类之间共享PDO交互 [英] PDO interaction shared among classes

问题描述

我为我拥有的每个数据库表都有一个类，例如events表的行存储在Event类中.对于我编写的每个类，都有几种完全相同的方法，只是使用了不同的变量或列名.例如:

I have a class for each database table I have, for example events table's rows are stored in Event classes. For each class I write, there are several methods that are exactly the same just with different variables or column names. For example:

玩家类update()

public function update() {
    $conn = new PDO( db_host, db_user, db_pw );
    $sql = "UPDATE players SET name=:name, picture=:picture, position=:position, num=:num, team=:team, description=:description WHERE id = :id";
    $st = $conn->prepare ( $sql );
    $st->bindValue( ":name", $this->name, PDO::PARAM_STR );
    $st->bindValue( ":picture", $this->picture, PDO::PARAM_STR );
    $st->bindValue( ":position", $this->position, PDO::PARAM_STR );
    $st->bindValue( ":num", $this->num, PDO::PARAM_INT );
    $st->bindValue( ":team", $this->team, PDO::PARAM_INT );
    $st->bindValue( ":description", $this->description, PDO::PARAM_STR);
    $st->bindValue( ":id", $this->id, PDO::PARAM_INT );
    $st->execute();
    $conn = null;
}

团队课程update()

public function update() {
    $conn = new PDO( db_host, db_user, db_pw );
    $sql = "UPDATE teams SET name=:name, sname=:sname, logo=:logo, sport=:sport WHERE id = :id";
    $st = $conn->prepare ( $sql );
    $st->bindValue( ":name", $this->name, PDO::PARAM_STR );
    $st->bindValue( ":sname", $this->sname, PDO::PARAM_STR );
    $st->bindValue( ":logo", $this->logo, PDO::PARAM_STR );
    $st->bindValue( ":sport", $this->sport, PDO::PARAM_STR );
    $st->bindValue( ":id", $this->id, PDO::PARAM_INT );
    $st->execute();
    $conn = null;
 }

您可以看到方法的要点是相同的，只是绑定到该语句的变量不同(更多方法就是这种情况).有没有简便的方法可以使每个类具有相同的基本update()，insert()，delete() ...方法，但具有各自的变量?我曾考虑过从超类继承基本行为，但从面向对象的角度来看，这没有多大意义(而且我不相信有任何方式可以说对于在该类中声明的每个公共变量")确保是否有一种使用合成的方法(或者说真的).

As you can see the point of the methods are the same it's just different variables being bound to the statement (this is the case with more methods). Is there an easy way to do it so that each class has the same basic update(), insert(), delete()... methods but with its respective variables? I have thought of inheriting basic behaviour from a super class but from OO point of view doesn't make much sense (and im not convinced there is any way of saying "for each public variable declared in this class") but I'm not sure if there is a way to do this using compositions (or at all, really).

推荐答案

是的，这是您正在谈论的婴儿ORM，并且很容易实现.

Yes, this a baby ORM you are talking about and it is quite easy to implement.

首先，使用所有常用方法(create()，update()，find()等)创建原型类.

First of all, create a prototype class, with all the common methods (create(), update(), find() etc).

abstract class BaseActiveRecord
{
    protected $_db;
    protected $_table;
    protected $_primary = 'id';
    protected $_fields = [];

    public function __construct($db)
    {
        $this->_db = $db;
    }
    public function read($id)
    {
        $sql = "SELECT * FROM `$this->_table` WHERE `$this->_primary` = ?";
        $stmt = $this->_db->prepare($sql);
        $stmt->execute([$id]);
        $stmt->setFetchMode(PDO::FETCH_INTO, $this);
        $stmt->fetch();
    }
    public function update()
    {
        $data = [];
        $set = "";
        foreach($this->_fields as $key)
        {
            $set .= "`$key` = :$key,";
            $data[$key]  = $this->{$key};
        }
        $set = rtrim($set, ",");
        $data[$this->_primary] = $this->{$this->_primary};
        $where = "$this->_primary = :$this->_primary";
        $sql = "UPDATE {$this->_table} SET $set WHERE $where";
        $this->_db->prepare($sql)->execute($data);
    }
}

如您所见，有一些新变量:

As you can see, there are some new variables:

• $_table保留特定类中使用的表名.
• $_primary保留将在find()和update()方法中使用的主键的名称，默认值为id.
• $_fields是一个非常重要的属性，它应包含此类的所有真实"属性的列表.它将用于create()和update()方法

• $_table holds the table name used in the particular class.
• $_primary holds the name of the primary key that will be used in the find() and update() methods, with the default value of id.
• $_fields is a very important property, it should contain the list of all "real" properties of this class. It will be used for create() and update() methods

然后只创建实际的类，扩展您的原型类，例如Team

Then just create actual classes, extending your prototype class, such as Team

class Team extends BaseActiveRecord
{
    protected $_table = "teams";
    protected $_fields = ['name', 'sname', 'logo', 'sport'];
}

如您所见，定义非常简单-在这里，您必须定义表和字段名称，以使我们的自动化工作.现在！您要做的就是简单地调用update()方法！

As you can see, the definition is fairly simple - here you have to define the table and field names in order to make our automation work. And now! All you have to do is to simply call update() method!

include 'pdo.php';
$team = new Team($pdo);
$team->read(1); // get the record from the database
$user->name = "Boston Celtics";
$user->sname = "Celtics";
$user->update(); // save the updated record.

请注意，您永远不要在每个方法内部创建新的数据库连接.创建一次，然后传递给您的类的构造函数.这是如何正确连接PDO .

Note that you should never create a new database connection inside of each method. Create it once and pass into constructor of your classes. Here is how to connect with PDO properly.

这篇关于类之间共享PDO交互的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！