Database: Getting Started
- Introduction
- Running SQL Queries
- Database Transactions
- Connecting to the Database CLI
- Inspecting Your Databases
- Monitoring Your Databases
Introduction
Almost every modern web application interacts with a database. Laravel makes interacting with databases extremely simple across a variety of supported databases using raw SQL, a fluent query builder, and the Eloquent ORM. Currently, Laravel provides first-party support for five databases:
- MariaDB 10.3+ (Version Policy)
- MySQL 5.7+ (Version Policy)
- PostgreSQL 10.0+ (Version Policy)
- SQLite 3.26.0+
- SQL Server 2017+ (Version Policy)
Additionally, MongoDB is supported via the mongodb/laravel-mongodb
package, which is officially maintained by MongoDB. Check out the Laravel MongoDB documentation for more information.
Configuration
The configuration for Laravel's database services is located in your application's config/database.php
configuration file. In this file, you may define all of your database connections, as well as specify which connection should be used by default. Most of the configuration options within this file are driven by the values of your application's environment variables. Examples for most of Laravel's supported database systems are provided in this file.
By default, Laravel's sample environment configuration is ready to use with Laravel Sail, which is a Docker configuration for developing Laravel applications on your local machine. However, you are free to modify your database configuration as needed for your local database.
SQLite Configuration
SQLite databases are contained within a single file on your filesystem. You can create a new SQLite database using the touch
command in your terminal: touch database/database.sqlite
. After the database has been created, you may easily configure your environment variables to point to this database by placing the absolute path to the database in the DB_DATABASE
environment variable:
DB_CONNECTION=sqliteDB_DATABASE=/absolute/path/to/database.sqlite
By default, foreign key constraints are enabled for SQLite connections. If you would like to disable them, you should set the DB_FOREIGN_KEYS
environment variable to false
:
DB_FOREIGN_KEYS=false
If you use the Laravel installer to create your Laravel application and select SQLite as your database, Laravel will automatically create a database/database.sqlite
file and run the default database migrations for you.
Microsoft SQL Server Configuration
To use a Microsoft SQL Server database, you should ensure that you have the sqlsrv
and pdo_sqlsrv
PHP extensions installed as well as any dependencies they may require such as the Microsoft SQL ODBC driver.
Configuration Using URLs
Typically, database connections are configured using multiple configuration values such as host
, database
, username
, password
, etc. Each of these configuration values has its own corresponding environment variable. This means that when configuring your database connection information on a production server, you need to manage several environment variables.
Some managed database providers such as AWS and Heroku provide a single database "URL" that contains all of the connection information for the database in a single string. An example database URL may look something like the following:
mysql://root:[email protected]/forge?charset=UTF-8
These URLs typically follow a standard schema convention:
driver://username:password@host:port/database?options
For convenience, Laravel supports these URLs as an alternative to configuring your database with multiple configuration options. If the url
(or corresponding DB_URL
environment variable) configuration option is present, it will be used to extract the database connection and credential information.
Read and Write Connections
Sometimes you may wish to use one database connection for SELECT statements, and another for INSERT, UPDATE, and DELETE statements. Laravel makes this a breeze, and the proper connections will always be used whether you are using raw queries, the query builder, or the Eloquent ORM.
To see how read / write connections should be configured, let's look at this example:
'mysql' => [ 'read' => [ 'host' => [ '192.168.1.1', '196.168.1.2', ], ], 'write' => [ 'host' => [ '196.168.1.3', ], ], 'sticky' => true, 'database' => env('DB_DATABASE', 'laravel'), 'username' => env('DB_USERNAME', 'root'), 'password' => env('DB_PASSWORD', ''), 'unix_socket' => env('DB_SOCKET', ''), 'charset' => env('DB_CHARSET', 'utf8mb4'), 'collation' => env('DB_COLLATION', 'utf8mb4_unicode_ci'), 'prefix' => '', 'prefix_indexes' => true, 'strict' => true, 'engine' => null, 'options' => extension_loaded('pdo_mysql') ? array_filter([ PDO::MYSQL_ATTR_SSL_CA => env('MYSQL_ATTR_SSL_CA'), ]) : [],],
Note that three keys have been added to the configuration array: read
, write
and sticky
. The read
and write
keys have array values containing a single key: host
. The rest of the database options for the read
and write
connections will be merged from the main mysql
configuration array.
You only need to place items in the read
and write
arrays if you wish to override the values from the main mysql
array. So, in this case, 192.168.1.1
will be used as the host for the "read" connection, while 192.168.1.3
will be used for the "write" connection. The database credentials, prefix, character set, and all other options in the main mysql
array will be shared across both connections. When multiple values exist in the host
configuration array, a database host will be randomly chosen for each request.
The sticky
Option
The sticky
option is an optional value that can be used to allow the immediate reading of records that have been written to the database during the current request cycle. If the sticky
option is enabled and a "write" operation has been performed against the database during the current request cycle, any further "read" operations will use the "write" connection. This ensures that any data written during the request cycle can be immediately read back from the database during that same request. It is up to you to decide if this is the desired behavior for your application.
Running SQL Queries
Once you have configured your database connection, you may run queries using the DB
facade. The DB
facade provides methods for each type of query: select
, update
, insert
, delete
, and statement
.
Running a Select Query
To run a basic SELECT query, you may use the select
method on the DB
facade:
<?php namespace App\Http\Controllers; use App\Http\Controllers\Controller;use Illuminate\Support\Facades\DB;use Illuminate\View\View; class UserController extends Controller{ /** * Show a list of all of the application's users. */ public function index(): View { $users = DB::select('select * from users where active = ?', [1]); return view('user.index', ['users' => $users]); }}
The first argument passed to the select
method is the SQL query, while the second argument is any parameter bindings that need to be bound to the query. Typically, these are the values of the where
clause constraints. Parameter binding provides protection against SQL injection.
The select
method will always return an array
of results. Each result within the array will be a PHP stdClass
object representing a record from the database:
use Illuminate\Support\Facades\DB; $users = DB::select('select * from users'); foreach ($users as $user) { echo $user->name;}
Selecting Scalar Values
Sometimes your database query may result in a single, scalar value. Instead of being required to retrieve the query's scalar result from a record object, Laravel allows you to retrieve this value directly using the scalar
method:
$burgers = DB::scalar( "select count(case when food = 'burger' then 1 end) as burgers from menu");
Selecting Multiple Result Sets
If your application calls stored procedures that return multiple result sets, you may use the selectResultSets
method to retrieve all of the result sets returned by the stored procedure:
[$options, $notifications] = DB::selectResultSets( "CALL get_user_options_and_notifications(?)", $request->user()->id);
Using Named Bindings
Instead of using ?
to represent your parameter bindings, you may execute a query using named bindings:
$results = DB::select('select * from users where id = :id', ['id' => 1]);
Running an Insert Statement
To execute an insert
statement, you may use the insert
method on the DB
facade. Like select
, this method accepts the SQL query as its first argument and bindings as its second argument:
use Illuminate\Support\Facades\DB; DB::insert('insert into users (id, name) values (?, ?)', [1, 'Marc']);
Running an Update Statement
The update
method should be used to update existing records in the database. The number of rows affected by the statement is returned by the method:
use Illuminate\Support\Facades\DB; $affected = DB::update( 'update users set votes = 100 where name = ?', ['Anita']);
Running a Delete Statement
The delete
method should be used to delete records from the database. Like update
, the number of rows affected will be returned by the method:
use Illuminate\Support\Facades\DB; $deleted = DB::delete('delete from users');
Running a General Statement
Some database statements do not return any value. For these types of operations, you may use the statement
method on the DB
facade:
DB::statement('drop table users');
Running an Unprepared Statement
Sometimes you may want to execute an SQL statement without binding any values. You may use the DB
facade's unprepared
method to accomplish this:
DB::unprepared('update users set votes = 100 where name = "Dries"');
Since unprepared statements do not bind parameters, they may be vulnerable to SQL injection. You should never allow user controlled values within an unprepared statement.
Implicit Commits
When using the DB
facade's statement
and unprepared
methods within transactions you must be careful to avoid statements that cause implicit commits. These statements will cause the database engine to indirectly commit the entire transaction, leaving Laravel unaware of the database's transaction level. An example of such a statement is creating a database table:
DB::unprepared('create table a (col varchar(1) null)');
Please refer to the MySQL manual for a list of all statements that trigger implicit commits.
Using Multiple Database Connections
If your application defines multiple connections in your config/database.php
configuration file, you may access each connection via the connection
method provided by the DB
facade. The connection name passed to the connection
method should correspond to one of the connections listed in your config/database.php
configuration file or configured at runtime using the config
helper:
use Illuminate\Support\Facades\DB; $users = DB::connection('sqlite')->select(/* ... */);
You may access the raw, underlying PDO instance of a connection using the getPdo
method on a connection instance:
$pdo = DB::connection()->getPdo();
Listening for Query Events
If you would like to specify a closure that is invoked for each SQL query executed by your application, you may use the DB
facade's listen
method. This method can be useful for logging queries or debugging. You may register your query listener closure in the boot
method of a service provider:
<?php namespace App\Providers; use Illuminate\Database\Events\QueryExecuted;use Illuminate\Support\Facades\DB;use Illuminate\Support\ServiceProvider; class AppServiceProvider extends ServiceProvider{ /** * Register any application services. */ public function register(): void { // ... } /** * Bootstrap any application services. */ public function boot(): void { DB::listen(function (QueryExecuted $query) { // $query->sql; // $query->bindings; // $query->time; // $query->toRawSql(); }); }}
Monitoring Cumulative Query Time
A common performance bottleneck of modern web applications is the amount of time they spend querying databases. Thankfully, Laravel can invoke a closure or callback of your choice when it spends too much time querying the database during a single request. To get started, provide a query time threshold (in milliseconds) and closure to the whenQueryingForLongerThan
method. You may invoke this method in the boot
method of a service provider:
<?php namespace App\Providers; use Illuminate\Database\Connection;use Illuminate\Support\Facades\DB;use Illuminate\Support\ServiceProvider;use Illuminate\Database\Events\QueryExecuted; class AppServiceProvider extends ServiceProvider{ /** * Register any application services. */ public function register(): void { // ... } /** * Bootstrap any application services. */ public function boot(): void { DB::whenQueryingForLongerThan(500, function (Connection $connection, QueryExecuted $event) { // Notify development team... }); }}
Database Transactions
You may use the transaction
method provided by the DB
facade to run a set of operations within a database transaction. If an exception is thrown within the transaction closure, the transaction will automatically be rolled back and the exception is re-thrown. If the closure executes successfully, the transaction will automatically be committed. You don't need to worry about manually rolling back or committing while using the transaction
method:
use Illuminate\Support\Facades\DB; DB::transaction(function () { DB::update('update users set votes = 1'); DB::delete('delete from posts');});
Handling Deadlocks
The transaction
method accepts an optional second argument which defines the number of times a transaction should be retried when a deadlock occurs. Once these attempts have been exhausted, an exception will be thrown:
use Illuminate\Support\Facades\DB; DB::transaction(function () { DB::update('update users set votes = 1'); DB::delete('delete from posts');}, 5);
Manually Using Transactions
If you would like to begin a transaction manually and have complete control over rollbacks and commits, you may use the beginTransaction
method provided by the DB
facade:
use Illuminate\Support\Facades\DB; DB::beginTransaction();
You can rollback the transaction via the rollBack
method:
DB::rollBack();
Lastly, you can commit a transaction via the commit
method:
DB::commit();
The DB
facade's transaction methods control the transactions for both the query builder and Eloquent ORM.
Connecting to the Database CLI
If you would like to connect to your database's CLI, you may use the db
Artisan command:
php artisan db
If needed, you may specify a database connection name to connect to a database connection that is not the default connection:
php artisan db mysql
Inspecting Your Databases
Using the db:show
and db:table
Artisan commands, you can get valuable insight into your database and its associated tables. To see an overview of your database, including its size, type, number of open connections, and a summary of its tables, you may use the db:show
command:
php artisan db:show
You may specify which database connection should be inspected by providing the database connection name to the command via the --database
option:
php artisan db:show --database=pgsql
If you would like to include table row counts and database view details within the output of the command, you may provide the --counts
and --views
options, respectively. On large databases, retrieving row counts and view details can be slow:
php artisan db:show --counts --views
In addition, you may use the following Schema
methods to inspect your database:
use Illuminate\Support\Facades\Schema; $tables = Schema::getTables();$views = Schema::getViews();$columns = Schema::getColumns('users');$indexes = Schema::getIndexes('users');$foreignKeys = Schema::getForeignKeys('users');
If you would like to inspect a database connection that is not your application's default connection, you may use the connection
method:
$columns = Schema::connection('sqlite')->getColumns('users');
Table Overview
If you would like to get an overview of an individual table within your database, you may execute the db:table
Artisan command. This command provides a general overview of a database table, including its columns, types, attributes, keys, and indexes:
php artisan db:table users
Monitoring Your Databases
Using the db:monitor
Artisan command, you can instruct Laravel to dispatch an Illuminate\Database\Events\DatabaseBusy
event if your database is managing more than a specified number of open connections.
To get started, you should schedule the db:monitor
command to run every minute. The command accepts the names of the database connection configurations that you wish to monitor as well as the maximum number of open connections that should be tolerated before dispatching an event:
php artisan db:monitor --databases=mysql,pgsql --max=100
Scheduling this command alone is not enough to trigger a notification alerting you of the number of open connections. When the command encounters a database that has an open connection count that exceeds your threshold, a DatabaseBusy
event will be dispatched. You should listen for this event within your application's AppServiceProvider
in order to send a notification to you or your development team:
use App\Notifications\DatabaseApproachingMaxConnections;use Illuminate\Database\Events\DatabaseBusy;use Illuminate\Support\Facades\Event;use Illuminate\Support\Facades\Notification; /** * Bootstrap any application services. */public function boot(): void{ Event::listen(function (DatabaseBusy $event) { ->notify(new DatabaseApproachingMaxConnections( $event->connectionName, $event->connections )); });}