Hi, I'm just starting to programm databases and I've found a problem with an example:
the db is for a lab so I made 3 tables, 1 for the pacient data and the other 2 for data of two different studies. Since one pacient can have either one of the studies or both, the table with the pacient's data must be related to the other two (in this case by a protocol number that serves as the primary key). The problem comes when I want to establish this relationship between the protocol field in the pacient table and the same field in the other two tables at the same time.
Is the design of the db wrong or this can be done?