Laravel 数据库迁移与 Seeder

小飞兽 Laravel 6 次阅读 2026-07-29

Laravel 的数据库迁移（Migration）和数据填充（Seeder）系统让你可以像管理代码一样管理数据库结构，确保团队成员之间的数据库 schema 保持一致。本文详细介绍其使用方法。

创建迁移

// 创建 articles 表迁移 php artisan make:migration create_articles_table // 在指定目录下创建 php artisan make:migration create_articles_table --path=database/migrations

// 创建已有表的迁移（用于修改表结构） php artisan make:migration add_views_to_articles_table --table=articles

迁移文件编写

// database/migrations/2024_01_01_000001_create_articles_table.php
use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;
return new class extends Migration
{
    public function up(): void
    {
        Schema::create("articles", function (Blueprint $table) {
            $table->id();                        // 主键自增
            $table->foreignId("user_id")        // 外键
                  ->constrained("users")
                  ->cascadeOnDelete();
            $table->foreignId("category_id")
                  ->nullable()
                  ->constrained("categories")
                  ->nullOnDelete();
            $table->string("title", 200);
            $table->string("slug", 200)->unique();
            $table->text("content")->nullable();
            $table->string("excerpt", 500)->nullable();
            $table->unsignedInteger("views")->default(0);
            $table->boolean("is_published")->default(false);
            $table->timestamp("published_at")->nullable();
            $table->timestamps();               // created_at + updated_at
            $table->softDeletes();              // deleted_at
// 索引
            $table->index(["category_id", "created_at"]);
            $table->index("slug");
        });
    }
public function down(): void
    {
        Schema::dropIfExists("articles");
    }
};

修改表结构

// 新增字段
Schema::table("articles", function (Blueprint $table) {
    $table->string("cover_image", 500)->after("title")->nullable();
    $table->boolean("is_featured")->default(false)->after("is_published");
});
// 修改字段（Laravel 10+）
Schema::table("articles", function (Blueprint $table) {
    $table->string("title", 250)->change();  // 改长度
    $table->renameColumn("excerpt", "summary");  // 重命名
});
// 删除字段
Schema::table("articles", function (Blueprint $table) {
    $table->dropColumn(["cover_image", "is_featured"]);
});
// 重命名表
Schema::rename("old_articles", "articles");

运行迁移

// 运行所有迁移 php artisan migrate // 只运行最近一批迁移 php artisan migrate:fresh // 删除所有表后重建（危险！） php artisan migrate:refresh // 回滚所有迁移后再运行 // 回滚 php artisan migrate:rollback // 回滚最后一批 php artisan migrate:rollback --step=3 // 回滚最后 3 批 // 检查状态 php artisan migrate:status

// 强制运行（生产环境通常需要确认） php artisan migrate --force

Seeder（数据填充）

// database/seeders/DatabaseSeeder.php
namespace Database\Seeders;
use App\Models\User;
use App\Models\Category;
use App\Models\Article;
use Illuminate\Database\Seeder;
class DatabaseSeeder extends Seeder
{
    public function run(): void
    {
        $this->call([
            CategorySeeder::class,
            UserSeeder::class,
            ArticleSeeder::class,
        ]);
    }
}
// database/seeders/CategorySeeder.php
namespace Database\Seeders;
use App\Models\Category;
use Illuminate\Database\Seeder;
class CategorySeeder extends Seeder
{
    public function run(): void
    {
        $categories = [
            ["name" => "PHP", "slug" => "php"],
            ["name" => "Laravel", "slug" => "laravel"],
            ["name" => "Vue.js", "slug" => "vuejs"],
            ["name" => "Docker", "slug" => "docker"],
            ["name" => "数据库", "slug" => "database"],
        ];
foreach ($categories as $category) {
            Category::create($category);
        }
    }
}
// database/seeders/ArticleSeeder.php
namespace Database\Seeders;
use App\Models\Article;
use App\Models\User;
use App\Models\Category;
use Illuminate\Database\Seeder;
class ArticleSeeder extends Seeder
{
    public function run(): void
    {
        $users = User::all();
        $categories = Category::all();
foreach (range(1, 50) as $i) {
            Article::create([
                "user_id" => $users->random()->id,
                "category_id" => $categories->random()->id,
                "title" => "示例文章标题 $i - " . fake()->sentence(),
                "slug" => "article-$i-" . fake()->unique()->slug(),
                "content" => fake()->paragraphs(5, true),
                "is_published" => fake()->boolean(80),  // 80% 概率发布
                "views" => fake()->numberBetween(0, 10000),
            ]);
        }
    }
}
// 运行 seeder
php artisan db:seed
php artisan db:seed --class=CategorySeeder
php artisan db:seed --class=CategorySeeder --force

Factory（工厂）

// database/factories/ArticleFactory.php
namespace Database\Factories;
use App\Models\Article;
use App\Models\User;
use App\Models\Category;
use Illuminate\Database\Eloquent\Factories\Factory;
class ArticleFactory extends Factory
{
    protected $model = Article::class;
public function definition(): array
    {
        return [
            "user_id" => User::factory(),              // 自动创建关联用户
            "category_id" => Category::factory(),
            "title" => $this->faker->sentence(6),
            "slug" => $this->faker->unique()->slug(),
            "content" => $this->faker->paragraphs(5, true),
            "excerpt" => $this->faker->sentence(),
            "is_published" => true,
            "views" => $this->faker->numberBetween(0, 10000),
            "published_at" => $this->faker->dateTimeBetween("-1 year"),
        ];
    }
// 状态方法
    public function draft()
    {
        return $this->state(fn (array $attributes) => [
            "is_published" => false,
            "published_at" => null,
        ]);
    }
public function featured()
    {
        return $this->state(fn (array $attributes) => [
            "views" => 10000,
        ]);
    }
}
// 使用 Factory
use App\Models\Article;
// 创建 1 篇
$article = Article::factory()->create();
// 创建 10 篇
$articles = Article::factory()->count(10)->create();
// 创建 5 篇草稿
$drafts = Article::factory()->count(5)->draft()->create();
// 创建带关联的
$article = Article::factory()->for(User::factory())->create();

常见问题

Q: migrate:fresh 和 migrate:refresh 有什么区别？
A：migrate:fresh 直接删除所有表后重新创建，不运行 down() 方法；migrate:refresh 运行所有迁移的 down() 再 up()。两个都会丢失数据，生产环境禁用。

Q: 迁移文件中的 foreignId 和单独定义 index 有什么区别？
A：foreignId() 会自动创建外键约束（BEFORE/AFTER SQL），同时在外键字段上建索引。如果用 $table->unsignedBigInteger("user_id") 则需手动加索引。
Q: Seeder 和 Factory 哪个更好？
A：Seeder 适合创建固定的初始数据（如管理员账号、默认分类）；Factory 适合批量生成随机测试数据。两者配合使用效果最佳。

Q: 已有数据的表想加索引会影响线上吗？
A：会。ALTER TABLE 加索引会锁表（InnoDB 大表可能锁几秒到几分钟）。生产环境建议使用 pt-online-schema-change 或 gh-ost 工具进行在线 DDL 操作。