App\Tasks::first()->项目； in artisan tinker returns null，无论如何:(

Question

tinker 中的以下代码 return 是一个空值，而它应该 return 第一个任务链接到的项目。

App\Task::first()->projects;

已经尝试重命名迁移中的方法名称、列名称，尝试退出修补程序并重新登录

项目迁移

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

任务迁移

public function up()
    {
        Schema::create('tasks', function (Blueprint $table) {
            $table->bigIncrements('id');
            $table->unsignedInteger('project_id');
            $table->string('description');
            $table->boolean('completed')->default(false);
            $table->timestamps();
        });
    }

Project.php

use App\Task;

class Project extends Model
{
    protected $fillable = ['title','description'];

    public function tasks(){
      return $this->hasMany(Task::class);
    }
}

Task.php

use App\Project;

class Task extends Model
{
  protected $fillable = [
    'completed'
  ];
  public function projects(){
    return $this->belongsTo(Project::class);
  }
}

如果有人可以查看这段代码并让我知道我在哪里犯了任何 conventional\idiotic 错误（因为我是路由模型绑定的新手），那将会很有帮助！

Answer 1

一个任务属于一个项目，所以将projects重命名为project，因为它是单数的。如果您保留项目，则提供列名称作为第二个参数：

public function projects(){
   return $this->belongsTo(Project::class, 'project_id');
}

// I suggest this
public function project(){
   return $this->belongsTo(Project::class);
}

你的column类型不一样，project的id用的是Big Integer，reference用的是Integer，所以：

$table->unsignedInteger('project_id');

应该是这样的：

$table->unsignedBigInteger('project_id');

// also good to make the relationship on the Database level:

$table->foreign('project_id')->references('id')->on('projects')->onDelete('cascade');

App\Tasks::first()->项目； in artisan tinker returns null，无论如何:(

App\Tasks::first()->projects; in artisan tinker returns null, no matter what :(

php

laravel

eloquent

eloquent-relationship