4.dbi202

c

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=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

a

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

d

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

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=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=53 (9176) The SQL operations that are performed while a connection is active form a ____ a. Session b. Catalog c. Module d. None of the others

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

a

QN=40 (8534) A tuple which fails to participate in a join is called: a. dangling tuple b. child tuple c. parent tuple d. neighbor tuple

a

QN=41 (8538) (TRUE OR NULL) return: a. TRUE b. FALSE c. NULL d. None of the others

b

QN=42 (8552) Choose one correct statement: a. Two null values are equal b. Comparisons between two null values, or between a NULL and any other value, return unknown c. Comparisons between two null values, or between a NULL and any other value, return FALSE

a

QN=43 (8554) For what values of x, y, and z, including NULL, does the Boolean expression x <= 100 AND NOT(y >= 15 OR z = 35) have the truth value UNKNOWN? Identify one of those values from the list below. a. x = NULL, y = 0, z = 4. b. x = -2, y = -2, z = -2. c. x = 3, y = 0, z = 7. d. x = 2, y = -1, z = 6.

a

QN=44 (8551) Choose one correct statement: a. No two null values are equal b. Two null values are equal c. Comparisons between two null values, or between a NULL and any other value, return FALSE

d

QN=46 (8559) A database transaction, by definition, must be ACID (atomic, consistent, isolated and durable). What does "Isolated" mean? a. "Isolated" 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. "Isolated" means that: Transactions must not violate any integrity constraints during its execution c. "Isolated" means that: Transactions that have committed will survive permanently d. "Isolated" means that: how/when the changes made by one operation in one transaction become visible to other concurrent operations in other transactions

a

QN=47 (8578) What one is a wildcard used for pattern matching? a. "%" (for multi-character substitution) b. "?" (for single character substitution) c. "?" (for multi-character substitution)

b

QN=48 (8573) Suppose we have a relation instance R(A,B,C) as following: R A B C ---------------------------------- 1 2 3 4 5 6 7 8 9 Which is the result of the query: SELECT SUM(B) FROM R WHERE C > 10 a. 0 b. NULL c. 3 d. 10

e

QN=49 (8589) Choose the most correct statement about PRIMARY KEY: a. The PRIMARY KEY constraint uniquely identifies each record in a database table b. Primary keys must contain unique values c. A primary key column cannot contain NULL values d. Each table should have a primary key, and each table can have only ONE primary key e. All of the others

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)

a

QN=50 (8584) Foreign key constraints are created by using "_____" keyword to refer to the primary key of another table a. REFERENCES b. POINT TO c. REFER d. None of the others

b

QN=52 (8616) The most useful index on a relation is an index on its key. This is because: a. The index on non key attribute(s) runs slower b. The search operation based on the primary key is commonly used. c. The index on non key attribute(s) makes update operations to the relation more complex and time-consuming d. All of the others

a

QN=54 (9171) In PSM, the difference between a stored procedure and a function is that: a. A function has the return statement. b. We can declare local variables in a function. c. Loops are not allowed in a function. d. All of the others.

a

QN=55 (9182) The aim for the Object-relational database is to bridge the gap between conceptual data modelling techniques such as Entity-relationship diagram (ERD) and object-relational mapping (ORM), which often use classes and inheritance, and relational databases, which do not directly support them a. True b. False

d

QN=56 (9189) Choose the correct statement: a. A User-Defined Type (UDT) in SQL can be the type of a table b. A UDT can be the type of an attribute belonging to some table c. The form of UDT definition is: CREATE TYPE T AS (<primitive type | attribute declarations>) d. All of the others

a

QN=57 (9192) ______ is a set of markup declarations that define a document type for SGML-family markup languages (SGML, XML, HTML) a. Document Type Definition b. Document Definition Language c. Document Manipulation Language d. Document Control Language

b

QN=58 (9198) A ____ document defines the XML document structure with a list of legal elements and attributes a. XML b. DTD c. XSLT d. SGML

d

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

a

QN=60 (9207) A ____ is the framework under which data may exist and SQL operations on data may be executed a. SQL Environment b. SQL Statement c. SQL Parser d. SQL Optimizer

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

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