Connect multiple databases dynamically in laravel

Question

I'm building an application which requires connecting 2 database. first one is static and another one is dynamic. config/database.php is like

'mysql' => 
array (
  'driver' => 'mysql',
  'host' => '127.0.0.1',
  'port' => '3306',
  'database' => 'blog',
  'username' => 'root',
  'password' => '',
  'unix_socket' => '',
  'charset' => 'utf8mb4',
  'collation' => 'utf8mb4_unicode_ci',
  'prefix' => '',
  'strict' => true,
  'engine' => NULL,
),
'business2' => 
array (
  'driver' => 'mysql',
  'host' => '127.0.0.1',
  'port' => '3306',
  'database' => 'blog2',
  'username' => 'root',
  'password' => '',
  'unix_socket' => '',
  'charset' => 'utf8mb4',
  'collation' => 'utf8mb4_unicode_ci',
  'prefix' => '',
  'strict' => true,
  'engine' => NULL,
),

and model code is like

Class  TableNewData extends Model
{
    protected $connection = 'business3';
    protected $table = 'table2_data';
    public function getData()
    {
        return $this->get()->toArray();
    }
}

I am able to connect multiple databases if I give static connection details but I am unable to connect database if I give dynamic connection details like

 $connection = Session::get()->connection;  

or

$connection=$_SESSION('connection');

What is the best way to connect multiple databases dynamically without effecting performance of application?

Answer 1

One way of changing the connection at runtime is to set the values via the config:

config(['database.connections.mysql' => [
    'driver'    => 'mysql',
    'host'      => env('DB_HOST', 'localhost'),
    'database'  => env('DB_DATABASE', 'my_database'),
    'username'  => env('DB_USERNAME', 'my_user'),
    'password'  => env('DB_PASSWORD', 'my_password'),
    'charset'   => 'utf8',
    'collation' => 'utf8_unicode_ci',
    'prefix'    => '',
    'strict'    => false,
]]);

This can be applied in a middleware to dynamically switch between tenant databases, for example.

You can also specify a connection via the DB facade:

DB::connection('mysql_2')->select(...);

Answer 2

I had the same problem as you. This blog can definitely help you out.

The Ultimate Guide for Laravel Multi Tenant with Multi Database

Here is how the config/database.php file looks like based on your situation. Since the second one is dynamic, there is no need to define the database.

'mysql' => [
        'driver' => 'mysql',
        'host' => env('DB_HOST', '127.0.0.1'),
        'port' => env('DB_PORT', '3306'),
        'database' => env('DB_DATABASE', 'blog'),
        'username' => env('DB_USERNAME', 'root'),
        'password' => env('DB_PASSWORD', 'password'),
        'unix_socket' => env('DB_SOCKET', ''),
        'charset' => 'utf8mb4',
        'collation' => 'utf8mb4_unicode_ci',
        'prefix' => '',
        'strict' => true,
        'engine' => 'InnoDB',
    ],
'business' => [
        'driver' => 'mysql',
        'host' => env('DB_HOST', '127.0.0.1'),
        'port' => env('DB_PORT', '3306'),
        'database' => '',
        'username' => env('DB_USERNAME', 'root'),
        'password' => env('DB_PASSWORD', 'password'),
        'unix_socket' => env('DB_SOCKET', ''),
        'charset' => 'utf8mb4',
        'collation' => 'utf8mb4_unicode_ci',
        'prefix' => '',
        'strict' => true,
        'engine' => 'InnoDB',
    ], 

Basically, set up a database helper function which connects to the database at runtime and then calls it in the right middleware.I just put the helper file at database/utilities/helpers.php

function connect($hostname, $username, $password, $database)
{
    // Erase the tenant connection, thus making Laravel get the default values all over again.
    DB::purge('business');
    // Make sure to use the database name we want to establish a connection.
    Config::set('database.connections.tenant.host', $hostname);
    Config::set('database.connections.tenant.database', $database);
    Config::set('database.connections.tenant.username', $username);
    Config::set('database.connections.tenant.password', $password);
    // Rearrange the connection data
    DB::reconnect('business');
    // Ping the database. This will throw an exception in case the database does not exists.
    Schema::connection('tenant')->getConnection()->reconnect();
}

Don't forget to tell the composer that the helper function can be used globally by adding those line into the composer.json file.

"autoload": {
    "classmap": [
        "database"
    ],
    "files":[
        "database/utilities/helpers.php"
    ],
    "psr-4": {
        "App\\": "app/"
    }
},

You also want to have static and dynamic models that should be extended to define which database connections to use.

class StaticModel extends Model
{
    protected $connection = 'mysql';
}
class DynamicModel extends Model
{
    protected $connection = 'business';
}

In the middleware set up the dynamic database connection according to the database name.

connect(getenv('DB_HOST'), getenv('DB_USERNAME'), getenv('DB_PASSWORD'), getenv('DB_SYMBOL') . $databasename);

Thus, you can use the model as normal but it has the dynamic database connections