雄辩的关系问题：belongsTo

Question

我是 Laravel 的新手。

我有这些模型：

• 模态，
• 报告组，
• 报告，
• 用户

基本上，我正在尝试建立一些关系：

- 一个 ReportsGroup 属于一个 Modality，

- 一个 Modality 有许多 ReportsGroup，

- 一个 ReportsGroup 有许多报告，

- 报告属于 ReportsGroup，

- 一份报告有一个用户，

- 一个用户有很多报告。

（粗体线是我无法达到的关系......）

型号：

Modality.php

    namespace App;

    use Illuminate\Database\Eloquent\Model;

    class Modality extends Model
    {
        public function reportGroups()
        {
          $this->hasMany(ReportsGroup::class);
        }
    }

ReportsGroup.php：

namespace App;

use Illuminate\Database\Eloquent\Model;

class ReportsGroup extends Model
{
  public function modality()
  {
    return $this->belongsTo(Modality::class);
  }
  public function reports()
  {
    return $this->hasMany(Report::class);
  }
}

报告.php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Report extends Model
{
    public function author()
    {
      return $this->belongsTo(User::class, 'author_id');
    }
    public function reportsGroup()
    {
      return $this->belongsTo(ReportsGroup::class, 'reportsGroup_id');
    }
}

迁移：

表格形式：

public function up()
    {
        Schema::create('modalities', function (Blueprint $table) {
            $table->id();
            $table->string('title')->nullable();
            $table->text('description')->nullable();
            $table->boolean('is_active')->default(true);
            $table->boolean('is_free')->default(true);
            $table->timestamps();
        });
    }

表格报告组：

public function up()
{
  Schema::create('reports_groups', function (Blueprint $table) {
      $table->id();
      $table->unsignedBigInteger('modality_id');
      $table->string('title');
      $table->text('description')->nullable();
      $table->timestamps();
  });
}

表格报告

  public function up()
    {
        Schema::create('reports', function (Blueprint $table) {
            $table->id();
            $table->unsignedBigInteger('reportsGroup_id');
            $table->string('title');
            $table->text('indication')->nullable();
            $table->text('technique')->nullable();
            $table->text('conclusion')->nullable();
            $table->text('recommandations')->nullable();
            $table->unsignedBigInteger('author_id');
            $table->boolean('is_visible')->defaut(true);
            $table->boolean('is_free')->default(true);
            $table->timestamps();

            $table->index('reportsGroup_id');
            $table->index('author_id');
        });
    }

表用户：

public function up()
{
    Schema::create('users', function (Blueprint $table) {
        $table->id();
        $table->string('name');
        $table->string('email')->unique();
        $table->timestamp('email_verified_at')->nullable();
        $table->string('password');
        $table->rememberToken();
        $table->timestamps();
    });
}

正如我所写，似乎唯一有效的关系是 ReportsGrouop 属于 Modality...

我被这个问题困扰了好几天......

请帮忙！ 谢谢，

尼古拉斯

Answer 1

添加参考 ID，如

$table->unsignedBigInteger('modality_id');

是不够的。 您还应该添加一个外键：

$table->foreign('modality_id')->references('id')->on('modalities');

https://laravel.com/docs/6.x/migrations#foreign-key-constraints