Corvid login with query

Hi at all! i am new here,
i need help to create a login with corvid on wix, only the code for sign up user with their email and password but i create a database in which i put the code (my code to recognize clients) for every user, because i have a client with own code. and the system must check if this code exist in databse for create an account.
if anyone can help me THANK YOU SO MUCH!

Have you already seen this Wix tutorial for a members profile?
https://support.wix.com/en/article/corvid-tutorial-building-your-own-members-area

The code will check if there is already a member…
Query the Members collection to see if an item for the current user exists.
If there is no item for the current user, create one.

You will still need to crate your own login and signup lightboxes if you don’t wish to use the Wix default or custom signup/login forms.
https://support.wix.com/en/article/about-the-member-signup-form

If you do go down the Corvid option, then you need to make sure that you change your Member Signup options to suit your choice.
https://support.wix.com/en/article/corvid-enabling-custom-site-registration

You can also look at previous forum posts about this too.
https://www.wix.com/corvid/forum/community-discussion/checking-if-member-exists-in-members-privatemembersdata
https://www.wix.com/corvid/forum/community-discussion/prevent-contact-duplicates-in-custom-registration-1
https://www.wix.com/corvid/forum/community-discussion/prevent-contact-duplicates-in-custom-registration

Finally, Nayeli (Code Queen) has a great tutorial from late last year that might help you more too.
Wix Custom Registration to Check Existing User and Input Validation
https://www.totallycodable.com/wix/corvid/corvid-registration-code-check-existing-user-and-input-validation

thankss!