php - Laravel 多层 Eloquent 关系

Question

我有以下 Eloquent 。

体积，问题，类别，文章，文章翻译，

音量可能有很多问题。问题可以有很多类别。类别可以有很多文章。文章可以有多个翻译。

那么如何从 Article/ArticleTranslation 中获取 Volume？

Answer 1

首先是您的模型。

..
class Volume extends Model {
  public function issues() {
    return $this->hasMany(Issue::class);
  }
}

class Issue extends Model {
  public function volume() {
    return $this->belongsTo(Volume::class);
  }
  public function categories() {
    return $this->hasMany(Category::class);
  }
}

class Category extends Model {
  public function issue() {
    return $this->belongsTo(Issue::class);
  }
  public function articles() {
    return $this->hasMany(Article::class);
  }
  public function articlesTranslated() {
    return $this->hasMany(ArticleTranslated::class);
  }
}

class Article extends Model {
  public function category() {
    return $this->belongsTo(Category::class);
  }
}
..

然后在你的代码中:

..
$articles = Articles::all();
$volumes = [];
foreach ($articles as $article) {
  $volumes[] = $article->category->issue->volume;
}
..

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