Php 未定义的属性：illumb\Database\elount\Relations\BelongsTo:：$diffi\u lvl\u name

在创建关系时，Laravel 5.7中出现错误，我创建的关系为：Question.php:

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

public function questions() {
    return $this->hasMany('App\Question');
}

public function index()
{
    $questions = Question::all();
    return view('questions.index', compact('questions'));
}

public function up()
{
    Schema::create('difficulty_levels', function (Blueprint $table) {
        $table->engine = 'InnoDB';
        $table->increments('id');
        $table->string('diffi_lvl_name');
        $table->timestamps();
    });
}

public function up()
{
    Schema::create('questions', function (Blueprint $table) {
        $table->engine = 'InnoDB';
        $table->increments('id');
        $table->text('question');
        $table->unsignedInteger('difficulty_level_id');
        $table->foreign('difficulty_level_id')->references('id')->on('difficulty_levels');
        $table->timestamps();
    });
}

和DifficultyLevel.php:

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

public function questions() {
    return $this->hasMany('App\Question');
}

public function index()
{
    $questions = Question::all();
    return view('questions.index', compact('questions'));
}

public function up()
{
    Schema::create('difficulty_levels', function (Blueprint $table) {
        $table->engine = 'InnoDB';
        $table->increments('id');
        $table->string('diffi_lvl_name');
        $table->timestamps();
    });
}

public function up()
{
    Schema::create('questions', function (Blueprint $table) {
        $table->engine = 'InnoDB';
        $table->increments('id');
        $table->text('question');
        $table->unsignedInteger('difficulty_level_id');
        $table->foreign('difficulty_level_id')->references('id')->on('difficulty_levels');
        $table->timestamps();
    });
}

之后，我使用：

@foreach ($questions as $question)
    {{ dd($question->diffi_lvl()->diffi_lvl_name) }}
@endforeach

和QuestionController.php:

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

public function questions() {
    return $this->hasMany('App\Question');
}

public function index()
{
    $questions = Question::all();
    return view('questions.index', compact('questions'));
}

public function up()
{
    Schema::create('difficulty_levels', function (Blueprint $table) {
        $table->engine = 'InnoDB';
        $table->increments('id');
        $table->string('diffi_lvl_name');
        $table->timestamps();
    });
}

public function up()
{
    Schema::create('questions', function (Blueprint $table) {
        $table->engine = 'InnoDB';
        $table->increments('id');
        $table->text('question');
        $table->unsignedInteger('difficulty_level_id');
        $table->foreign('difficulty_level_id')->references('id')->on('difficulty_levels');
        $table->timestamps();
    });
}

难度级迁移：

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

public function questions() {
    return $this->hasMany('App\Question');
}

public function index()
{
    $questions = Question::all();
    return view('questions.index', compact('questions'));
}

public function up()
{
    Schema::create('difficulty_levels', function (Blueprint $table) {
        $table->engine = 'InnoDB';
        $table->increments('id');
        $table->string('diffi_lvl_name');
        $table->timestamps();
    });
}

public function up()
{
    Schema::create('questions', function (Blueprint $table) {
        $table->engine = 'InnoDB';
        $table->increments('id');
        $table->text('question');
        $table->unsignedInteger('difficulty_level_id');
        $table->foreign('difficulty_level_id')->references('id')->on('difficulty_levels');
        $table->timestamps();
    });
}

和迁移问题：

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

public function questions() {
    return $this->hasMany('App\Question');
}

public function index()
{
    $questions = Question::all();
    return view('questions.index', compact('questions'));
}

public function up()
{
    Schema::create('difficulty_levels', function (Blueprint $table) {
        $table->engine = 'InnoDB';
        $table->increments('id');
        $table->string('diffi_lvl_name');
        $table->timestamps();
    });
}

public function up()
{
    Schema::create('questions', function (Blueprint $table) {
        $table->engine = 'InnoDB';
        $table->increments('id');
        $table->text('question');
        $table->unsignedInteger('difficulty_level_id');
        $table->foreign('difficulty_level_id')->references('id')->on('difficulty_levels');
        $table->timestamps();
    });
}

但它给了我这个错误作为

未定义的属性：illumb\Database\elounce\Relations\BelongsTo:$diffi\u lvl\u name

注意：我也使用了这个

{dd（$question->diffi\u lvl->diffi\u lvl\u name）}

获取试图获取非对象的属性

---

您已使用修复了第一个错误

$question->diffi_lvl->diffi_lvl_name

对于第二个错误，有一些可能性

• 您的问题模型没有任何困难级别
• 我们必须查看您的表结构。可能您错误地映射了外键。您的外键是否在“问题”表中命名为“难度\级别\ id”

---

按以下方式更改您的关系：

public function diffi_lvl() {
    return $this->belongsTo('App\DifficultyLevel', 'difficulty_level_id');
}

public function questions() {
    return $this->hasMany('App\Question', 'difficulty_level_id');
}

然后，以下各项应起作用：

@foreach ($questions as $question)
    {{ dd($question->diffi_lvl->diffi_lvl_name) }}
@endforeach

有关更多信息，请阅读上的文档

编辑：实际上，似乎只要做以下几点就可以了：

public function diffi_lvl() {
    return $this->belongsTo('App\DifficultyLevel', 'difficulty_level_id');
}

public function questions() {
    return $this->hasMany('App\Question');
}

---

你能给我们看看你的模型吗？是的，我现在编辑了chk谢谢。我回答了。我认为你在做错误的关系，因为问题属于1个不同级别，难度级别有很多问题，不是吗？顺便说一句，感谢你的回答，它现在工作得很有魅力，你能告诉我在关系中添加

难度级别id

的作用是什么吗？？？既然你将方法名称定义为

diffi\u lvl

，Laravel将尝试在您的表中查找不存在的

diffi\u lvl\u id

。因此，您必须显式定义另一个外键。文档中提到了这一点。好运：）不需要更改关系，只需添加外键，因为问题属于1个困难级别，难度级别有很多问题，不是吗？关系很好。您只需要指定外键yes。