QN=12 (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)?

d. R is in Boyce Codd Normal Form

QN=14 (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

QN=15 (7999) What is the difference between the 2NF and the 3NF?

a. 2NF deals with partial functional dependency, while 3NF deals with transitive functional dependency

b. 2NF deals with transitive functional dependency, while 3NF deals with partial functional dependency

QN=16 (7993) What is "de-normalization"?

a. De-normalization means allowing redundancy in a table

b. De-normalization means allowing duplicate columns appeared in a table

c. De-normalization means allowing a table to have more than 3 columns

d. De-normalization means allowing a table to have more than 1024 columns

QN=17 (8004) What is the benefit of "de-normalization"?

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)

a. "de-normalization" has no benefit

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

QN=18 (8022) The key for a weak entity set E is .........

d. Zero or more attributes of E and key attributes from supporting entity sets

a. Zero or more attributes of E

b. The set of attributes of supporting relationships for E

c. The set of attributes of supporting entity sets

QN=21 (8032) An association class in UML is similar to ______ in the ER model

a. attributes on a relationship

QN=22 (8009) In UML, what is the difference between an aggregation and a composition?

a. In composition, when the owning object is destroyed, so are the contained objects. In aggregation, this is not necessarily true.

b. In aggregation, when the owning object is destroyed, so are the contained objects. In composition, this is not necessarily true.

d. There is no difference between an aggregation and a composition

QN=25 (8236) Choose the correct statement:

a. Aggregate functions perform a calculation on a set of values and return a single value

b. Aggregate functions perform a calculation on a single value and return a single value

c. Aggregate functions perform a calculation on a set of values and return a relation

d. Aggregate functions perform a calculation on a set of values and return a row

QN=30 (8517) How we can understand about this statement: "All aggregate functions are deterministic"?

a. This means aggregate functions return the same value any time they are called by using a specific set of input values

b. This means aggregate functions return the different values each time they are called by using a specific set of input values

c. This means aggregate functions return the same value any time they are called by using any set of input values

QN=31 (8523) When we apply set operators (UNION, INTERSECT, EXCEPT) to two relations R and S, which conditions on R and S must be satisfied?

a. R and S must have schemas with identical sets of attributes and the types (domains) for each attributes must be the same in R and S

b. Before we compute the set-theoretic union, intersection, or difference of sets of tuples, the columns of R and S must be ordered so that the order of attributes is the same for both relations

QN=36 (8542) What does NULL mean?

a. The value NULL means UNKNOWN

b. The value NULL means '' (empty string)

c. The value NULL means ' ' (space character)

QN=39 (8558) Three properties of a lock in DBMS are: a)Granularity: the size of the lock b) Granularity: the type of the lock c) Mode: the type of the lock d) Duration: the time in seconds that the DBMS waits for a lock to be released

a. (a) and (c) and (d) are true

b. (a) and (b) and (d) are true

c. (b) and (c) and (d) are true

d. (a) and (b) and (c) are true

QN=40 (8560) A database transaction, by definition, must be ACID (atomic, consistent, isolated and durable). What does "Durable" mean?

c. "Durable" means that: Transactions that have committed will survive permanently

a. "Durable" means that: Transactions provide an "all-or-nothing" proposition, stating that each work-unit performed in a database must either complete in its entirety or have no effect whatsoever

b. "Durable" means that: Transactions must not violate any integrity constraints during its execution

QN=41 (8569) Suppose relation R(A,B). Choose the SQL statement that is equivalent to the following RA expression: [ file:8569.jpg ]

b. SELECT (A+B) AS C FROM R WHERE (A+B) > 10

QN=42 (8575) What is the difference between the WHERE and HAVING SQL clauses?

c. The WHERE SQL clause condition(s) is applied to all rows in the result set before the HAVING clause is applied (if present). The HAVING clause is used only with SELECT SQL statements and specifies a search condition for an aggregate or a group

a. The WHERE and the HAVING clauses are identical

b. The HAVING SQL clause condition(s) is applied to all rows in the result set before the WHERE clause is applied (if present). The WHERE clause is used only with SELECT SQL statements and specifies a search condition for an aggregate or a group

QN=43 (8599) Choose the correct statement.

a. You can remove a trigger by dropping it or by dropping the trigger table

b. The syntax to remove a trigger is: DROP TRIGGER <trigger_name>

c. Use ALTER TRIGGER to change the definition of a trigger

QN=44 (8585) Suppose R and S are 2 relations. R is the parent of S. And the relationship between R and S is set to "ON DELETE CASCADE". This means that:

b. We can delete a row from R although that row has children in S (and in this case, all the children will be deleted too)

a. We can delete a row from R if that row has children in S (and in this case, the database server will raise up an error)

QN=45 (8592) To create a DEFAULT constraint on the "City" column of the table PERSON which is already created, use the following SQL:

a. ALTER TABLE Person ALTER COLUMN City SET DEFAULT 'SANDNES'

b. ALTER TABLE Person EDIT COLUMN City SET DEFAULT 'SANDNES'

c. ALTER TABLE Person UPDATE COLUMN City SET DEFAULT 'SANDNES'

d. ALTER TABLE Person MODIFY COLUMN City SET DEFAULT 'SANDNES'

QN=46 (8582) Three basic types of database integrity constraints are: (a)Entity integrity (b) Domain integrity (c) Referential integrity (d) Primary key integrity

a. (a) and (b) and (c) are true

b. (a) and (b) and (d) are true

c. (a) and (c) and (d) are true

d. (b) and (c) and (d) are true

QN=48 (8600) What is difference between PRIMARY KEY and UNIQUE KEY ?

a. A table can have more than one UNIQUE KEY constraint but only one PRIMARY KEY

b. A table can have more than one PRIMARY KEY constraint but only one UNIQUE KEY

c. UNIQUE KEY and PRIMARY KEY are the same

QN=50 (8620) Select the most correct answer

a. An index is a data structure used to speed access to tuples of a relation, given values of one or more attributes

b. The key for index can be any attribute or set of attributes, and need not be the key of the relation

c. We can think of the index as a binary search tree of (key, locations) pairs in which a key a is associated with a set of locations of the tuples

DBI202_PART1

Authored by Phạm Ngân

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120 questions

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MULTIPLE CHOICE QUESTION

30 sec • 1 pt

QN=1 (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

b. Database Instance

c. Schema

d. Schema Instance

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

QN=2 (6801) Choose the most correct statement.

a. Database is created and maintained by a DMBS

b. All of the others

c. Database is a collection of data that is managed by a DBMS

d. Database is a collection of information that exists over a long period of time

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

QN=3 (6802) Which of following is never used as a data model?

a. Hierarchical data model

b. None of the others

c. Graph-based data model

d. Tree-based data model

e. Relational data model

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

QN=4 (6817) A ____ is a relation name, together with the attributes of that relation.

a. schema

b. database

c. database instance

d. schema instance

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

QN=5 (6824) A ___ is a notation for describing the structure of the data in a database, along with the constraints on that data

a. data model

b. database management system

c. data operation

d. data manipulation

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

QN=6 (6827) A _____ is a language for defining data structures

a. DDL

b. DML

c. DCL

d. None of the others

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

QN=7 (6834) Which statement is used to remove a relation named R?

a. DROP TABLE R;

b. REMOVE TABLE R;

c. DELETE TABLE R;

d. TRUNCATE TABLE R;

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DBI202_PART1

QN=1 (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

QN=2 (6801) Choose the most correct statement.

QN=3 (6802) Which of following is never used as a data model?

QN=4 (6817) A ____ is a relation name, together with the attributes of that relation.

QN=5 (6824) A ___ is a notation for describing the structure of the data in a database, along with the constraints on that data

QN=6 (6827) A _____ is a language for defining data structures

QN=7 (6834) Which statement is used to remove a relation named R?

QN=8 (6829) What is another term for a row in a relational table?

QN=9 (7961) Given a relation R(A,B,C,D). Which of the followings is trivial?

QN=10 (7972) Let R(ABCD) be a relation with functional dependencies
{A -> B,
C -> B,
B -> D}
What is the key for R (choose one)

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Similar Resources on Wayground

Popular Resources on Wayground

DBI202_PART1

QN=1 (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

QN=2 (6801) Choose the most correct statement.

QN=3 (6802) Which of following is never used as a data model?

QN=4 (6817) A ____ is a relation name, together with the attributes of that relation.

QN=5 (6824) A ___ is a notation for describing the structure of the data in a database, along with the constraints on that data

QN=6 (6827) A _____ is a language for defining data structures

QN=7 (6834) Which statement is used to remove a relation named R?

QN=8 (6829) What is another term for a row in a relational table?

QN=9 (7961) Given a relation R(A,B,C,D). Which of the followings is trivial?

QN=10 (7972) Let R(ABCD) be a relation with functional dependencies{A -> B,C -> B,B -> D}What is the key for R (choose one)

Access all questions and much more by creating a free account

Similar Resources on Wayground

Popular Resources on Wayground

QN=10 (7972) Let R(ABCD) be a relation with functional dependencies
{A -> B,
C -> B,
B -> D}
What is the key for R (choose one)