php 全局变量 - 数据库连接？
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Global Variable - database connection?
提问by Peter
I am trying to connect to a database (MySQLi) just once, but am having problems doing so.
我只是尝试连接到数据库 (MySQLi) 一次，但在这样做时遇到了问题。
How do I make a connection global for the entire script? There are multiple files (index.php, /classes/config.class.php, /classes/admin.class.php, etc).
如何为整个脚本建立全局连接？有多个文件（index.php、/classes/config.class.php、/classes/admin.class.php 等）。
I've tried the following:
我尝试了以下方法：
In: config.class.php
在：config.class.php
public static $config = array();
public static $sql;
function __construct() {
// database
db::$config['host'] = 'localhost';
db::$config['user'] = '_';
db::$config['pass'] = '_';
db::$config['db'] = '_';
// connect
db::$sql = new mysqli(db::$config['host'], db::$config['user'], db::$config['pass'], db::$config['db']);
}
Again, in config.class.php
再次，在 config.class.php
public function contectToDatabase($sql){
$sql = new mysqli(db::$config['host'], db::$config['user'], db::$config['pass'], db::$config['db']);
$this->sql = $sql;
}
I use the class with the following code:
$config = new db();
我使用带有以下代码的类：
$config = new db();
I really am puzzled at how I'm to do this. Can anyone help?
我真的很困惑我该如何做到这一点。任何人都可以帮忙吗？
--- Edit --- This is my new config.class.php file:
--- 编辑 --- 这是我的新 config.class.php 文件：
public static $config = array();
public static $sql;
private static $db;
private $connection;
public function __construct() {
// database
db::$config['host'] = '_';
db::$config['user'] = '_';
db::$config['pass'] = '_';
db::$config['db'] = '_';
// connect
$this->connection = new mysqli(db::$config['host'], db::$config['user'], db::$config['pass'], db::$config['db']);
}
function __destruct() {
$this->connection->close();
}
public static function getConnection() {
if($db == null){
$db = new db();
}
return $db->connection;
}
And this is how I'm loading it:
这就是我加载它的方式：
require_once("classes/config.class.php");
$config = new db();
$sql = db::getConnection();
However, running a real_escape_string results in the following errors:
但是，运行 real_escape_string 会导致以下错误：
Warning: mysqli::real_escape_string() [mysqli.real-escape-string]: Couldn't fetch mysqli in /home/calico/_/_.com/_/index.php on line 20
Warning: mysqli::query() [mysqli.query]: Couldn't fetch mysqli in /home/calico/_/_.com/_/index.php on line 28
回答by daiscog
Personally, I use a singleton class. Something like this:
就个人而言，我使用单例类。像这样的东西：
<?php
class Database {
private static $db;
private $connection;
private function __construct() {
$this->connection = new MySQLi(/* credentials */);
}
function __destruct() {
$this->connection->close();
}
public static function getConnection() {
if (self::$db == null) {
self::$db = new Database();
}
return self::$db->connection;
}
}
?>
Then just use $db = Database::getConnection();wherever I need it.
然后就$db = Database::getConnection();在我需要的地方使用。
