[英]OOP PHP integrate mysqli_query
我将编辑问题以使其更清楚,这样您就可以看到我现在所拥有的内容,并且可以更轻松地理解问题。
<?php
$mysqli = new mysqli("localhost", "user", "password", "test");
class building
{
private $mysqli;
public $buildingid;
public $userid;
public $buildinglevel;
public function __construct($buildingid, $userid, \mysqli $mysqli)
{
$this->buildinglevel;
$this->mysqli = $mysqli;
}
public function getLevel()
{
return $this->mysqli->query("SELECT ".$this->buildingid." FROM worlds WHERE city_userid=".$this->userid."");
}
}
}
?>
然后,我用它来创建和使用函数:
$cityHall = new building("cityHall",$user['id'],$mysqli);
echo $cityHall->getLevel();
结果空白,什么也没有发生。
您应该将mysqli实例注入到建筑类的__construct()中:
$ mysqli =新的mysqli('user','password','localhost','test');
如果($ mysqli-> connect_errno){printf(“连接失败:%s \\ n”,$ mysqli-> connect_error); }
class building
{
private $mysql;
private $buildingid;
private $userid;
// I need to have a mysqli_query here to get the info for the correct building,
//to be able to set the "buildinglevel" for each object from the MYSQL DB, seems basic
//but none of the things ive tried has worked.
public function __construct($buildingid, $userid, $mysqli)
{
$this->buildinglevel;
$this->mysqli = $mysqli;
$this->userid = (int)$userid;
$this->buildingid= (int)$buildingid;
}
public function getLevel()
{
$query = $this->mysqli->query("SELECT ".$this->buildingid." FROM worlds WHERE city_userid=".$this->userid);
$row = $query->fetch_assoc();
if (!$query) {
return $this->mysqli->error;
}
if ($query->num_rows == 0) {
return 'no database records found';
}
return $row;
}
}
$Bulding = new building("cityHall", $user['id'], $mysqli);
$level = $Bulding->getLevel();
var_dump($level);
对象是封装行为的单元,这些行为通过方法暴露给其他对象。 从数据库检索到的公共属性的包装器不是面向对象的编程工具。 实际上, mysqli
可以通过fetch_object
为您完成此fetch_object
:
$result = $mysqli->query($query);
while ($building = $result->fetch_object()) {
// access properties via $building->buildingid, etc.
}
除非building
类实际上通过方法提供功能并实现某种抽象,否则不需要它。 相反,您可以使用包装数据库( mysqli
)的DAO(数据访问对象),并且其检索的数据由模型使用。
interface Dao {
public function get($id);
}
class BuildingDao implements Dao {
// DB can be a wrapper for mysqli
// but servers as an interface so it
// can be replaced easily
public function __construct(DB $db) {
$this->db = $db;
}
public function get($id) {
return $this->db->prepare(
"SELECT buildinglevel FROM building WHERE buildingid = ?"
)->execute($id)->fetch();
}
}
您的类似乎就是所谓的模型:它代表某种形式的数据,在您的情况下是特定的建筑物。
一种方法是将MySQLi对象作为构造函数对象以及要查询的建筑物的ID传递,并将结果分配给类属性。 如下所示:
<?php
class Building
{
private $db;
protected $id;
protected $level;
public function __construct(mysqli $db, $id = null)
{
$this->db = $db;
if (!is_null($id) && intval($id) > 0) {
$stmt = $this->db->prepare("SELECT buildingid, buildinglevel FROM building WHERE `id` = ?");
$stmt->bind_param('i', $id);
$stmt->execute();
$stmt->bind_result($this->id, $this->level);
$stmt->fetch();
}
}
public function getId()
{
return (int)$this->id;
}
public function getLevel()
{
return (int)$this->level;
}
}
然后,您可以按以下方式获取建筑物的属性:
$building = new Building($mysqli, 1);
printf('Building ID is %d and building level is %d', $building->getId(), $building->getLevel());
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