pdo connection method in php

* 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