In Laravel, how do I retrieve a random user_id from the Users table for Model Factory seeding data generation?

Try the below.

use App\User; // Assuming this is your User Model class with namespace.

$factory->define(App\Reply::class, function (Faker\Generator $faker) {
  return [
    'thread_id' => 1,
    'user_id' => User::all()->random()->id,
    'body' => $faker->paragraph
  ];
});

Remember that this gets all the user data from your table and then choses an id randomly. So if your table has huge amount of data, it is not recommended. Instead, in your Test Case, you can create a new User (via its own factory) and assign the id to the Reply object generated from the above factory.

Alternately, you can query for a specific user in the above factory definition.

'user_id' => User::where('username', 'like', '[email protected]')->get()->random()->id

If you have a test user set up in your DB this will avoid pulling all the user data.

Any class that extends Illuminate\Database\Eloquent\Model will be able to do this:

User::inRandomOrder()->first()

Or to get a Collection of 3 items:

User::inRandomOrder()->limit(3)->get()

This might be more efficient than using User::all()->first(), which ought to first query all Users.

Your IDE (like PhpStorm) will probably be wildly confused that this is an option though.

Also see: Laravel - Eloquent or Fluent random row

It does not work like that 'user_id':

User::all()->random()->user_id

But that's how it works:

User::all()->random()->id