DBI_PT1

QN=17 (6831) What is a primary key? a. A primary key is the field(s) in a table that uniquely defines that table in a database b. A primary key is the field(s) in a table that is used to establishes a relationship between two tables c. A primary key is the field(s) in a table that uniquely defines the row in the table d. A primary key is the field(s) in a table that is used to establishes a relationship between two databases

c

QN=26 (7963) Given the relation schema R(A,B,C) and functional dependencies F = {AB-> C, B->A, C->B}. Which attribute(s) is/are prime? a. only A b. only B c. A and B d. B and C

d

QN=12 (6816) Data Definition language (DDL) is used to ...... a. query database and modify the database b. connect to database and query database c. declare database schemas d. All of the others

c

QN=6 (6798) Today, in a modern DBMS, the queries are parsed and optimized by a. all of the others b. execution engine c. buffer manager d. query compiler

d

QN=36 (7991) 3NFconcept is related to (choose 1 answer only): a. Atomic definition b. Full dependency definition c. Transitive dependency definition d. Super Key definition e. All of the others

e

QN=21 (6829) What is another term for a row in a relational table? a. Attribute b. Tuple c. Field d. Relation

b

QN=13 (6815) Which is the subset of SQL commands used to manipulate Database structures, including tables? a. DDL (Data Definition Language) b. DML (Data Manipulation Language) c. DCL (Data Control Language) d. All of the others

a

QN=15 (6823) "R(A,B,C,D)" is an example of: a. A schema b. A relation c. A relation instance d. A schema instance

a

QN=16 (6813) Which statement is used to remove a column named D from the relation R? a. ALTER TABLE R DROP COLUMN D; b. ALTER TABLE R DROP COLUMN D [DataType]; c. ALTER TABLE R DELETE COLUMN D; d. ALTER TABLE R DELETE COLUMN D [DataType];

a

QN=18 (6817) A ____ is a relation name, together with the attributes of that relation. a. schema b. database c. database instance d. schema instance

a

QN=19 (6822) Which statement is used to add a column named D into the relation R? a. ALTER TABLE R ADD D [DataType]; b. ALTER TABLE R ADD ATTRIBUTE D [DataType]; c. ALTER TABLE R ADD PROPERTY D [DataType];

a

QN=2 (6808) What is a database? a. A database is a collection of information that is organized so that it can easily be accessed, managed, and updated b. A database is a collection of data files c. A database is a collection of records d. A database is a collection of tuples

a

QN=24 (7962) What is a functional dependency? a. A functional dependency (A->B) occurs when the attribute A uniquely determines B b. A functional dependency (A->B) occurs when the attribute B uniquely determines A

a

QN=28 (7966) Suppose R is a relation with attributes A1, A2, A3, A4. The only key of R is {A1, A2}. So, how many super-keys do R have? a. 4 b. 8 c. 12 d. 16

a

QN=29 (7967) A set of attributes forms a ____ for a relation if we do not allow 2-tuples in a relation instance to have the same values in all that attributes a. Key b. Foreign Key c. Index Key d. Trigger Key

a

QN=31 (7979) The relation R(ABCD) has following FDs: {ACD -> B ; AC -> D ; D -> C ; AC -> B} Choose the correct statement about R: a. R is in 3NF b. R is in 2NF only, not higher c. R is in 1NF only, not higher d. None of the others

a

QN=34 (7976) Given a R(A,B,C,D) with the following FDs: AB->D BC->A AD->B CD->B AD->C Choose a correct statement about R: a. The FD set of R is not canonical and R is in BCNF b. The FD set of R is canonical and R is not in BCNF c. The FD set of R is not canonical and R is not in BCNF

a

QN=35 (7990) Consider the following functional dependencies a,b -> c,d e,g,h -> f,j a,c -> b,d p,q -> r,s e,f,g -> h,i s -> t f,g -> j q -> u g,h -> i Which of the following best describes the relation R(e,f,g,h,i,j)? a. R is in First Normal Form b. R is in Second Normal Form c. R is in Third Normal Form d. R is in Boyce Codd Normal Form

a

QN=37 (7985) Which of the following relations is in third normal form (3NF)? a. R(ABCD) with FD's: ACD -> B ; AC -> D ; D -> C ; AC -> B b. R(ABCD) with FD's: AB -> C ; ABD -> C ; ABC -> D ; AC -> D c. R(ABCD) with FD's: AB -> C ; BCD -> A ; D -> A ; B -> C

a

QN=42 (7995) How to eliminate anomalies when we design a database? a. We should decompose relation to eliminate anomalies b. We should join relations to eliminate anomalies c. We should union relations to eliminate anomalies d. None of the others

a

QN=43 (8003) Look at the following statements: (a) For any relation schema, there is a dependency-preserving decomposition into 3NF (b) For any relation schema, there is not dependency-preserving decomposition into 3NF (c) For any relation schema, there is dependency-preserving decomposition into BCNF (d) For some relation schema, there is not dependency-preserving decomposition into BCNF a. (a) and (d) are true b. (a) and (b) are true c. (a) and (c) are true d. (b) and (d) are true

a

QN=45 (8006) What is "normalization"? a. Normalizing data means eliminating redundant information from a table and organizing the data so that future changes to the table are easier b. Normalizing data means minimizing columns from a table and organizing the data so that future changes to the table will be made more quickly c. Normalizing data means removing columns from a table and organizing the data so that future changes to the table will be made more quickly d. Normalizing data means adding more columns to a table and organizing the data so that future changes to the table will be made more quickly

a

QN=8 (6800) What is the hierarchical data model? a. A hierarchical data model is a data model in which the data is organized into a tree-like structure b. A hierarchical data model is a data model in which the data is organized into a table-like structure c. A hierarchical data model is a data model in which the data is organized into a graph-like structure d. None of the others

a

QN=20 (6821) Which one of the following is NOT a DML command? a. DELETE b. GRANT c. INSERT d. UPDATE

b

QN=11 (6824) A ___ is a notation for describing the structure of the data in a database, along with the constraints on that data a. database management system b. data model c. data operation d. data manipulation

b

QN=22 (6811) The relational operator that adds all possible pairs of rows from two tables is known as the .... operator. a. union b. product c. join d. selection

b

QN=25 (7969) Consider a relation with schema R(A, B, C, D) and FD's BC -> D, D -> A, A -> B. Which of the following is the key of R? a. BD b. BC c. D d. AB

b

QN=32 (7981) Suppose we have a relation R(ABCD) with FD's: BC -> A ; AD -> C ; CD -> B ; BD -> C a. R is in BCNF b. R is not in BCNF c. All of the others d. None of the others

b

QN=38 (7977) The relation R(ABCD) has following FDs: { AB -> C ; ABD -> C ; ABC -> D ; AC -> D} Choose a correct statement about R? a. R is in 3NF b. R is not in 3NF c. R is in BCNF

b

QN=4 (6793) A ______ is a collection of programs that enables user to create and maintain databases. In other words, it is general-purpose software that provides the users with the processes of defining, constructing and manipulating the databases for various applications a. MSSQL b. DBMS c. DBS d. DB2

b

QN=41 (8004) What is the benefit of "de-normalization"? a. "de-normalization" has no benefit b. The main benefit of de-normalization is improved performance with simplified data retrieval (this is done by reduction in the number of joins needed for data processing) c. The main benefit of de-normalization is eliminating redundant information from a table and organizing the data so that future changes to the table are easier

b

QN=5 (6810) Today, the two important data models are: a. The semi-structured data model (including XML and related standards) and the network data model b. The relational data model (including object-relational extensions) and the semi-structured data model (including XML and related standards) c. The network data model and the flat file data model d. The flat file data model and the semi-structured data model (including XML and related standards)

b

QN=7 (6803) A ____ is a logically coherent collection of data with some inherent meaning, representing some aspect of real world and being designed, built and populated with data for a specific purpose a. Database Instance b. Database c. Schema d. Schema Instance

b

QN=9 (6806) A person who is responsible for the structure or schema of the database is called: a. an end user b. a database administrator c. a database analyst d. all of the others

b

QN=1 (6807) What is a graph database? a. A graph database is a database that uses tree structures with nodes to represent and store information b. A graph database is a database that uses table structures to represent and store information c. A graph database is a database that uses graph structures with nodes, edges and properties to represent and store information d. None of the others

c

QN=10 (6809) A database administrator (DBA) is a person that is also known by the title: a. Database Analyst b. Database Tuner c. Database Coordinator or Database Programmer d. Database Modeller

c

QN=23 (7956) Let R(ABCDEFGH) satisfies the following functional dependencies: A -> B, CH -> A, B -> E, BD -> C, EG -> H, DE -> F. Which of the following FDs is also guaranteed to be satisfied by R? a. CGH -> BF b. ACG -> DH c. ADG -> CH d. BCD -> FH

c

QN=27 (7971) Given the relation R(ABCDE) with the following FD's: D -> C, CE ->A, D ->A, and AE ->D Which of the following attribute set is a key? a. ABCDE b. CDE c. ABE d. BD

c

QN=3 (6797) A ____ is a powerful tool for creating and managing large amounts of data efficiently and allowing it to persist over long periods of time, safely a. Excel b. Database c. DBMS d. None of the others

c

QN=30 (7978) The relation R(ABCD) has following FDs: { A -> B ; B -> A ; A -> D ; D -> B } a. R is not in 2NF b. R is not in 3NF c. R is in 3NF d. None of the others

c

QN=33 (7975) Let R(A,B,C,D) with the following FDs: {AB->C, AC->B, AD->C} Choose a correct statement about R: a. R is in BCNF b. R is in 3NF c. R is in 2NF d. None of the others

c

QN=40 (7992) Normalization is a process of analyzing the given relation schema based on their Functional Dependencies (FDs) and primary keys to achieve the following: a. Minimizing redundancy b. Minimizing insertion anomalies c. All of the others d. Minimizing deletion and update anomalies

c

QN=14 (6818) Which of the followings is part of data model? a. Structure of the data b. Operations on the data c. Constraints on the data d. All of the others

d

QN=39 (8005) Which of the following statements is true? a. BCNF condition guarantees the non existence of the anomalies. b. In BCNF condition, the left side of every non trivial FD must be a super key. c. Any two-attribute relation is in BCNF. d. All of the others.

d

QN=44 (8007) Look at the following statements: (a)All relations in 3NF are also in 2NF (b)All relations in 2NF are also in 1NF (c)All relations in 1NF are also in BCNF (d)All relations in 1NF are also in 3NF a. (b) and (d) are true b. (a) and (c) are true c. (a) and (d) are true d. (a) and (b) are true

d

QN=46 (7997) Which of the following are guidelines for designing the relational schema ? a. Reduce the redundant values in tuples b. Reduce the NULL values in tuples c. Always make relations 3NF d. All of the others

d