MySQL best approach for db normalising, relationships and foreign keys

Question

There is an username/password verification step first then the database has following structure

^ is primary key

* uses foreign key


1.StudentDetails table
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Answer 1

option 1:
enter the adress data first, and use that id when createing the row in StudentDetails

option 2:
change the field StudentDetails.Address so its allow NULL valus, enter the StudentDetails, then the adress, and then update the StudentDetails.Address