如何在许多关系中访问所有表数据

Question

I have 3 tables.

1.posts

2.categories

3.category_post.

My Posts Tables here :

+------------+------------------+------+-----+---------------------+----------------+
| Field      | Type             | Null | Key | Default             | Extra          |
+------------+------------------+------+-----+---------------------+----------------+
| id         | int(10) unsigned | NO   | PRI | NULL                | auto_increment |
| title      | varchar(255)     | NO   |     | NULL                |                |
| slug       | varchar(255)     | NO   |     | NULL                |                |
| reporter   | varchar(255)     | NO   |     | NULL                |                |
| meta       | varchar(255)     | NO   |     | 0                   |                |
| body       | text             | NO   |     | NULL                |                |
| image      | varchar(255)     | NO   |     | 0                   |                |
| top        | tinyint(1)       | NO   |     | 0                   |                |
| post_count | int(11)          | NO   |     | 0                   |                |
| created_at | timestamp        | NO   |     | 0000-00-00 00:00:00 |                |
| updated_at | timestamp        | NO   |     | 0000-00-00 00:00:00 |                |
+------------+------------------+------+-----+---------------------+----------------+

My Categories Table Here:

+---------------+------------------+------+-----+---------------------+----------------+
| Field         | Type             | Null | Key | Default             | Extra          |
+---------------+------------------+------+-----+---------------------+----------------+
| id            | int(10) unsigned | NO   | PRI | NULL                | auto_increment |
| name          | varchar(255)     | NO   |     | NULL                |                |
| category_slug | varchar(255)     | NO   |     | NULL                |                |
| parrent_id    | int(11)          | NO   |     | 0                   |                |
| created_at    | timestamp        | NO   |     | 0000-00-00 00:00:00 |                |
| updated_at    | timestamp        | NO   |     | 0000-00-00 00:00:00 |                |
+---------------+------------------+------+-----+---------------------+----------------+

My category_post table:

+-------------+------------------+------+-----+---------+----------------+
| Field       | Type             | Null | Key | Default | Extra          |
+-------------+------------------+------+-----+---------+----------------+
| id          | int(10) unsigned | NO   | PRI | NULL    | auto_increment |
| category_id | int(10) unsigned | NO   | MUL | NULL    |                |
| post_id     | int(10) unsigned | NO   | MUL | NULL    |                |
+-------------+------------------+------+-----+---------+----------------+

I can create post with multiple category selected . But When i want to showing post by category, then i can't access category table . That means, i want to view category name with each post .

Here is my Models:

In Category Model:

public function posts()
{
    return $this->belongsToMany('Post');
}

In Post Model:

public function categories()
{
    return $this->belongsToMany('Category');
}

My Query Helper function is for Post by category:

public static function cat_post($category, $limit, $top)
{
    $posts = Post::whereHas('categories', function($q) use ($category, $top)
        {
            $q->where('name', 'like', $category);
            $q->where('top', 'like', $top);

        })->with('categories')->take($limit)->orderBy('created_at', 'DESC')->get();
    return $posts;
}

I can view all post data . But category name not .

My Post Loops:

<?php $headline = Helper::head_post(10, 1); ?>

  @foreach ($headline as $post)
    <li><a href="">{{ $post->title }}</a></li>
  @endforeach

when i try this for category name not working:

  @foreach ($headline as $post)
    <li><a href="">{{ $post->categories->name }}</a></li>
  @endforeach

Please help me.

Answer 1

Because it's a many to many relation $post->categories->name will not work. It doesn't know which category (of the many) you want the name of.

So you could for example use $post->categories()->first()->name to get the name of the first category or loop over them to get the name of all categories.