Laravel - Eloquent Relationship (One to Many 일대다)

DB 테이블의 1대다 연결 설정

 

Post has many Comment

Commnet belongs to Post

• hasMany() 
• belongsTo()

Schema::create('posts', function (Blueprint $table) {
    $table->id();
    $table->string("name");
    $table->timestamps();
});

 

Schema::create('comments', function (Blueprint $table) {
    $table->id();
    $table->integer('post_id')->unsigned();
    $table->string("comment");
    $table->timestamps();
    $table->foreign('post_id')->references('id')->on('posts')
        ->onDelete('cascade');
});

 

hasMany()

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class Post extends Model
{
    public function comments()
    {
        return $this->hasMany(App\Models\Comment::class);
    }
}

 

belongsTo()

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class Comment extends Model
{
    public function post()
    {
        return $this->belongsTo(App\Models\Post::class);
    }
}

 

조회하기

$post = Post::find(1);
$comments = $post->comments;
dd($comments);

$comment = Comment::find(1);
$post = $comment->post;
dd($post);

 

저장하기

$post = Post::find(1);
$comment = new Comment;
$comment->comment = "Hi ItSolutionStuff.com";
$post = $post->comments()->save($comment);

 

saveMany()

$post = Post::find(1);

$comment1 = new Comment;
$comment1->comment = "Hi ItSolutionStuff.com Comment 1";
 
$comment2 = new Comment;
$comment2->comment = "Hi ItSolutionStuff.com Comment 2";
 
$post = $post->comments()->saveMany([$comment1, $comment2]);

 

연결시키기 associate()

$comment = Comment::find(1);
$post = Post::find(2);
$comment->post()->associate($post)->save();