The relational schema shown below is part of a hospital database. The primary keys are highlighted in bold. Patient ( patientNo , patName, patAddr, DOB) Ward ( wardNo , wardName, wardType, noOfBeds)...

The relational schema shown below is part of a hospital database. The primary keys are highlighted in bold.

Patient (patientNo, patName, patAddr, DOB)
Ward (wardNo, wardName, wardType, noOfBeds)
Contains (patientNo,wardNo,admissionDate)
Drug (drugNo, drugName, costPerUnit)
Prescribed (patientNo,drugNo, unitsPerDay,startDate, finishDate)

for CONTAINS nad PRESCRIBED table , which one is primary key and how to create table ?