Laravelでマイグレーションする

はじめに

• Laravelで下記のテーブルを用意する

マイグレーションファイルの作成

php artisan make:migration create_categories_table
php artisan make:migration create_articles_table
php artisan make:migration create_article_categories_table

マイグレーションファイルの構成

• categoriesテーブルのファイル

<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

class CreateCategoriesTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('categories', function (Blueprint $table) {
            $table->id();
            $table->string('name');
            $table->timestamps();
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('categories');
    }
}

• articlesテーブルのファイル

<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

class CreateArticlesTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('articles', function (Blueprint $table) {
            $table->id();
            $table->unsignedBigInteger('user_id');
            $table->foreign('user_id')->references('id')->on('users')->onDelete('cascade');
            $table->string('title');
            $table->text('body');
            $table->string('tag')->nullable();           
            $table->timestamps();
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('articles');
    }
}

• article_categoriesテーブルのファイル

<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

class CreateArticleCategoriesTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('article_categories', function (Blueprint $table) {
            $table->id();
            $table->unsignedBigInteger('category_id');
            $table->foreign('category_id')->references('id')->on('categories')->onDelete('cascade');
            $table->unsignedBigInteger('article_id');
            $table->foreign('article_id')->references('id')->on('articles')->onDelete('cascade');            
            $table->timestamps();
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('article_categories');
    }
}

マイグレーション実行

• migrateコマンドでテーブルを作成する

$  php artisan migrate
Migrating: 2020_10_02_091649_create_categories_table
Migrated:  2020_10_02_091649_create_categories_table (147.28ms)
Migrating: 2020_10_02_091655_create_articles_table
Migrated:  2020_10_02_091655_create_articles_table (228.39ms)
Migrating: 2020_10_02_091659_create_article_categories_table
Migrated:  2020_10_02_091659_create_article_categories_table (404.55ms)

テーブルの作成の確認

• テーブルも外部制約が付与された状態で作成されている

| categories | CREATE TABLE `categories` (
  `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(255) COLLATE utf8mb4_unicode_ci NOT NULL,
  `created_at` timestamp NULL DEFAULT NULL,
  `updated_at` timestamp NULL DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci |


| articles | CREATE TABLE `articles` (
  `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
  `user_id` bigint(20) unsigned NOT NULL,
  `title` varchar(255) COLLATE utf8mb4_unicode_ci NOT NULL,
  `body` text COLLATE utf8mb4_unicode_ci NOT NULL,
  `tag` varchar(255) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `created_at` timestamp NULL DEFAULT NULL,
  `updated_at` timestamp NULL DEFAULT NULL,
  PRIMARY KEY (`id`),
  KEY `articles_user_id_foreign` (`user_id`),
  CONSTRAINT `articles_user_id_foreign` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`) ON DELETE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci |


| article_categories | CREATE TABLE `article_categories` (
  `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
  `category_id` bigint(20) unsigned NOT NULL,
  `article_id` bigint(20) unsigned NOT NULL,
  `created_at` timestamp NULL DEFAULT NULL,
  `updated_at` timestamp NULL DEFAULT NULL,
  PRIMARY KEY (`id`),
  KEY `article_categories_category_id_foreign` (`category_id`),
  KEY `article_categories_article_id_foreign` (`article_id`),
  CONSTRAINT `article_categories_article_id_foreign` FOREIGN KEY (`article_id`) REFERENCES `articles` (`id`) ON DELETE CASCADE,
  CONSTRAINT `article_categories_category_id_foreign` FOREIGN KEY (`category_id`) REFERENCES `categories` (`id`) ON DELETE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci |

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