== User Login

==== Actors: **Registered User (USER / ADMIN / INSTRUCTOR)**

**1.** Check if User Exists.”.

The system checks whether a user with the given email exists in the database.

{{{#!sql
SELECT id, password, role
FROM user_entity
WHERE email = :email;



}}}

**2.** Password Validation (Application Logic).

**#** The entered password is compared with the stored hashed password.

**#** If the password is invalid, the login process is stopped.

**#** If the password is valid, the process continues.


**3.** Load User Type Based on Role.

After successful authentication, the system loads the user type according to the role.

**#** If the role is USER:
{{{#!sql
SELECT id
FROM users
WHERE id = :userId;



}}}

**#** If the role is ADMIN:
{{{#!sql
SELECT id
FROM administrators
WHERE id = :userId;




}}}

**#** If the role is INSTRUCTOR:
{{{#!sql
SELECT id
FROM instructors
WHERE id = :userId;



}}}