# Database MCQ - ER-model & Relational Model

56:

Consider a relational table with a single record for each registered student with the following attributes.
1. Registration Num: Unique registration of each registered student.
2. UID Unique identity number, unique at the national level for each citizen.
3. Name: Name of the student.
4. BanIcAccount Num: Unique account number at the bank. A student can have multiple account or joint accounts.                This attribute stores the primary account number.
5. Hostel_Room: Room number ofhe hostel.
Which ofthe following option is INCORRECT?

 A. BankAccount Num is a candidate key. B. Registration Num can be a primary key C. UID is candidate key if all students are from same country. D. If S is a superkey such that S ∩ UID is NULL then S  ∪ UID is also a superkey. Answer Report Discuss Option: A Explanation : Click on Discuss to view users comments. Write your comments here:
57:

The following functional dependencies hold for relation R(A, B, C) and S(B, D, E) B —> A, A —> C , the relation R contains 200 tuples and relation S contains 100 tuples. What is maximum number of tuples possibles in natural join R  and S ?

 A. 100 B. 200 C. 300 D. 400 Answer Report Discuss Option: A Explanation : Click on Discuss to view users comments. Write your comments here:
58:

Which structure is the hierarchical model based

 A. Tree B. Graph C. Linked List D. None of the above Answer Report Discuss Option: A Explanation : Click on Discuss to view users comments. Write your comments here:
59:

In the relational model, the number of attributes and number of tuples iri a relation are termed as __________and ______________respectively

 A. Cardinality, domain B. Degree, cardinality C. Domain degree D. Cardinality, degree Answer Report Discuss Option: B Explanation : Click on Discuss to view users comments. Write your comments here:
60:

In domain relational calculus we create a variable for every

 A. Row B. Column C. Table D. None of the above Answer Report Discuss Option: B Explanation : Click on Discuss to view users comments. Write your comments here:

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