Introduction
Migrations are like version control for your database, allowing your team to modify and share the application's database schema. Migrations are typically paired with Laravel's schema builder to 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.
">Tip!! Migration stubs may be customized using
The --table
and --create
options may also be used to indicate the name of the table and whether or not the migration will be creating a new table. These options 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 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, the following migration creates a flights
table:
<?php
use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;
class CreateFlightsTable extends Migration
{
/**
* Run the migrations.
*
* @return void
*/
public function up()
{
Schema::create('flights', function (Blueprint $table) {
$table->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
Note: Homestead virtual machine, you should run this command from within your virtual machine.
If you are using the
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
Rolling Back Migrations
To roll back the latest migration operation, you may use the rollback
command. This command rolls back the last "batch" of migrations, which may include multiple migration files:
php artisan migrate:rollback
You may roll back a limited number of migrations by providing the step
option to the rollback
command. For example, the following command will roll back the last five migrations:
php artisan migrate:rollback --step=5
The migrate:reset
command will roll back all of your application's migrations:
php artisan migrate:reset
Roll Back & Migrate Using A Single Command
The migrate:refresh
command will roll back all of your migrations and then execute the migrate
command. This command effectively re-creates your entire database:
php artisan migrate:refresh
// Refresh the database and run all database seeds...
php artisan migrate:refresh --seed
You may roll back & re-migrate a limited number of migrations by providing the step
option to the refresh
command. For example, the following command will roll back & re-migrate the last five migrations:
php artisan migrate:refresh --step=5
Drop All Tables & Migrate
The migrate:fresh
command will drop all tables from the database and then execute the migrate
command:
php artisan migrate:fresh
php artisan migrate:fresh --seed
Tables
Creating Tables
To create a new database table, use the create
method on the Schema
facade. The create
method accepts two arguments: the first is the name of the table, while the second is a Closure
which receives a Blueprint
object that may be used to define the new table:
Schema::create('users', function (Blueprint $table) {
$table->id();
});
When creating the table, you may use any of the schema builder's column methods to define the table's columns.
Checking For Table / Column Existence
You may check for the existence of a table or column using the hasTable
and hasColumn
methods:
if (Schema::hasTable('users')) {
//
}
if (Schema::hasColumn('users', 'email')) {
//
}
Database Connection & Table Options
If you want to perform a schema operation on a database connection that is not your default connection, use the connection
method:
Schema::connection('foo')->create('users', function (Blueprint $table) {
$table->id();
});
You may use the following commands on the schema builder to define the table's options:
Command | Description |
---|---|
$table->engine = 'InnoDB'; |
Specify the table storage engine (MySQL). |
$table->charset = 'utf8mb4'; |
Specify a default character set for the table (MySQL). |
$table->collation = 'utf8mb4_unicode_ci'; |
Specify a default collation for the table (MySQL). |
$table->temporary(); |
Create a temporary table (except SQL Server). |
Renaming / Dropping Tables
To rename an existing database table, use the rename
method:
Schema::rename($from, $to);
To drop an existing table, you may use the drop
or dropIfExists
methods:
Schema::drop('users');
Schema::dropIfExists('users');
Renaming Tables With Foreign Keys
Before renaming a table, you should verify that any foreign key constraints on the table have an explicit name in your migration files instead of letting Laravel assign a convention based name. Otherwise, the foreign key constraint name will refer to the old table name.
Columns
Creating Columns
The table
method on the Schema
facade may be used to update existing tables. Like the create
method, the table
method accepts two arguments: the name of the table and a Closure
that receives a Blueprint
instance you may use to add columns to the table:
Schema::table('users', function (Blueprint $table) {
$table->string('email');
});
Available Column Types
The schema builder contains a variety of column types that you may specify when building your tables:
Command | Description |
---|---|
$table->id(); |
Alias of $table->bigIncrements('id') . |
$table->foreignId('user_id'); |
Alias of $table->unsignedBigInteger('user_id') . |
$table->bigIncrements('id'); |
Auto-incrementing UNSIGNED BIGINT (primary key) equivalent column. |
$table->bigInteger('votes'); |
BIGINT equivalent column. |
$table->binary('data'); |
BLOB equivalent column. |
$table->boolean('confirmed'); |
BOOLEAN equivalent column. |
$table->char('name', 100); |
CHAR equivalent column with a length. |
$table->date('created_at'); |
DATE equivalent column. |
$table->dateTime('created_at', 0); |
DATETIME equivalent column with precision (total digits). |
$table->dateTimeTz('created_at', 0); |
DATETIME (with timezone) equivalent column with precision (total digits). |
$table->decimal('amount', 8, 2); |
DECIMAL equivalent column with precision (total digits) and scale (decimal digits). |
$table->double('amount', 8, 2); |
DOUBLE equivalent column with precision (total digits) and scale (decimal digits). |
$table->enum('level', ['easy', 'hard']); |
ENUM equivalent column. |
$table->float('amount', 8, 2); |
FLOAT equivalent column with a precision (total digits) and scale (decimal digits). |
$table->geometry('positions'); |
GEOMETRY equivalent column. |
$table->geometryCollection('positions'); |
GEOMETRYCOLLECTION equivalent column. |
$table->increments('id'); |
Auto-incrementing UNSIGNED INTEGER (primary key) equivalent column. |
$table->integer('votes'); |
INTEGER equivalent column. |
$table->ipAddress('visitor'); |
IP address equivalent column. |
$table->json('options'); |
JSON equivalent column. |
$table->jsonb('options'); |
JSONB equivalent column. |
$table->lineString('positions'); |
LINESTRING equivalent column. |
$table->longText('description'); |
LONGTEXT equivalent column. |
$table->macAddress('device'); |
MAC address equivalent column. |
$table->mediumIncrements('id'); |
Auto-incrementing UNSIGNED MEDIUMINT (primary key) equivalent column. |
$table->mediumInteger('votes'); |
MEDIUMINT equivalent column. |
$table->mediumText('description'); |
MEDIUMTEXT equivalent column. |
$table->morphs('taggable'); |
Adds taggable_id UNSIGNED BIGINT and taggable_type VARCHAR equivalent columns. |
$table->uuidMorphs('taggable'); |
Adds taggable_id CHAR(36) and taggable_type VARCHAR(255) UUID equivalent columns. |
$table->multiLineString('positions'); |
MULTILINESTRING equivalent column. |
$table->multiPoint('positions'); |
MULTIPOINT equivalent column. |
$table->multiPolygon('positions'); |
MULTIPOLYGON equivalent column. |
$table->nullableMorphs('taggable'); |
Adds nullable versions of morphs() columns. |
$table->nullableUuidMorphs('taggable'); |
Adds nullable versions of uuidMorphs() columns. |
$table->nullableTimestamps(0); |
Alias of timestamps() method. |
$table->point('position'); |
POINT equivalent column. |
$table->polygon('positions'); |
POLYGON equivalent column. |
$table->rememberToken(); |
Adds a nullable remember_token VARCHAR(100) equivalent column. |
$table->set('flavors', ['strawberry', 'vanilla']); |
SET equivalent column. |
$table->smallIncrements('id'); |
Auto-incrementing UNSIGNED SMALLINT (primary key) equivalent column. |
$table->smallInteger('votes'); |
SMALLINT equivalent column. |
$table->softDeletes('deleted_at', 0); |
Adds a nullable deleted_at TIMESTAMP equivalent column for soft deletes with precision (total digits). |
$table->softDeletesTz('deleted_at', 0); |
Adds a nullable deleted_at TIMESTAMP (with timezone) equivalent column for soft deletes with precision (total digits). |
$table->string('name', 100); |
VARCHAR equivalent column with a length. |
$table->text('description'); |
TEXT equivalent column. |
$table->time('sunrise', 0); |
TIME equivalent column with precision (total digits). |
$table->timeTz('sunrise', 0); |
TIME (with timezone) equivalent column with precision (total digits). |
$table->timestamp('added_on', 0); |
TIMESTAMP equivalent column with precision (total digits). |
$table->timestampTz('added_on', 0); |
TIMESTAMP (with timezone) equivalent column with precision (total digits). |
$table->timestamps(0); |
Adds nullable created_at and updated_at TIMESTAMP equivalent columns with precision (total digits). |
$table->timestampsTz(0); |
Adds nullable created_at and updated_at TIMESTAMP (with timezone) equivalent columns with precision (total digits). |
$table->tinyIncrements('id'); |
Auto-incrementing UNSIGNED TINYINT (primary key) equivalent column. |
$table->tinyInteger('votes'); |
TINYINT equivalent column. |
$table->unsignedBigInteger('votes'); |
UNSIGNED BIGINT equivalent column. |
$table->unsignedDecimal('amount', 8, 2); |
UNSIGNED DECIMAL equivalent column with a precision (total digits) and scale (decimal digits). |
$table->unsignedInteger('votes'); |
UNSIGNED INTEGER equivalent column. |
$table->unsignedMediumInteger('votes'); |
UNSIGNED MEDIUMINT equivalent column. |
$table->unsignedSmallInteger('votes'); |
UNSIGNED SMALLINT equivalent column. |
$table->unsignedTinyInteger('votes'); |
UNSIGNED TINYINT equivalent column. |
$table->uuid('id'); |
UUID equivalent column. |
$table->year('birth_year'); |
YEAR equivalent column. |
Column Modifiers
In addition to the column types listed above, there are several column "modifiers" you may use while adding a column to a database table. For example, to make the column "nullable", you may use the nullable
method:
Schema::table('users', function (Blueprint $table) {
$table->string('email')->nullable();
});
The following list contains all available column modifiers. This list does not include the index modifiers:
Modifier | Description |
---|---|
->after('column') |
Place the column "after" another column (MySQL) |
->autoIncrement() |
Set INTEGER columns as auto-increment (primary key) |
->charset('utf8mb4') |
Specify a character set for the column (MySQL) |
->collation('utf8mb4_unicode_ci') |
Specify a collation for the column (MySQL/PostgreSQL/SQL Server) |
->comment('my comment') |
Add a comment to a column (MySQL/PostgreSQL) |
->default($value) |
Specify a "default" value for the column |
->first() |
Place the column "first" in the table (MySQL) |
->nullable($value = true) |
Allows (by default) NULL values to be inserted into the column |
->storedAs($expression) |
Create a stored generated column (MySQL) |
->unsigned() |
Set INTEGER columns as UNSIGNED (MySQL) |
->useCurrent() |
Set TIMESTAMP columns to use CURRENT_TIMESTAMP as default value |
->virtualAs($expression) |
Create a virtual generated column (MySQL) |
->generatedAs($expression) |
Create an identity column with specified sequence options (PostgreSQL) |
->always() |
Defines the precedence of sequence values over input for an identity column (PostgreSQL) |
Default Expressions
The default
modifier accepts a value or an \Illuminate\Database\Query\Expression
instance. Using an Expression
instance will prevent wrapping the value in quotes and allow you to use database specific functions. One situation where this is particularly useful is when you need to assign default values to JSON columns:
<?php
use Illuminate\Support\Facades\Schema;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Database\Query\Expression;
use Illuminate\Database\Migrations\Migration;
class CreateFlightsTable extends Migration
{
/**
* Run the migrations.
*
* @return void
*/
public function up()
{
Schema::create('flights', function (Blueprint $table) {
$table->id();
$table->json('movies')->default(new Expression('(JSON_ARRAY())'));
$table->timestamps();
});
}
}
Note:
Support for default expressions depends on your database driver, database version, and the field type. Please refer to the appropriate documentation for compatibility. Also note that using database specific functions may tightly couple you to a specific driver.
Modifying Columns
Prerequisites
Before modifying a column, be sure to add the doctrine/dbal
dependency to your composer.json
file. The Doctrine DBAL library is used to determine the current state of the column and create the SQL queries needed to make the required adjustments:
composer require doctrine/dbal
Updating Column Attributes
The change
method allows you to modify type and attributes of existing columns. For example, you may wish to increase the size of a string
column. To see the change
method in action, let's increase the size of the name
column from 25 to 50:
Schema::table('users', function (Blueprint $table) {
$table->string('name', 50)->change();
});
We could also modify a column to be nullable:
Schema::table('users', function (Blueprint $table) {
$table->string('name', 50)->nullable()->change();
});
Note:
Only the following column types can be "changed": bigInteger, binary, boolean, date, dateTime, dateTimeTz, decimal, integer, json, longText, mediumText, smallInteger, string, text, time, unsignedBigInteger, unsignedInteger, unsignedSmallInteger and uuid.
Renaming Columns
To rename a column, you may use the renameColumn
method on the schema builder. Before renaming a column, be sure to add the doctrine/dbal
dependency to your composer.json
file:
Schema::table('users', function (Blueprint $table) {
$table->renameColumn('from', 'to');
});
Note:
Renaming any column in a table that also has a column of typeenum
is not currently supported.
Dropping Columns
To drop a column, use the dropColumn
method on the schema builder. Before dropping columns from a SQLite database, you will need to add the doctrine/dbal
dependency to your composer.json
file and run the composer update
command in your terminal to install the library:
Schema::table('users', function (Blueprint $table) {
$table->dropColumn('votes');
});
You may drop multiple columns from a table by passing an array of column names to the dropColumn
method:
Schema::table('users', function (Blueprint $table) {
$table->dropColumn(['votes', 'avatar', 'location']);
});
Note:
Dropping or modifying multiple columns within a single migration while using a SQLite database is not supported.
Available Command Aliases
Command | Description |
---|---|
$table->dropMorphs('morphable'); |
Drop the morphable_id and morphable_type columns. |
$table->dropRememberToken(); |
Drop the remember_token column. |
$table->dropSoftDeletes(); |
Drop the deleted_at column. |
$table->dropSoftDeletesTz(); |
Alias of dropSoftDeletes() method. |
$table->dropTimestamps(); |
Drop the created_at and updated_at columns. |
$table->dropTimestampsTz(); |
Alias of dropTimestamps() method. |
Indexes
Creating Indexes
The Laravel schema builder supports several types of indexes. The following example creates a new email
column and specifies that its values should be unique. To create the index, we can chain the unique
method onto the column definition:
$table->string('email')->unique();
Alternatively, you may create the index after defining the column. For example:
$table->unique('email');
You may even pass an array of columns to an index method to create a compound (or composite) index:
$table->index(['account_id', 'created_at']);
Laravel will automatically generate an index name based on the table, column names, and the index type, but you may pass a second argument to the method to specify the index name yourself:
$table->unique('email', 'unique_email');
Available Index Types
Each index method accepts an optional second argument to specify the name of the index. If omitted, the name will be derived from the names of the table and column(s) used for the index, as well as the index type.
Command | Description |
---|---|
$table->primary('id'); |
Adds a primary key. |
$table->primary(['id', 'parent_id']); |
Adds composite keys. |
$table->unique('email'); |
Adds a unique index. |
$table->index('state'); |
Adds a plain index. |
$table->spatialIndex('location'); |
Adds a spatial index. (except SQLite) |
Index Lengths & MySQL / MariaDB
Laravel uses the utf8mb4
character set by default, which includes support for storing "emojis" in the database. If you are running a version of MySQL older than the 5.7.7 release or MariaDB older than the 10.2.2 release, you may need to manually configure the default string length generated by migrations in order for MySQL to create indexes for them. You may configure this by calling the Schema::defaultStringLength
method within your AppServiceProvider
:
use Illuminate\Support\Facades\Schema;
/**
* Bootstrap any application services.
*
* @return void
*/
public function boot()
{
Schema::defaultStringLength(191);
}
Alternatively, you may enable the innodb_large_prefix
option for your database. Refer to your database's documentation for instructions on how to properly enable this option.
Renaming Indexes
To rename an index, you may use the renameIndex
method. This method accepts the current index name as its first argument and the desired new name as its second argument:
$table->renameIndex('from', 'to')
Dropping Indexes
To drop an index, you must specify the index's name. By default, Laravel automatically assigns an index name based on the table name, the name of the indexed column, and the index type. Here are some examples:
Command | Description |
---|---|
$table->dropPrimary('users_id_primary'); |
Drop a primary key from the "users" table. |
$table->dropUnique('users_email_unique'); |
Drop a unique index from the "users" table. |
$table->dropIndex('geo_state_index'); |
Drop a basic index from the "geo" table. |
$table->dropSpatialIndex('geo_location_spatialindex'); |
Drop a spatial index from the "geo" table (except SQLite). |
If you pass an array of columns into a method that drops indexes, the conventional index name will be generated based on the table name, columns and key type:
Schema::table('geo', function (Blueprint $table) {
$table->dropIndex(['state']); // Drops index 'geo_state_index'
});
Foreign Key Constraints
Laravel also provides support for creating foreign key constraints, which are used to force referential integrity at the database level. For example, let's define a user_id
column on the posts
table that references the id
column on a users
table:
Schema::table('posts', function (Blueprint $table) {
$table->unsignedBigInteger('user_id');
$table->foreign('user_id')->references('id')->on('users');
});
Since this syntax is rather verbose, Laravel provides additional, terser methods that use convention to provide a better developer experience. The example above could be written like so:
Schema::table('posts', function (Blueprint $table) {
$table->foreignId('user_id')->constrained();
});
The foreignId
method is an alias for unsignedBigInteger
while the constrained
method will use convention to determine the table and column name being referenced. If your table name does not match the convention, you may specify the table name by passing it as an argument to the constrained
method:
Schema::table('posts', function (Blueprint $table) {
$table->foreignId('user_id')->constrained('users');
});
You may also specify the desired action for the "on delete" and "on update" properties of the constraint:
$table->foreignId('user_id')
->constrained()
->onDelete('cascade');
Any additional column modifiers must be called before constrained
:
$table->foreignId('user_id')
->nullable()
->constrained();
To drop a foreign key, you may use the dropForeign
method, passing the foreign key constraint to be deleted as an argument. Foreign key constraints use the same naming convention as indexes, based on the table name and the columns in the constraint, followed by a "_foreign" suffix:
$table->dropForeign('posts_user_id_foreign');
Alternatively, you may pass an array containing the column name that holds the foreign key to the dropForeign
method. The array will be automatically converted using the constraint name convention used by Laravel's schema builder:
$table->dropForeign(['user_id']);
You may enable or disable foreign key constraints within your migrations by using the following methods:
Schema::enableForeignKeyConstraints();
Schema::disableForeignKeyConstraints();
Note: enable foreign key support in your database configuration before attempting to create them in your migrations. In addition, SQLite only supports foreign keys upon creation of the table and not when tables are altered.
SQLite disables foreign key constraints by default. When using SQLite, make sure to