Laravel 10 One to Many Eloquent Relationship Tutorial

In Laravel, Eloquent provides a powerful and expressive way to define and work with database relationships. You can use various types of relationships to establish connections between your models.

Step 1 :Create Migrations:

posts table migration: 

<?php
  
    use Illuminate\Database\Migrations\Migration;
    use Illuminate\Database\Schema\Blueprint;
    use Illuminate\Support\Facades\Schema;
      
    return new class extends Migration
    {
        /**
         * Run the migrations.
         *
         * @return void
         */
        public function up(): void
        {
            Schema::create('posts', function (Blueprint $table) {
                $table->id();
                $table->string("name");
                $table->timestamps();
            });
        }
      
        /**
         * Reverse the migrations.
         *
         * @return void
         */
        public function down(): void
        {
            Schema::dropIfExists('posts');
        }
    };

comments table migration:

<?php
  
    use Illuminate\Database\Migrations\Migration;
    use Illuminate\Database\Schema\Blueprint;
    use Illuminate\Support\Facades\Schema;
      
    return new class extends Migration
    {
        /**
         * Run the migrations.
         *
         * @return void
         */
        public function up(): void
        {
            Schema::create('comments', function (Blueprint $table) {
                $table->id();
                $table->foreignId('post_id')->constrained('posts');
                $table->string("comment");
                $table->timestamps();
            });
        }
      
        /**
         * Reverse the migrations.
         *
         * @return void
         */
        public function down(): void
        {
            Schema::dropIfExists('comments');
        }
    };

Step 2:Create Models:

app/Models/Post.php 

<?php
  
    namespace App\Models;
      
    use Illuminate\Database\Eloquent\Factories\HasFactory;
    use Illuminate\Database\Eloquent\Model;
    use Illuminate\Database\Eloquent\Relations\HasMany;
      
    class Post extends Model
    {
        use HasFactory;
     
        /**
         * Get the comments for the blog post.
         *   
         * Syntax: return $this->hasMany(Comment::class, 'foreign_key', 'local_key');
         *
         * Example: return $this->hasMany(Comment::class, 'post_id', 'id');
         * 
         */
        public function comments(): HasMany
        {
            return $this->hasMany(Comment::class);
        }
    }

app/Models/Comment.php

<?php
  
    namespace App\Models;
      
    use Illuminate\Database\Eloquent\Factories\HasFactory;
    use Illuminate\Database\Eloquent\Model;
    use Illuminate\Database\Eloquent\Relations\BelongsTo;
      
    class Comment extends Model
    {
        use HasFactory;
      
        /**
         * Get the post that owns the comment.
         *  
         * Syntax: return $this->belongsTo(Post::class, 'foreign_key', 'owner_key');
         *
         * Example: return $this->belongsTo(Post::class, 'post_id', 'id');
         * 
         */
        public function post(): BelongsTo
        {
            return $this->belongsTo(Post::class);
        }
    }
    

Step 3: Retrieve Records

<?php
  
    namespace App\Http\Controllers;
      
    use Illuminate\Http\Request;
    use App\Models\Post;
      
    class PostController extends Controller
    {
        /**
         * Write code on Method
         *
         * @return response()
         */
        public function index(Request $request)
        {
            $comments = Post::find(1)->comments;
      
            dd($comments);
        }
    }

<?php
 
    namespace App\Http\Controllers;
      
    use Illuminate\Http\Request;
    use App\Models\Comment;
      
    class PostController extends Controller
    {
        /**
         * Write code on Method
         *
         * @return response()
         */
        public function index(Request $request)
        {
            $post = Comment::find(1)->post;
      
            dd($post);
        }
    }

Step 4: Create Records

<?php
  
    namespace App\Http\Controllers;
      
    use Illuminate\Http\Request;
    use App\Models\Post;
    use App\Models\Comment;
      
    class PostController extends Controller
    {
        /**
         * Write code on Method
         *
         * @return response()
         */
        public function index(Request $request)
        {
            $post = Post::find(1);
       
            $comment = new Comment;
            $comment->comment = "Hi webthestuff.com";
               
            $post = $post->comments()->save($comment);
        }
    }

<?php
  
    namespace App\Http\Controllers;
       
    use Illuminate\Http\Request;
    use App\Models\Post;
    use App\Models\Comment;
      
    class PostController extends Controller
    {
        /**
         * Write code on Method
         *
         * @return response()
         */
        public function index(Request $request)
        {
            $post = Post::find(1);
       
            $comment1 = new Comment;
            $comment1->comment = "Hi webthestuff.com Comment 1";
               
            $comment2 = new Comment;
            $comment2->comment = "Hi webthestuff.com Comment 2";
               
            $post = $post->comments()->saveMany([$comment1, $comment2]);
        }
    }

<?php
   
    namespace App\Http\Controllers;
      
    use Illuminate\Http\Request;
    use App\Models\Post;
    use App\Models\Comment;
      
    class PostController extends Controller
    {
        /**
         * Write code on Method
         *
         * @return response()
         */
        public function index(Request $request)
        {
            $comment = Comment::find(1);
            $post = Post::find(2);
               
            $comment->post()->associate($post)->save();
        }
    }