If you forgot the password to your MySQL database user, then you must create a new username with a new password.
With the newly setup username and password, only then you can assign to the MySQL database.
Do not worry.
This procedure will not erase or change any of the data in your database.
Create My SQL New Username And Password
Let's do it now.
1. Log in to your cPanel.
2. Click on the "MySQL Databases" icon listed under the "DATABASES" section.
3. It will open a new page.
4. Scroll down until you see "MySQL Users" and "Add New User".
5. Under "Add New User", type in a username in the space provided.
Note: The username must be 7 letters or shorter.
6. Next type in a password in the "Password" box.
7. Retype the password in the Password (Again) box.
8. Finally click on the "Create User" button.
9. That's all.