* PDO connection data
* 1. PDO is the middle layer, or abstraction layer, between PHP and other databases
* 2. PDO shields the differences between databases. Provides a unified access interface to PHP
* 3. The first step in using PDO is to generate a PDO object. All functions must be called using this object
* 4. Success Return PDO object, failure throws exception
//1. Configuration parameters
* DNS: Data source
* Basic format: Database type: attribute 1: value 1; Attribute 2: Value 2;...
* Type: such as mysqli, oracle, etc.
* Attribute: host, default database, default character set, default port number
* For example: mysql:host=127.0.0.1;dbname=php;charset=utf8;port=3306;
$dsn = 'mysql:host=localhost; dbname=php; charset=utf8; port=3306';
//Database user name
$userName = 'root';
//Database user password
$password = 'root';
//Configure connection properties
$options = [ PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION, //设置错误模式 PDO::ATTR_CASE => PDO::CASE_NATURAL, //数据表字段保持不变 PDO::ATTR_EMULATE_PREPARES => true, //启用PDO模拟 PDO::ATTR_PERSISTENT => true, //启用持久性连接 ];
//Use try-catch() to catch possible errors
try { //调用PDO构造函数实例化PDO类,创建PDO对象 $pdo = new PDO($dsn, $userName, $password, $options); //连接是所有操作的基础,无论你设置的错误模式级别是什么,都会强制使用EXCEPTION异常模式 } catch (PDOException $e) { print 'Connect ERROR!:'.$e->getMessage(); //推荐使用英文提示,以防止页面中文乱码 die(); //连接错误是致命错误,必须停止脚本的执行 }
//Disconnect PDO connection
$pdo = null;
//Destroy the PDO object
unset($pdo);
//More often, you can use the abbreviation:
$pdo = new PDO('mysql:dbname=php;','root', 'root'); //其它参数取默认值