pdo连接mysql数据库(简洁明了)

一实例化pdo对象

$dsn = "mysql:dbname=test;host=127.0.0.1";
$pdo = new PDO($dsn,'root','root');

二数据查询

1、如果不根据用户传过来的值进行操作,可以直接query sql

$dsn = "mysql:dbname=test;host=127.0.0.1";
$pdo = new PDO($dsn,'root','root');
$sql = "select * from student";
$stmt = $pdo->query($sql);
var_dump($stmt->fetchAll(2));

数据是可以正常显示的

array (size=39)0 => array (size=8)'id' =>  '1' (length=1)'name' =>  '周更生' (length=9)'sex' =>  '男' (length=3)'age' =>  '24' (length=2)'edu' =>  '大专' (length=6)'salary' =>  '5000.00' (length=7)'bonus' =>  '200.00' (length=6)'city' =>  '山东省' (length=9)1 => array (size=8)'id' =>  '2' (length=1)'name' =>  '王小平' (length=9)'sex' =>  '男' (length=3)'age' =>  '28' (length=2)'edu' =>  '大专' (length=6)'salary' =>  '500.00' (length=6)'bonus' =>  '200.00' (length=6)'city' =>  '陕西省' (length=9)2 => array (size=8)'id' =>  '3' (length=1)'name' =>  '周改娟' (length=9)'sex' =>  '女' (length=3)'age' =>  '28' (length=2)'edu' =>  '大专' (length=6)'salary' =>  '8000.00' (length=7)... (size=39)0 => array (size=8)'id' =>  '1' (length=1)'name' =>  '周更生' (length=9)'sex' =>  '男' (length=3)'age' =>  '24' (length=2)'edu' =>  '大专' (length=6)'salary' =>  '5000.00' (length=7)'bonus' =>  '200.00' (length=6)'city' =>  '山东省' (length=9)1 => array (size=8)'id' =>  '2' (length=1)'name' =>  '王小平' (length=9)'sex' =>  '男' (length=3)'age' =>  '28' (length=2)'edu' =>  '大专' (length=6)'salary' =>  '500.00' (length=6)'bonus' =>  '200.00' (length=6)'city' =>  '陕西省' (length=9)2 => array (size=8)'id' =>  '3' (length=1)'name' =>  '周改娟' (length=9)'sex' =>  '女' (length=3)'age' =>  '28' (length=2)'edu' =>  '大专' (length=6)'salary' =>  '8000.00' (length=7)...

2、sql中带变量进行查询

$id = 5;
$pdo = new \PDO('mysql:host=127.0.0.1;dbname=test','root','123456');
//查询操作
$stmt = $pdo->query("select * from user where id ='{$id}' limit 1");
$data = $stmt->fetch(2);
var_dump($data);

3、如果是根据用户传过来的值进行查询,为了防止sql注入,就需要预处理之后再进行查询

$dsn = "mysql:dbname=test;host=127.0.0.1";
$pdo = new PDO($dsn,'root','root');
$name = '孙娟';//这里的$name是接收用户传过来的值,这里我们为了简洁,直接定位
$sql = "select * from student where name=:name";
$stmt = $pdo->prepare($sql);
$stmt->execute(array('name'=>$name));
var_dump($stmt->fetch(2));

结果同样可以正常信息显示:

array (size=8)'id' =>  '6' (length=1)'name' =>  '孙娟' (length=6)'sex' =>  '女' (length=3)'age' =>  '24' (length=2)'edu' =>  '大本' (length=6)'salary' =>  '12300.00' (length=8)'bonus' =>  '1080.00' (length=7)'city' =>  '北京市' (length=9) (size=8)'id' =>  '6' (length=1)'name' =>  '孙娟' (length=6)'sex' =>  '女' (length=3)'age' =>  '24' (length=2)'edu' =>  '大本' (length=6)'salary' =>  '12300.00' (length=8)'bonus' =>  '1080.00' (length=7)'city' =>  '北京市' (length=9)