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SDP 6 (2)

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- at Quiz on SDP 6 (2), created by хомяк убийца on 17/12/2017.
хомяк убийца
Quiz by хомяк убийца, updated more than 1 year ago
хомяк убийца
Created by хомяк убийца over 6 years ago
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Resource summary

Question 1

Question
The ___________ R S keeps tuple in the first {left} relation R; if no matching tuple found in S, then the attribute of S in the join are filled with NULL values
Answer
  • o LEFT OUTER JOIN
  • o RIGHT OUTER JOIN
  • o FULL OUTER JOIN
  • o LEFT INNER JOIN

Question 2

Question
If a relation schema has more than one key, each is called a _______ key.
Answer
  • o Candidate
  • o Primary
  • o Public
  • o Foreign

Question 3

Question
A _________conflict arises when an attribute may have different domains in two schemas, e.g. pounds vs kilograms
Answer
  • o Domain
  • o Type
  • o Norming
  • o Constraints

Question 4

Question
UML _________ diagrams describe the dynamic relationships among components
Answer
  • o Behavioral
  • o Structural
  • o Class
  • o Direct

Question 5

Question
Objects in an object-oriented programming language exist only during program execution, therefore they are called transient objects; an object-oriented database can extend the existence of objects so that they are stored permanently, therefore they are called
Answer
  • o persistent object
  • o instance variable
  • o attribute
  • o object structure

Question 6

Question
_____ is the term used to refer to the problems that occur because of difference between the database model and the programming language model.
Answer
  • o Independence mismatch
  • o Denormalisation
  • o Redundancy
  • o Duplication

Question 7

Question
A __________________ is typically used to loop over the tuples in a query result
Answer
  • o Cursor {iterator variable}
  • o Shared variable
  • o Communication variables
  • o fetch

Question 8

Question
NULL values may mean value unknown, value exists but isn't available, and attribute does not apply to this tuple (value undefined)
Answer
  • True
  • False

Question 9

Question
A THETA JOIN uses any of the comparison operators =,<,> or (not equal)
Answer
  • True
  • False

Question 10

Question
For structured data, the schema information is mixed in with the data values, so it is sometimes referred to as self-describing data
Answer
  • True
  • False

Question 11

Question
The main advantage of using a function call interface is that it makes it easier to access multiple databases within the same application program
Answer
  • True
  • False

Question 12

Question
In PHP, Interpolating variables may occur within double-quoted or single-quoted strings
Answer
  • True
  • False

Question 13

Question
In PHP, the $d->query function takes an SQL command as its string argument and sends it to the database server for execution.
Answer
  • True
  • False

Question 14

Question
The ________________ property ensures that either all the database operations in a transaction are executed or none are
Answer
  • o Atomicity
  • o Transaction
  • o Isolation
  • o Concurrency

Question 15

Question
_______occurs when the same data is stored multiple times
Answer
  • o Redundancy
  • o Normalisation
  • o Denormalization
  • o Persistent

Question 16

Question
Creating a database design that only stores each logical data item in only one place is the database is called______
Answer
  • o Redundancy
  • o Normalization
  • o Denormalization
  • o Persistent

Question 17

Question
The ________________ property allows several users to update the same data in a controlled manner so that result of the updates is correct
Answer
  • o Atomicity
  • o Transaction
  • o Isolation
  • o Concurrency

Question 18

Question
An entity cannot exist in a database merely by being a member of a subclass, it must also be a member of the superclass
Answer
  • True
  • False

Question 19

Question
An entity that is a member of a subclass may inherit one, some, or all the attributes of the entity as a member of the superclass.
Answer
  • True
  • False

Question 20

Question
The theoretical basis of the relational data model is set theory and first-order predicate logic
Answer
  • True
  • False

Question 21

Question
Semantic integrity constraints may be enforced using mechanisms called triggers and assertions.
Answer
  • True
  • False

Question 22

Question
When mapping a binary M:N relationship type R, create a new relation S to represent R, including as foreign key attributes in S the primary keys of the relations that are the participating entity types (their combination in S is the composite primary key of S).
Answer
  • True
  • False

Question 23

Question
$_SESSION − An associative array containing session variables available to the current script
Answer
  • True
  • False

Question 24

Question
PHP makes use of mail() function to send an email. This function requires three mandatory arguments that specify the recipient's email address, the subject of the the message and the actual message additionally there are other two optional parameters
Answer
  • True
  • False

Question 25

Question
The interpreter identifies variable names within double-quoted strings by their initial character $ and replaces them with the value in the variable. This is known as interpolating variables within strings. Interpolation does not occur in single-quoted strings
Answer
  • True
  • False

Question 26

Question
SQLJ was developed after JDBC, which is used for accessing SQL data- bases from Java using function calls
Answer
  • True
  • False

Question 27

Question
Most NoSQL databases support automatic __________, meaning that you get high availability and disaster recovery
Answer
  • processing
  • scalability
  • replication
  • All of the mentioned

Question 28

Question
The Web Services Architecture supports interaction between a service provider, service requestor, and service registry
Answer
  • True
  • False

Question 29

Question
Multi-line PHP comments start with // and end with #.
Answer
  • True
  • False

Question 30

Question
Define types of abstractions by the relations as "A is made of/composed of B,C,D"
Answer
  • Classification
  • Aggregation
  • Generalization
  • Specialization

Question 31

Question
FETCH commands are issued in the program; each FETCH moves the cursor to the next row in the result of the query, making it the cur- rent row and copying its attribute values into the C (host language) program variables specified in the FETCH command by an INTO clause.</text>
Answer
  • True
  • False

Question 32

Question
Define types of abstractions by the relations as "B,C,D are special cases of A"
Answer
  • Classification
  • Aggregation
  • Generalization
  • Specialization

Question 33

Question
A JDBC driver is basically an implementation of the function calls specified in the JDBC application programming interface (API) for a particular vendor's RDBMS
Answer
  • True
  • False

Question 34

Question
In PHP, a numeric array associates a numeric index with each element in the array.
Answer
  • True
  • False

Question 35

Question
Before being able to process JDBC function calls with Java, it is necessary to import the JDBC class libraries, which are called java.sql.*.
Answer
  • True
  • False

Question 36

Question
How can you change "Hansen" into "Nilsen" in the "LastName" column in the Persons table?
Answer
  • UPDATE Persons SET LastName='Hansen' WHERE LastName='Nilsen'
  • UPDATE Persons SET LastName='Nilsen' WHERE LastName='Hansen'
  • MODIFY Persons SET LastName='Hansen' WHERE LastName='Nilsen'
  • UPDATE FROM Persons SET LastName='Nilsen' WHERE LastName='Hansen'

Question 37

Question
Publisher table contains id and name columns. Id is auto incremented and name is of varchar(40) type. Which of the following queries will execute NOT correctly?
Answer
  • INSERT INTO Publisher (name) values ('O'Reilly');
  • INSERT INTO Publisher (name) values ('O Reilly');
  • INSERT INTO Publisher (name) values ('OReilly');
  • INSERT INTO Publisher (name) values ('O-Reilly');

Question 38

Question
What is the correct order of clauses for a proper SQL query?
Answer
  • SELECT, FROM, WHERE, GROUP BY, HAVING, ORDER BY
  • SELECT, FROM, WHERE, GROUP BY, ORDER BY, HAVING
  • SELECT, FROM, GROUP BY, WHERE, HAVING, ORDER BY
  • SELECT, FROM, WHERE, HAVING, GROUP BY, ORDER BY
  • SELECT, FROM, ORDER BY, WHERE, GROUP BY, HAVING

Question 39

Question
Which clause indicates the table(s) from which data is to be retrieved?
Answer
  • FROM
  • SELECT
  • WHERE
  • GROUP BY
  • HAVING

Question 40

Question
Which clause is executed first in a SQL query?
Answer
  • • WHERE
  • • SELECT
  • • ON
  • • TOP
  • • FROM

Question 41

Question
Which of the following DROP statements is INCORRECT?
Answer
  • • DROP TABLE
  • • DROP DATABASE
  • • DROP ROW
  • • DROP INDEX

Question 42

Question
Which of the following is NOT a language element of SQL?
Answer
  • Expression
  • Data mining
  • Query
  • Statement
  • Clause

Question 43

Question
Which operator is used to search for a specified pattern in a column?
Answer
  • WHERE
  • LIKE
  • ALIASE
  • PATTERN

Question 44

Question
Which operator is used to select values within a range?
Answer
  • RANGE
  • AND
  • BETWEEN
  • OR

Question 45

Question
Which term is used to describe data organized in rows and columns?
Answer
  • Query
  • Program
  • Index
  • Table

Question 46

Question
With SQL, how can you delete the records where the "Address" is "Almaty" in the Student Table?
Answer
  • DROP ROW Student ='Almaty' FROM Address
  • DELETE FROM Student ROW Address ='Almaty'
  • DROP ROW Address ='Almaty' FROM Student
  • DELETE ROW Address ='Almaty' FROM Student

Question 47

Question
With SQL, how can you return all the records from a table named "Persons" sorted descending by "FirstName"?
Answer
  • SELECT * FROM Persons GROUP BY FirstName DESC
  • SELECT * FROM Persons WHERE FirstName DESC
  • SELECT * FROM Persons ORDER BY FirstName
  • SELECT * FROM Persons ORDER BY FirstName DESC

Question 48

Question
With SQL, how can you return the number of records in the "Employee" table?
Answer
  • SELECT COUNT(*) FROM Employee
  • SELECT * FROM Employee GROUP BY
  • SELECT NUM(*) FROM Employee
  • RETURN COUNT(*) FROM Employee

Question 49

Question
With SQL, how do you select all the records from a table named "Persons" where the value of the column "FirstName" starts with an "a"?
Answer
  • SELECT * FROM Persons WHERE FirstName LIKE 'a%';
  • SELECT * FROM Persons WHERE FirstName LIKE '%a%';
  • SELECT All FROM Persons WHERE FirstName LIKE='a';
  • SELECT * FROM Persons WHERE FirstName LIKE 'a*';

Question 50

Question
With SQL, how do you select all the records from a table named "Persons" where the "FirstName" is "Alma" and the "LastName" is "Alimova"?
Answer
  • SELECT * FROM Persons WHERE FirstName=' Alma ' AND LastName=' Alimova'
  • SELECT * FROM Persons WHERE FirstName=' Alma ' OR LastName=' Alimova'
  • SELECT FROM Persons WHERE FirstName=' Alma ' AND LastName=' Alimova'
  • SELECT * FROM Persons HAVING FirstName=' Alma ' AND LastName=' Alimova'

Question 51

Question
Which of the following is not a NoSQL database ?
Answer
  • SQL Server
  • MongoDB
  • Cassandra
  • None of the mentioned

Question 52

Question
Which of the following is a NoSQL Database Type ?
Answer
  • SQL
  • Document databases
  • JSON
  • All of the mentioned

Question 53

Question
Which of the following is a wide-column store ?
Answer
  • Cassandra
  • Riak
  • MongoDB
  • Redis

Question 54

Question
An ODMS provides a unique identity to each independent object stored in the database via a unique, system-generated ________
Answer
  • object identifier (OID)
  • literals
  • indirect pointer
  • constructor

Question 55

Question
Define types of abstractions by the relations as "A is a member of class B
Answer
  • Classification
  • Aggregation
  • Generalization
  • Specialization

Question 56

Question
Define types of abstractions by the relations as "B is-an A, C is-an A, D is-an A"
Answer
  • Classification
  • Aggregation
  • Generalization
  • Specialization

Question 57

Question
How will you close a MySql database using PHP?
Answer
  • mysql_destroy
  • mysql_exit
  • mysql_end
  • mysql_close

Question 58

Question
How will you concatenate two strings?
Answer
  • Using . operator
  • Using + operator
  • Using add() function
  • Using append() function

Question 59

Question
How will you connect a MySql database using PHP?
Answer
  • mysql_connection
  • mysql_query
  • mysql_fetch_array
  • mysql_connect

Question 60

Question
How will you destroy a session in PHP?
Answer
  • session_destroy()
  • destroy_session()
  • $_SESSION['destroy']
  • $_SESSION['']

Question 61

Question
How will you start a session in PHP?
Answer
  • session_start()
  • start_session()
  • $_SESSION['start']
  • $_SESSION['']

Question 62

Question
How will you unset a single session variable?
Answer
  • ![CDATA[<?phpunset($_SESSION['counter']);?>]]
  • ![CDATA[<?phpisset($_SESSION['counter']); ?>]]
  • $_SESSION['unset']
  • $_SESSION['']

Question 63

Question
Identify factors to consider in choosing one DBMS over another. I. Organization-wide adoption of a certain philosophy (data model, vendor, methodology, tools). II. Familiarity of personnel with the system. III. Availability of vendor services.
Answer
  • I,II
  • I,II,III
  • II,III
  • I,III

Question 64

Question
In which type of PHP arrays the element values can be strings or integers?
Answer
  • numeric
  • associative
  • indexed
  • none

Question 65

Question
In XML schema, the tag ________________ is used to specify foreign keys
Answer
  • xsd:keyref
  • xsd:element
  • xsd: unique
  • xsd:foreignkey

Question 66

Question
NoSQL databases is used mainly for handling large volumes of ______________ data
Answer
  • unstructured
  • structured
  • semi-structured
  • all of the mentioned

Question 67

Question
Point out the wrong statement
Answer
  • Non Relational databases require that schemas be defined before you can add data
  • NoSQL databases are built to allow the insertion of data without a predefined schema
  • NewSQL databases are built to allow the insertion of data without a predefined schema
  • All of the mentioned

Question 68

Question
The ___ notation applies to user-defined subclasses of a specialization that must be ________, as illustrated by the specialization "every STUDENT must be either an GRADUATE_STUDENT, or a UNDERGRADUATE_STUDENT"
Answer
  • d, disjoint
  • j, joint
  • o, overlapping
  • u, union

Question 69

Question
The case of specialization what the same (real-world) entity may be a member of more than one subclass of the specialization for example, an alumnus may also be an employee and may also be a student pursuing an advanced degree (PERSON entity type, which is specialized into the subclasses {EMPLOYEE, ALUMNUS, STUDENT})
Answer
  • disjoint
  • joint
  • overlapping
  • union

Question 70

Question
This auto-global built-in array variable which provides the IP (Internet Protocol) address of the client user computer that is accessing the server, for example 129.107.61.8.
Answer
  • $_SERVER['SERVER_NAME']
  • $_SERVER['REMOTE_ADDRESS']
  • $_SERVER['REMOTE_HOST']
  • $_SERVER['PATH_INFO']
  • $_SERVER['QUERY_STRING']

Question 71

Question
This auto-global built-in array variable which provides the part of the URL address that comes after a backslash (/) at the end of the URL.
Answer
  • $_SERVER['SERVER_NAME']
  • $_SERVER['REMOTE_ADDRESS']
  • $_SERVER['REMOTE_HOST']
  • $_SERVER['PATH_INFO']
  • $_SERVER['QUERY_STRING']

Question 72

Question
This auto-global built-in array variable which provides the string that holds parameters in a URL after a question mark (?) at the end of the URL. This can hold search parameters, for example
Answer
  • $_SERVER['SERVER_NAME']
  • $_SERVER['REMOTE_ADDRESS']
  • $_SERVER['REMOTE_HOST']
  • $_SERVER['PATH_INFO']
  • $_SERVER['QUERY_STRING']

Question 73

Question
This auto-global built-in array variablewhich provides the Web site name of the server computer where the PHP interpreter is running.
Answer
  • $_SERVER['SERVER_NAME']
  • $_SERVER['REMOTE_ADDRESS']
  • $_SERVER['REMOTE_HOST']
  • $_SERVER['PATH_INFO']
  • $_SERVER['QUERY_STRING']

Question 74

Question
What does PHP stands for
Answer
  • Personal Hypertext Processor
  • PHP: Hypertext Preprocessor
  • Private Home Page
  • Private Hypertext Preprocessor

Question 75

Question
What does S in BASE refers to?
Answer
  • System Consistence
  • System Availability
  • Changing System
  • System Stability

Question 76

Question
[What does the term "I" expands to in the term "ACID"?
Answer
  • Isolated
  • Inseparable
  • Indispensable
  • Insulted

Question 77

Question
What does XML stand for?
Answer
  • eXtensible Markup Language
  • Example Markup Language
  • X-Markup Language
  • eXtra Modern Link

Question 78

Question
What does XSL stand for?
Answer
  • eXtensible Stylesheet Language
  • eXtra Style Language
  • eXpandable Style Language
  • eXtensible Style Listing

Question 79

Question
What is the correct syntax of the declaration which defines the XML version?
Answer
  • <?xml version="1.0" />
  • <?xml version="1.0"?>
  • <xml version="1.0" />

Question 80

Question
Which company did Cassandra was primarily developed in?
Answer
  • Apache
  • Facebook
  • Google
  • Amazon

Question 81

Question
Which feature of CAP refers to load balancing
Answer
  • None of these
  • С
  • А
  • Р

Question 82

Question
Which of the following are the simplest NoSQL databases
Answer
  • Key-value
  • Wide-column
  • Document
  • All of the mentioned

Question 83

Question
Which of the following is correct about PHP
Answer
  • PHP is a recursive acronym for "PHP: Hypertext Preprocessor".]
  • PHP is a server side scripting language that is embedded in HTML
  • It is used to manage dynamic content, databases, session tracking, even build entire e-commerce sites
  • All of these statement

Question 84

Question
Which of the following is correct about variable naming rules?
Answer
  • Variable names must begin with a letter or underscore character.
  • A variable name can consist of numbers, letters, underscores.
  • you cannot use characters like + , - , % , ( , ) . &amp; , etc in a variable name.
  • All of these statement

Question 85

Question
Which of the following is not a NoSQL database?
Answer
  • SQL Server
  • MongoDB
  • Cassandra
  • None of the mentioned

Question 86

Question
Which of the following method can be used to create a MySql database using PHP?
Answer
  • mysql_connect()
  • mysql_query()
  • mysql_close()
  • None of the above

Question 87

Question
Which of them could not be applied to techniques for looping through arrays in PHP
Answer
  • $courses = ('Database', 'OS', 'Graphics', 'Data Mining');
  • $courses = array('Database', 'OS', 'Graphics', 'Data Mining');
  • $teaching = array('Database' => 'Smith', 'OS' => 'Carrick', 'Graphics' => 'Kam');
  • $teaching['Graphics'] = 'Benson';
  • $alt_row_color = array('blue', 'yellow');

Question 88

Question
A key difference between structured and semistructured data concerns how the schema constructs (such as the names of attributes, relationships, and entity types) are handled.
Answer
  • True
  • False

Question 89

Question
A large database typically has large transaction volumes and rates, is used in service sector industries, and runs 24/7
Answer
  • True
  • False

Question 90

Question
A library of functions, also known as an application programming interface (API), is used to access the database
Answer
  • True
  • False

Question 91

Question
A safer way to do inserts and other queries is through the use of placeholders (specified by the ? symbol) in PHP
Answer
  • True
  • False

Question 92

Question
Associative array − An array with strings as index. This stores element values in association with key values rather than in a strict linear index order.
Answer
  • True
  • False

Question 93

Question
In SQLJ, an iterator is a type of object associated with a collection (set or multiset) of records in a query result.
Answer
  • True
  • False

Question 94

Question
In SQLJ, embedded SQL commands are preceded by #sql.
Answer
  • True
  • False

Question 95

Question
In XML schema, it is possible to specify constraints that correspond to unique and primary key constraints in a relational database, as well as foreign keys constraints.
Answer
  • True
  • False

Question 96

Question
Interfaces are defined to provide a common function names to the implementers. Different implementers can implement those interfaces according to their requirements. You can say, interfaces are skeletons which are implemented by developers.
Answer
  • True
  • False

Question 97

Question
Numeric array − An array with a numeric index. Values are stored and accessed in linear fashion.
Answer
  • True
  • False

Question 98

Question
OPEN CURSOR command is issued to indicate that we are done with processing the result of the query associated with that cursor.
Answer
  • True
  • False

Question 99

Question
PHP is written in C and usually comes installed with Unix; for other operating systems, the PHP interpreter can be downloaded from http://www.php.net.
Answer
  • True
  • False

Question 100

Question
The cursor is declared when the SQL query command is declared in the program. Later in the program, an OPEN CURSOR command fetches the query result from the database and sets the cursor to a position before the first row in the result of the query
Answer
  • True
  • False

Question 101

Question
The typical mechanisms for making an object persistent are naming and reachability
Answer
  • True
  • False

Question 102

Question
XML attribute values must always be enclosed in quotes
Answer
  • True
  • False

Question 103

Question
XML elements cannot be empty
Answer
  • True
  • False

Question 104

Question
XML's goal is to replace HTML
Answer
  • True
  • False

Question 105

Question
XQuery is the language for querying XML data
Answer
  • True
  • False

Question 106

Question
The case represents a single superclass/subclass relationship with more than one superclass, where the superclasses represent different entity types
Answer
  • disjoint
  • joint
  • overlapping
  • union

Question 107

Question
When a database design is in ____________, each value in a tuple is in atomic value.
Answer
  • First normal form
  • Second normal form
  • Third normal form
  • Forth normal form

Question 108

Question
Redundancy leads to three potential problems. Briefly describe each of the three.
Answer
  • Duplication of effort
  • Storage space is wasted
  • Multiple occurrences of data may become inconsistent

Question 109

Question
What two things does minimizing redundancy imply
Answer
  • Minimizing redundant storage of the same information.
  • Reducing the need for multiple updates to maintain consistency across multiple copies of the same information.

Question 110

Question
What are the four informal guidelines that may be used to measure the quality of a relation schema design?
Answer
  • Making sure the semantics of the attributes is clear in the schema.
  • Reducing the redundant information in tuples.
  • Reducing the NULL values in tuples.
  • Disallowing the possibility of generating spurious tuples.

Question 111

Question
What are the three goals of database design?
Answer
  • Satisfy the information content requirements of the specified users and applications.
  • Provide a natural and easy-to-understand structuring of the information.
  • Support processing requirements and any performance objectives

Question 112

Question
Identify two of the three factors to consider in choosing one DBMS over another
Answer
  • Organization-wide adoption of a certain philosophy (data model, vendor, methodology, tools).
  • Familiarity of personnel with the system
  • Availability of vendor services

Question 113

Question
Identify the three criteria to guide the choice of physical database design options
Answer
  • Response time.
  • Space utilization
  • Transaction throughput.

Question 114

Question
A join operation joins _____ tables into _____.
Answer
  • three, two
  • three, one
  • four, two
  • two, one

Question 115

Question
A primary key should be defined as: I. NULL II. NOT NULL III. Optional
Answer
  • I, II
  • I, III
  • II only
  • I, II, III

Question 116

Question
A subquery in an SQL SELECT statement is enclosed in:
Answer
  • braces -- {...}.
  • CAPITAL LETTERS
  • parenthesis -- (...)
  • brackets -- [...].

Question 117

Question
SQL query and modification commands make up a(n) ________ .
Answer
  • DML
  • DDL
  • HTML
  • XML

Question 118

Question
The command to eliminate a table from a database is:
Answer
  • • REMOVE TABLE TableName
  • • DROP TABLE TableName
  • • DELETE TABLE TableName
  • • UPDATE TABLE TableName

Question 119

Question
________ stores are used to store information about networks, such as social connections.
Answer
  • • Key-value
  • • Wide-column
  • • Graph

Question 120

Question
A ___________ is an indirect functional dependency, one in which X->Z only by virtue of X->Y and Y->Z
Answer
  • • Multivalued Dependencies
  • • Join Dependency
  • • Trivial Functional Dependency
  • • Transitive Dependencies

Question 121

Question
A table is in 3NF if it is in 2NF and if it has no ____________
Answer
  • • Functional Dependencies
  • • Transitive Dependencies
  • • Trivial Functional Dependency
  • • Multivalued Dependencies

Question 122

Question
A table is in BCNF if it is in 3NF and if every determinant is a ___________ key.
Answer
  • • Dependent
  • • Normal
  • • Candidate
  • Both Normal and Candidate

Question 123

Question
Anomalies are avoided by splitting the offending relation into multiple relations, is also known as
Answer
  • • Accupressure
  • • Decomposition
  • • Both Decomposition and Precomposition
  • • Precomposition

Question 124

Question
Every time attribute A appears, it is matched with the same value of attribute B, but not the same value of attribute C. Therefore, it is true that:
Answer
  • A-->B
  • A-->C
  • A-->(B,C)
  • (B,C)-->A

Question 125

Question
For select operation the ________ appear in the subscript and the ___________ argument appears in the parenthesis after the sigma.
Answer
  • • Predicates, relation
  • • Relation, Predicates
  • • Operation, Predicates
  • • Relation, Operation

Question 126

Question
If X -> Y, which of the following would make Y fully dependent on X?
Answer
  • • X consists of multiple attributes
  • • Y is a single attribute
  • • Y consists of multiple attributes
  • • X is a single attribute

Question 127

Question
In a given relationship R, if an attribute A uniquely defines all other attributes, then the attribute A is a key attribute which is also known as the _________ key.
Answer
  • • Candidate
  • • Join
  • • Functional
  • • None of the Mentioned

Question 128

Question
In EER modeling, specialization is the process of generating
Answer
  • • entities out of attributes
  • • attributes out of entities
  • • subclasses out of superclasses
  • • superclasses out of subclasses

Question 129

Question
In precedence of set operators the expression is evaluated from
Answer
  • • Left to left
  • • Left to right
  • • Right to left
  • • From user specification

Question 130

Question
The ___________ operation, denoted by −, allows us to find tuples that are in one relation but are not in another.
Answer
  • • Union
  • • Set-difference
  • • Difference
  • • Intersection

Question 131

Question
The functional dependency X -> Y is true if
Answer
  • a value of X uniquely determines a value of Y
  • the value of Y depends on the collective values of X
  • the value of X depends on the collective values of Y
  • a value of Y uniquely determines a value of X

Question 132

Question
The result of a set difference operation r - s will be
Answer
  • those tuples that are in s but not in r
  • those tuples that are in r but not in s
  • tuples in s after deducting their values by the corresponding values in the tuples in r
  • tuples in r after deducting their values by the corresponding values in the tuples in s

Question 133

Question
What does a projection operation do?
Answer
  • It extends the number of rows in a table.
  • It extends the number of columns in a table
  • It selects columns from a table
  • It selects rows from a table.

Question 134

Question
When the values in one or more attributes being used as a foreign key must exist in another set of one or more attributes in another table, we have created a(n)
Answer
  • Transitive Dependency
  • Insertion Anomaly
  • Referential Integrity Constraint
  • Normal Form

Question 135

Question
Which is a join condition contains an equality operator
Answer
  • Equijoins
  • Cartesian
  • Natural
  • Left

Question 136

Question
Which is a unary operation
Answer
  • Selection operation
  • Primitive operation
  • Projection operation
  • Generalized selection

Question 137

Question
Which of the following is a fundamental operation in relational algebra
Answer
  • Set intersection
  • Natural join
  • Assignment
  • None of the mentioned

Question 138

Question
Which of the following is not a restriction for a table to be a relation?
Answer
  • The cells of the table must contain a single value
  • The columns must be ordered
  • No two rows in a table may be identical

Question 139

Question
Which of the following is used to denote the selection operation in relational algebra?
Answer
  • Pi
  • Sigma
  • Lambda
  • Omega

Question 140

Question
Y is transitively dependent on X, if
Answer
  • X -> A, B and Y -> A, B
  • X -> Y and A -> Y
  • X -> A, B and A -> Y
  • X -> Y and Y -> A

Question 141

Question
For two tables to be union compatible, corresponding columns from each table should have which of the following?
Answer
  • the same domain
  • the same name
  • different domains
  • different names
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