DBMS QUIZ_THEORY_3

Which one of the following statements about normal forms is FALSE?

• BCNF is stricter than 3NF

• Lossless, dependency­preserving decomposition into 3NF is always possible

• Lossless, dependency­preserving decomposition into BCNF is always possible

• Any relation with two attributes is in BCNF

Which of the following concurrency control protocols ensure both conflict serialzability and freedom from deadlock : I. 2­phase locking

II. Time­stamp ordering

• I only

• II only

• Both I and II

• Neither I nor II

Given the basic ER and relational models, which of the following is INCORRECT?

• An attributes of an entity can have more that one value

• An attribute of an entity can be composite

• In a row of a relational table, an attribute can have more than one value

• In a row of a relational table, an attribute can have exactly one value or a NULL value

Which of the following is TRUE?

• Every relation in 2NF is also in BCNF

• A relation R is in 3NF if every non­prime attribute of R is fully functionally dependent on every key of R

• Every relation in BCNF is also in 3NF

• No relation can be in both BCNF and 3NF

Which of the following key is required in to handle the data when the encryption is applied to the data so that the unauthorised user cannot access the data?

• Primary key

• Authorised key

• Encryption key

• Decryption key

Which command is used to remove a relation from an SQL?

• Drop table

• Delete

• Purge

• Remove

______________ is a set of one or more attributes taken collectively to uniquely identify a record.

• Primary Key

• Foreign key

• Super key

• Candidate key

The DBMS acts as an interface between ________________ and ________________ of an enterprise-class system.

• Data and the DBMS

• Application and SQL

• Database application and the database

• The user and the software

What does an RDBMS consist of?

• Collection of Records

• Collection of Keys

• Collection of Tables

• Collection of Fields

Which of the following is a component of the DBMS?

• Data

• Data Languages

• Data Manager

• All of the above