Database Design Multiple Choice Let us apply what we have learned in class. We h

Question

Database Design Multiple Choice

Let us apply what we have learned in class. We have the following relational schema: Please normalize the above relational schema, so that the new design is a correct database schema that will replace the above design and will conform to 3NF. After that, please answer the following question. According to the new design that achieves 3NF, which of the following statement is FALSE? (a) One of the relations in the new schema is: PATIENT (PatientID. PatientName) (b) One of the relations in the new schema is: Medicine (MedName, ShelfLife, Dosage) (c) One of the relations in the new schema is: Prescription (MedName, PatientID, PresecriptionPatem NoOfRefills, Dosage) (d) The new design that achieves 3NF without losing any original information has a total of 3 tables. (e) All of (a) through (d) are TRUE.

Explanation / Answer

From the diagram below are the functional dependencies that are inferred

PATIENTID Medname PrescriptionDate -> Shelflife NoOfRefills PatientName Dosage

MedName-> ShelfLife

PatientID->PatientName

to acheive 3NF it should not posses partial dependency and transitive dependency

PatientID->PatientName ---- cause of partial dependency so new table is created using the attributes in the functional dependency

MedName-> ShelfLife --- cause of partial dependency so new table is created

so below will be the new tables

(PATIENTID,PatientName)   

(Medname,Shelflife )

(PATIENTID,Medname,PrescriptionDate ,NoOfRefills, Dosage)

so above three tables will be created now which makes only b wrong

For D option there is no loss of information as if you see any two relations or tables they must have a common attribute which must be a primary key in one table , so all the three have a common attribute which is a primary key so it will not lose any information or Loss less join

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