Database: Migrations
Introduction
Migrations are like version control for your database, allowing your team to easily modify and share the application's database schema. Migrations are typically paired with Laravel's schema builder to easily build your application's database schema. If you have ever had to tell a teammate to manually add a column to their local database schema, you've faced the problem that database migrations solve.
The Laravel Schema
facade provides database agnostic support for creating and manipulating tables across all of Laravel's supported database systems.
Generating Migrations
To create a migration, use the make:migration
Artisan command:
php artisan make:migration create_users_table
The new migration will be placed in your database/migrations
directory. Each migration file name contains a timestamp which allows Laravel to determine the order of the migrations.
The --table
and --create
options may also be used to indicate the name of the table and whether the migration will be creating a new table. These options simply pre-fill the generated migration stub file with the specified table:
php artisan make:migration create_users_table --create=users php artisan make:migration add_votes_to_users_table --table=users
If you would like to specify a custom output path for the generated migration, you may use the --path
option when executing the make:migration
command. The given path should be relative to your application's base path.
Migration Structure
A migration class contains two methods: up
and down
. The up
method is used to add new tables, columns, or indexes to your database, while the down
method should simply reverse the operations performed by the up
method.
Within both of these methods you may use the Laravel schema builder to expressively create and modify tables. To learn about all of the methods available on the Schema
builder, check out its documentation. For example, this migration example creates a flights
table:
<?php use Illuminate\Support\Facades\Schema; use Illuminate\Database\Schema\Blueprint; use Illuminate\Database\Migrations\Migration; class CreateFlightsTable extends Migration { /** * Run the migrations. * * @return void */ public function up() { Schema::create('flights', function (Blueprint $table) { $table->increments('id'); $table->string('name'); $table->string('airline'); $table->timestamps(); }); } /** * Reverse the migrations. * * @return void */ public function down() { Schema::drop('flights'); } }
Running Migrations
To run all of your outstanding migrations, execute the migrate
Artisan command:
php artisan migrate
If you are using the Homestead virtual machine, you should run this command from within your virtual machine.
Forcing Migrations To Run In Production
Some migration operations are destructive, which means they may cause you to lose data. In order to protect you from running these commands against your production database, you will be prompted for confirmation before the commands are executed. To force the commands to run without a prompt, use the --force
flag:
php artisan migrate --force
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