数据库---PDO

以pikachu数据库为例，数据库名： pikachu

1.连接数据库

<?php

$dsn = 'mysql:host=localhost; port=3306; dbname=pikachu';   // 这里的空格比较敏感

$username = 'root';

$password = 'root';

try {

        $pdo = new PDO($dsn, $username, $password);

        var_dump($pdo);

}catch(PDOException $e){

        // echo $e->getMessage();

        die('Connection error:'. $e->getMessage());

}

?>

连接成功。 

2. pdo查询

<?php

$dsn = 'mysql:host=127.0.0.1; dbname=pikachu';

$username = 'root';

$pwd = 'root';

$pdo = new PDO($dsn, $username,$pwd); // 连接数据库

$sql = 'select * from users where id=:id';

$stmt = $pdo->prepare($sql);

$stmt->bindValue(':id',1);

$stmt->execute();

$rows = $stmt->fetchAll(PDO::FETCH_ASSOC);

echo '<pre>';

print_r($rows);

$pdo = null;

?>

:id   占位符 

 3.pdo更新

<?php

$dsn = 'mysql:host=127.0.0.1; dbname=pikachu';

$username = 'root';

$pwd = 'root';

$pdo = new PDO($dsn, $username,$pwd);

$sql = 'update users set level="4" where id=:id';

$stmt = $pdo->prepare($sql);

$stmt->bindValue(':id',1);

 stmt->execute();

$pdo = null;

?>

4.pdo插入

 <?php

$dsn = 'mysql:host=127.0.0.1; dbname=pikachu';

$username = 'root';

$pwd = 'root';

$pdo = new PDO($dsn, $username,$pwd);

$sql = 'insert into users(`id`,`username`,`password`,`level`)                                                            values(:id,:username,:password,:level)';

$stmt = $pdo->prepare($sql);

$stmt->bindValue(':id',4);

$stmt->bindValue(':username','Bob');

$stmt->bindValue(':password','e99a18c428cb38d5f260853678922e04');

$stmt->bindValue(':level','5');

     

$stmt->execute();

$id = $pdo->lastInsertId();

echo '<pre>';

var_dump($id);

$pdo = null;

?>

5. pdo删除

<?php

$dsn = 'mysql:host=127.0.0.1; dbname=pikachu';

$username = 'root';

$pwd = 'root';

$pdo = new PDO($dsn, $username,$pwd);

$sql = 'delete from pikachu where id = :id';

$stmt = $pdo->prepare($sql);

$stmt->bindValue(':id',1);

$stmt->execute();

// 返回受影响的行数，删除了多少行。

$rowCount = $stmt->rowCount();

echo '<pre>';

var_dump($rowCount);

$pdo = null;

?>