OOP MySQLi Connect [英] OOP MySQLi Connect
本文介绍了OOP MySQLi Connect的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我是OOP的新手.我上课数据库
Im newbie in OOP. I have class Database
class Database{
private $host;
private $user;
private $pass;
private $db;
public $mysqli;
function db_connect(){
$this->host = 'localhost';
$this->user = 'root';
$this->pass = '';
$this->db = 'db';
$this->mysqli = new mysqli($this->host, $this->user, $this->pass, $this->db);
return $this->mysqli;
}
内部类数据库我具有函数db_num
Inside class Database i have function db_num
function db_num($sql){
$num = mysqli_num_rows(mysqli_query($this->mysqli,"{$sql}"));
return $num;
}
但是当我在con参数$ this-> mysqli中使用im时,它无法连接到数据库
But it cant connect to database when im using in con argument $this->mysqli
推荐答案
混合mysqli对象样式和过程样式是不好的做法.
It is bad practice to mix mysqli object style and procedural style.
尝试一下:
function db_num($sql){
$result = $this->mysqli->query($sql);
return $result->num_rows;
}
在调用db_num()
之前,请确保已连接到数据库,例如:
Be sure to connect to the database before you call db_num()
, e.g.:
$db = new Database();
$db->db_connect();
$db->db_num("SELECT fields FROM YourTable");
在我看来,更干净的方法是在构造函数中调用db_connect
:
A cleaner way in my opinion would be to call db_connect
inside the constructor:
class Database{
private $host;
private $user;
private $pass;
private $db;
public $mysqli;
public function __construct() {
$this->db_connect();
}
private function db_connect(){
$this->host = 'localhost';
$this->user = 'root';
$this->pass = '';
$this->db = 'db';
$this->mysqli = new mysqli($this->host, $this->user, $this->pass, $this->db);
return $this->mysqli;
}
public function db_num($sql){
$result = $this->mysqli->query($sql);
return $result->num_rows;
}
}
$db = new Database();
$db->db_num("SELECT fields FROM YourTable");
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