How do you create and run migrations in Laravel?

In Laravel, migrations are a way to manage your database schema. They allow you to create and modify database tables and fields programmatically using PHP code, which is particularly useful for version control and team collaboration.

Here’s how to create and run migrations in Laravel:

1. Creating a Migration

You can create a migration using the artisan command. For example, to create a migration for a users table:

php artisan make:migration create_users_table

This command will generate a migration file in the database/migrations directory with a timestamped filename.

2. Editing the Migration

Once the migration is created, you can define the structure of your table within the up method. Laravel uses the Schema builder to define the structure of the table.

Example of a migration file:

<?php

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

class CreateUsersTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('users', function (Blueprint $table) {
            $table->id(); // Creates an auto-incrementing primary key
            $table->string('name');
            $table->string('email')->unique();
            $table->timestamp('email_verified_at')->nullable();
            $table->string('password');
            $table->rememberToken();
            $table->timestamps(); // Creates created_at and updated_at columns
        });
    }

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

• up method: Defines the actions to be performed when the migration is run (usually creating or modifying a table).
• down method: Defines the actions to reverse the migration (typically dropping the table or reverting modifications).

3. Running Migrations

To run all the pending migrations, you use the following command:

php artisan migrate

This will execute all migrations that haven't been run yet and apply the changes to your database.

4. Rolling Back Migrations

If you want to revert the last batch of migrations, you can run:

php artisan migrate:rollback

This will undo the last migration. If you want to rollback all migrations, you can use:

php artisan migrate:reset

Or, to rollback and rerun all migrations:

php artisan migrate:refresh

5. Seeding Data (Optional)

After running migrations, you might also want to seed your database with some default data. You can do that by creating and running seeders using:

php artisan db:seed

Example Workflow:

1. Create a migration:

   php artisan make:migration create_posts_table
   

2. Edit the migration to define the structure of the posts table.

3. Run the migration to apply the changes to your database:

   php artisan migrate
   

4. If needed, roll back the migration:

   php artisan migrate:rollback