Php laravel Eloquent 模型的问题

发布于08月28日

我正在学习使用Laravel的MVC模式，而Eloquent 的模型对我来说是一种压倒性的感觉.Eloquent 模型返回表的列的集合，但我希望另一个表的集合成为该模型的属性.

我有三张桌子

Books个

id,
title

Contribution个

book_id,
contributor_id,
role

Author个

id,
name

我想要更改函数的返回值，如Model Books的all()、find()、get()等，以包括贡献者

从这一点开始:

[  "id" => "1", 
   "title" => "CS101" 
]

对此:

[ "id" => "1",
  "title" => "CS101",
  "contributors" => [
   [
    "id" => "1",
    "name" => "Einstein"
    "role" => "author"
   ],
   [
    "id" => "2",
    "name" => "Thomas"
    "role" => "translator"
   ]
  ]
]

我是不是应该使用Eloquent 并构建自己的模型，或者是否有可以覆盖的Eloquent 函数或更好的方法来实现这一点

推荐答案

首先，您需要创建Book::class和Author::class之间的关系

Book.php

namespace App\Models;
 
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\BelongsToMany;
 
class User extends Model
{
    /**
     * The Author that belong to the book.
     */
    public function contributors(): BelongsToMany
    {
        return $this->belongsToMany(Author::class, 'contribution', 'book_id', 'contributor_id')->withPivot('role');
    }
}

然后，您可以在运行查询时加载关系

$books = Book::with('contributors')->get();

$book = Book::with('contributors')->first();

这将导致 struct

[
  "id" => "1",
  "title" => "CS101",
  "contributors" => [
    [
      "id" => "1",
      "name" => "Einstein",
      "pivot" => [
        "role" => "Author",
      ]
    ],
    [
      "id" => "2",
      "name" => "Thomas"
      "pivot" => [
        "role" => "Translator",
      ]
    ]
  ]
]

最有趣的是，通过这种方式，关系将被Eager 加载，这意味着将只运行两个查询来获得结果.