DBMS End Term: 28 April 2024, Set QDB1 (January 2024 term)

Let us consider the following statistics for searching a condition within a given relation.

• Number of blocks containing record of the relation $(b) = 400$
• Time to transfer one block $(t_b) = 0.6$ milliseconds
• Time for one seek $(t_s) = 8$ milliseconds

What will be the average cost of selection query on a key attribute using linear search file scan?

Consider the relational schema:

prescription(doctor_id, doctor_name, patient_id, patient_name, medicine_id, medicine_name), where the domains of all the attributes consist of atomic values. Consider the following FDs for the relation prescription .

• $doctor\_id \rightarrow doctor\_name$,
• $patient\_id \rightarrow patient\_name$,
• $medicine\_id \rightarrow medicine\_name$,
• $doctor\_id \rightarrow\rightarrow patient\_id$,
• $doctor\_id \rightarrow\rightarrow medicine\_id$

From among the decompositions given, identify the one that is in 4NF.