php - 我需要通过使用引用帖子中的表用户的外键来了解帖子的所有者

Question

违反完整性约束:1452 无法添加或更新子行:外键约束失败(projects.posts、CONSTRAINT posts_user_id_foreign FOREIGN关键(user_id)引用用户(id))

class CreatePostsTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
    */
    public function up()
    {
        Schema::create('posts', function (Blueprint $table) {
            $table->engine ='InnoDB';
            $table->increments('id');
            $table->string('jobtitle');
            $table->string('location');
            $table->string('jobtype');
            $table->string('jobdesc');
            $table->string('companyname');
            $table->string('howto');
            $table->integer('user_id')->unsigned();
            $table->timestamps();
        });

        Schema::table('posts', function($table) {                                                                                              
            $table->foreign('user_id')->references('id')->on('users');
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
    */
    public function down()
    {
         Schema::dropIfExists('posts');
    }
}

发布模型

class Posts extends Model
{
    //
    protected $fillable =[
        'jobtitle', 
        'location',
        'jobtype',
        'jobdesc',
        'companyname',
        'howto',
        'user_id' 
    ];             

    protected $guarded = array();

    public static $rules = array();

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

用户模型

public function posts()
{
    return $this->hasMany('App\Posts','user_id ');
}

Answer 1

你不需要在 MySQL 端声明外键，你至少必须创建一个 user_id 列(你确实有)，Laravel 将使用它作为外键。

要获取创建帖子的用户，只需引用关系即可。

$owner = \App\Post::user->name; // get the user who created the post.