Question

我是laravel的新手，必须为3个表定义关系。表格是事件，类别，包。

事件可以有多个类别，每个类别可以有多个包。相同的类别可以在各种事件中。

到目前为止，我有以下表格，但不确定我是否采取了正确的方法：

Table:events
id - int
title - varchar ...

Table: categories
id - int
name - varchar

Table:packages
id - int
name - varchar
price - decimal

Table:category_package
category_id - int
package_id - int

Table:event_package
event_id - int
package_id - int

内包装模型我有：

public function categories()
{
    return $this->belongsToMany('\App\Category');
}

public function events()
{
    return $this->belongsToMany('\App\Event');
}

内部事件和类别模型我有：

public function packages()
{
    return $this->belongsToMany('\App\Package');
}

当我查询特定事件及其关系时，我想得到以下结果：

[
   "events" => [
        "id" => 1,
        "title" => "whatever title",
        "categories" => [
            [
            "id" => 1,
            "name" => "the category",
            "packages" => [
                ["id" => 1, "name" => "pack1"],
                ["id" => 2, "name" => "pack2"],
                ["id" => 3, "name" => "pack3"]
            ]],
            [
            "id" => 2,
            "name" => "second cat",
            "packages" => [
                ["id" => 4, "name" => "pack4"],
                ["id" => 5, "name" => "pack5"],
                ["id" => 6, "name" => "pack6"]
            ]],
        ]
    ]
]

这是否可能在laravel中，我将如何去做。我很确定我没有采取正确的方法。

由于

Answer 1

根据您的表格结构和评论，您似乎想要进行此设置：

Event有多个Packages
Package属于一个Event
Category有多个Packages
Package属于一个Category

您不需要数据透视表（category_package和event_package），因此请删除它们。然后，您的packages表格需要添加event_id和category_id字段。

Table:packages
id - int
name - varchar
price - decimal
event_id - int
category_id - int

您应该像这样设置模型：

class Event extends Model {
    public function packages() {
        return $this->hasMany('App\Package');
    }
}

class Category extends Model {
    public function packages() {
        return $this->hasMany('App\Package');
    }
}

class Package extends Model {
    public function event() {
        return $this->belongsTo('App\Event');
    }

    public function category() {
        return $this->belongsTo('App\Category');
    }
}

你想要在你的问题中得到的数组不能被优雅地检索，你必须做一些手工工作，但如果你使用eager loading with constraints就不难

要获得一个Event及其Categories和Packages，您可以这样做：

$event = Event::find($eventId); // Or however you want to get the Event
$event['categories'] = Category::with(['packages' => function($query) use($event) {
    $query->where('event_id', $event->id);
}])->get();

要获得多个Events及其Categories和Packages，您只需使用循环并为每个Event添加类别。

$events = Event::all(); // Or however you want to get the Events
foreach ($events as $key => $event) {
    $events[$key]['categories'] = Category::with(['packages' => function($query) use ($event) {
        $query->where('event_id', $event->id);
    }])->get();
}

Laravel - 定义多表关系

1 个答案: