联数组
$stmt = $PDO->query("select id,name,phone from user",PDO::FETCH_ASSOC);  // 返回一个PDOStatement类的对象
$data = $PDO->query("select id,name,phone from user",PDO::FETCH_ASSOC)->fetchAll();//array
$data = $PDO->query("select id,name,phone from user")->fetchAll(PDO::FETCH_ASSOC);// 效果同上
foreach($stmt as $k=>$v){
echo "<pre>";
print_r($v);
}
/*
以上程序的输出类似于
Array
(
[id] => 1
[name] => king
[phone] => 13100000000
)
Array
(
[id] => 2
[name] => queen
[phone] => 13111111111
)
*/

// 三 获取某一列 第三个参数为列的编号
$stmt = $PDO->query("select id,name,phone from user",PDO::FETCH_COLUMN,2);
foreach($stmt as $k=>$v){
echo "<pre>";
print_r($v);
}
/*
以上程序的输出类似于
13100000000
13111111111
*/

// 四 取出的每个数据为某个类的对象返回 其中类的构造函数和query的第四个参数同时存在或同时不存在
//    取出的每一条数据都以myobj的一个实例对象返回 取出的字段名都作为对象的属性，值作为对象的属性值存在
class myobj{
private $lei;
public function __construct($lei){
$this->lei = $lei;
}
}

$data = $PDO->query(
"select id,name,phone from user",
PDO::FETCH_CLASS,
'myobj',
array('lei'=>'dog')
)->fetchAll();

foreach($data as $k=>$v){
echo "<pre>";
print_r($v);
}
/*
以上程序输出类似于
myobj Object
(
[lei:myobj:private] => dog
[id] => 1
[name] => king
[phone] => 13100000000
)
myobj Object
(
[lei:myobj:private] => dog
[id] => 2
[name] => queen
[phone] => 13111111111
)
*/

$sql = "select * from user";
$stmt = $PDO->prepare($sql);
$res = $stmt->execute();
// 第一种方式 fetchAll设置参数取数据
//  if($res){
//      $rows = $stmt->fetchAll(PDO::FETCH_ASSOC);
//      var_dump($rows);
//  }
// 第二种方式 setFetchMode方法取数据
if($res){
$stmt->setFetchMode(PDO::FETCH_NUM);
$rows1 = $stmt->fetchAll();
var_dump($rows1);
}

<?php
if ($db->getAttribute(PDO::ATTR_DRIVER_NAME) == 'mysql') {
echo "Running on mysql; doing something mysql specific here\n";
}
?>

<span style="font-size:18px;">$PDO->getAttribute(<span style="color: rgb(51, 51, 51); font-family: "Open Sans", "Helvetica Neue", Helvetica, Arial, STHeiti, "Microsoft Yahei", sans-serif; background-color: rgb(246, 244, 240);">PDO::ATTR_AUTOCOMMIT</span>);
$PDO->setAttribute(<span style="color: rgb(51, 51, 51); font-family: "Open Sans", "Helvetica Neue", Helvetica, Arial, STHeiti, "Microsoft Yahei", sans-serif; background-color: rgb(246, 244, 240);">PDO::ATTR_AUTOCOMMIT,1</span>);</span>

$dsn = 'mysql:host=localhost;dbname=test';
$username = 'root';
$password = '';
$options = array(
PDO::ATTR_AUTOCOMMIT=>1
);
$PDO = new PDO($dsn,$username,$password,$options);

$username = "king'queen";
$username1 = $PDO->quote($username);
echo $username;
echo "<br/>";
echo $username1;
// king'queen         输出结果为
// 'king\'queen'

// 预处理中的参数占位形式
$username = 'ceshi';
$passwd = '123456';
$sql = " select * from user where username = :username and passwd = :passwd";
$stmt = $PDO->prepare($sql);
$stmt->execute(array(':username'=>$username,':passwd'=>$passwd));
$result = $stmt->fetchAll(PDO::FETCH_ASSOC);
var_dump($result);
/*array (size=1)    // 以上程序输出类似
0 =>
array (size=5)
'id' => string '1' (length=1)
'phone' => string '13100000000' (length=11)
'username' => string 'ceshi' (length=5)
'passwd' => string '123456' (length=6)
'email' => string 'ceshi@qq.com' (length=12)*/

// 预处理中的 ? 形式
$username = 'ceshi';
$passwd = '123456';
$sql = " select * from user where username = ? and passwd = ?";
$stmt = $PDO->prepare($sql);
$stmt->execute(array($username,$passwd));
$result = $stmt->fetchAll(PDO::FETCH_ASSOC);
var_dump($result);
// 以上程序输出类似
/*array (size=1)
0 =>
array (size=5)
'id' => string '1' (length=1)
'phone' => string '13100000000' (length=11)
'username' => string 'ceshi' (length=5)
'passwd' => string '123456' (length=6)
'email' => string 'ceshi@qq.com' (length=12)*/

// bindParam方法的使用
$sql = "select * from user where phone = :phone";
$stmt = $PDO->prepare($sql);
$stmt->bindParam(":phone",$phone,PDO::PARAM_STR);
$phone = '13100000000'; // 可能通过GET 或 POST 接收
$stmt->execute();
$stmt->setFetchMode(PDO::FETCH_ASSOC);
$arr = $stmt->fetchAll();
echo "<pre>";
var_dump($arr);
// 以上程序输出类似  适用于增删改查
/*array(1) {
[0]=>
array(3) {
["id"]=>
string(1) "1"
["name"]=>
string(4) "king"
["phone"]=>
string(11) "13100000000"
}
}*/

// bindValue 方法的使用
$sql = "select * from user where phone = :phone";
$stmt = $PDO->prepare($sql);
$stmt->bindValue(":phone",'13100000000'); // 此处可直接写值并且绑定一次可多次使用

$stmt->execute();
$stmt->setFetchMode(PDO::FETCH_ASSOC);
$arr = $stmt->fetchAll();
echo "<pre>";
var_dump($arr);
// 以上程序输出类似
/*array(1) {
[0]=>
array(3) {
["id"]=>
string(1) "1"
["name"]=>
string(4) "king"
["phone"]=>
string(11) "13100000000"
}
}*/