1. Initiate docker compose

   $ docker-compose up

2. Then enter into app container

   $ docker exec -it referralcode_main_1 sh

3. In the app container execute command below for creating db schema and relationship

   $ php artisan migrate

4. Then still in the app container execute command below for seeding database

   $ php artisan db:seed --class=UsersTableSeeder
   $ php artisan db:seed --class=OwnersTableSeeder
   $ php artisan db:seed --class=ReferralCodesTableSeeder

5. Then the API ready to use by using postman or curl in terminal as follows:

   curl --location --request GET 'http://localhost:8000/api/process' \
   --header 'Content-Type: application/json' \
   --data-raw '{
       "referralcode": "ABCD"
   }'

   API response:

   {
       "status": "Success",
       "message": null,
       "data": {
           "user": {
               "id": 1,
               "firstname": "John",
               "lastname": "Doe",
               "email": "Ysxx1m8d4G@yopmail.com",
               "created_at": "2022-05-30T08:57:52.000000Z",
               "updated_at": "2022-05-30T08:57:52.000000Z"
           },
           "owner": {
               "id": 1,
               "created_at": "2022-05-30T08:58:59.000000Z",
               "updated_at": "2022-05-30T08:58:59.000000Z",
               "user_id": 1
           },
           "referralcode": {
               "id": 2,
               "code": "ABCD",
               "created_at": "2022-05-30T08:59:11.000000Z",
               "updated_at": "2022-05-30T08:59:11.000000Z",
               "owner_id": 1
           }
       }
   }

ABCD
EFGH
IJKL

select u.*,  rc.code as referralcode
from users u 
left join owners o on o.user_id = u.id
left join referral_codes rc on rc.owner_id = o.id
where rc.code = 'ABCD'

Query result:

+----+-----------+----------+------------------------+---------------------+---------------------+--------------+
| id | firstname | lastname | email                  | created_at          | updated_at          | referralcode |
+----+-----------+----------+------------------------+---------------------+---------------------+--------------+
|  1 | John      | Doe      | Ysxx1m8d4G@yopmail.com | 2022-05-30 08:57:52 | 2022-05-30 08:57:52 | ABCD         |
+----+-----------+----------+------------------------+---------------------+---------------------+--------------+