11779594
Descripción
Test por хомяк убийца, actualizado hace más de 1 año
|
Creado por хомяк убийца
hace más de 6 años
|
|
Pregunta 1
Pregunta
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
Respuesta
-
o LEFT OUTER JOIN
-
o RIGHT OUTER JOIN
-
o FULL OUTER JOIN
-
o LEFT INNER JOIN
Pregunta 2
Pregunta
If a relation schema has more than one key, each is called a _______ key.
Respuesta
-
o Candidate
-
o Primary
-
o Public
-
o Foreign
Pregunta 3
Pregunta
A _________conflict arises when an attribute may have different domains in two schemas, e.g. pounds vs kilograms
Respuesta
-
o Domain
-
o Type
-
o Norming
-
o Constraints
Pregunta 4
Pregunta
UML _________ diagrams describe the dynamic relationships among components
Respuesta
-
o Behavioral
-
o Structural
-
o Class
-
o Direct
Pregunta 5
Pregunta
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
Respuesta
-
o persistent object
-
o instance variable
-
o attribute
-
o object structure
Pregunta 6
Pregunta
_____ is the term used to refer to the problems that occur because of difference between the database model and the programming language model.
Respuesta
-
o Independence mismatch
-
o Denormalisation
-
o Redundancy
-
o Duplication
Pregunta 7
Pregunta
A __________________ is typically used to loop over the tuples in a query result
Respuesta
-
o Cursor {iterator variable}
-
o Shared variable
-
o Communication variables
-
o fetch
Pregunta 8
Pregunta
NULL values may mean value unknown, value exists but isn't available, and attribute does not apply to this tuple (value undefined)
Respuesta
- True
- False
Pregunta 9
Pregunta
A THETA JOIN uses any of the comparison operators =,<,> or (not equal)
Respuesta
- True
- False
Pregunta 10
Pregunta
For structured data, the schema information is mixed in with the data values, so it is sometimes referred to as self-describing data
Respuesta
- True
- False
Pregunta 11
Pregunta
The main advantage of using a function call interface is that it makes it easier to access multiple databases within the same application program
Respuesta
- True
- False
Pregunta 12
Pregunta
In PHP, Interpolating variables may occur within double-quoted or single-quoted strings
Respuesta
- True
- False
Pregunta 13
Pregunta
In PHP, the $d->query function takes an SQL command as its string argument and sends it to the database server for execution.
Respuesta
- True
- False
Pregunta 14
Pregunta
The ________________ property ensures that either all the database operations in a transaction are executed or none are
Respuesta
-
o Atomicity
-
o Transaction
-
o Isolation
-
o Concurrency
Pregunta 15
Pregunta
_______occurs when the same data is stored multiple times
Respuesta
-
o Redundancy
-
o Normalisation
-
o Denormalization
-
o Persistent
Pregunta 16
Pregunta
Creating a database design that only stores each logical data item in only one place is the database is called______
Respuesta
-
o Redundancy
-
o Normalization
-
o Denormalization
-
o Persistent
Pregunta 17
Pregunta
The ________________ property allows several users to update the same data in a controlled manner so that result of the updates is correct
Respuesta
-
o Atomicity
-
o Transaction
-
o Isolation
-
o Concurrency
Pregunta 18
Pregunta
An entity cannot exist in a database merely by being a member of a subclass, it must also be a member of the superclass
Respuesta
- True
- False
Pregunta 19
Pregunta
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.
Respuesta
- True
- False
Pregunta 20
Pregunta
The theoretical basis of the relational data model is set theory and first-order predicate logic
Respuesta
- True
- False
Pregunta 21
Pregunta
Semantic integrity constraints may be enforced using mechanisms called triggers and assertions.
Respuesta
- True
- False
Pregunta 22
Pregunta
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).
Respuesta
- True
- False
Pregunta 23
Pregunta
$_SESSION − An associative array containing session variables available to the current script
Respuesta
- True
- False
Pregunta 24
Pregunta
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
Respuesta
- True
- False
Pregunta 25
Pregunta
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
Respuesta
- True
- False
Pregunta 26
Pregunta
SQLJ was developed after JDBC, which is used for accessing SQL data- bases from Java using function calls
Respuesta
- True
- False
Pregunta 27
Pregunta
Most NoSQL databases support automatic __________, meaning that you get high availability and disaster recovery
Respuesta
-
processing
-
scalability
-
replication
-
All of the mentioned
Pregunta 28
Pregunta
The Web Services Architecture supports interaction between a service provider, service requestor, and service registry
Respuesta
- True
- False
Pregunta 29
Pregunta
Multi-line PHP comments start with // and end with #.
Respuesta
- True
- False
Pregunta 30
Pregunta
Define types of abstractions by the relations as "A is made of/composed of B,C,D"
Respuesta
-
Classification
-
Aggregation
-
Generalization
-
Specialization
Pregunta 31
Pregunta
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>
Respuesta
- True
- False
Pregunta 32
Pregunta
Define types of abstractions by the relations as "B,C,D are special cases of A"
Respuesta
-
Classification
-
Aggregation
-
Generalization
-
Specialization
Pregunta 33
Pregunta
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
Respuesta
- True
- False
Pregunta 34
Pregunta
In PHP, a numeric array associates a numeric index with each element in the array.
Respuesta
- True
- False
Pregunta 35
Pregunta
Before being able to process JDBC function calls with Java, it is necessary to import the JDBC class libraries, which are called java.sql.*.
Respuesta
- True
- False
Pregunta 36
Pregunta
How can you change "Hansen" into "Nilsen" in the "LastName" column in the Persons table?
Respuesta
-
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'
Pregunta 37
Pregunta
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?
Respuesta
-
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');
Pregunta 38
Pregunta
What is the correct order of clauses for a proper SQL query?
Respuesta
-
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
Pregunta 39
Pregunta
Which clause indicates the table(s) from which data is to be retrieved?
Respuesta
-
FROM
-
SELECT
-
WHERE
-
GROUP BY
-
HAVING
Pregunta 40
Pregunta
Which clause is executed first in a SQL query?
Respuesta
-
• WHERE
-
• SELECT
-
• ON
-
• TOP
-
• FROM
Pregunta 41
Pregunta
Which of the following DROP statements is INCORRECT?
Respuesta
-
• DROP TABLE
-
• DROP DATABASE
-
• DROP ROW
-
• DROP INDEX
Pregunta 42
Pregunta
Which of the following is NOT a language element of SQL?
Respuesta
-
Expression
-
Data mining
-
Query
-
Statement
-
Clause
Pregunta 43
Pregunta
Which operator is used to search for a specified pattern in a column?
Respuesta
-
WHERE
-
LIKE
-
ALIASE
-
PATTERN
Pregunta 44
Pregunta
Which operator is used to select values within a range?
Respuesta
-
RANGE
-
AND
-
BETWEEN
-
OR
Pregunta 45
Pregunta
Which term is used to describe data organized in rows and columns?
Respuesta
-
Query
-
Program
-
Index
-
Table
Pregunta 46
Pregunta
With SQL, how can you delete the records where the "Address" is "Almaty" in the Student Table?
Respuesta
-
DROP ROW Student ='Almaty' FROM Address
-
DELETE FROM Student ROW Address ='Almaty'
-
DROP ROW Address ='Almaty' FROM Student
-
DELETE ROW Address ='Almaty' FROM Student
Pregunta 47
Pregunta
With SQL, how can you return all the records from a table named "Persons" sorted descending by "FirstName"?
Respuesta
-
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
Pregunta 48
Pregunta
With SQL, how can you return the number of records in the "Employee" table?
Respuesta
-
SELECT COUNT(*) FROM Employee
-
SELECT * FROM Employee GROUP BY
-
SELECT NUM(*) FROM Employee
-
RETURN COUNT(*) FROM Employee
Pregunta 49
Pregunta
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"?
Respuesta
-
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*';
Pregunta 50
Pregunta
With SQL, how do you select all the records from a table named "Persons" where the "FirstName" is "Alma" and the "LastName" is "Alimova"?
Respuesta
-
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'
Pregunta 51
Pregunta
Which of the following is not a NoSQL database ?
Respuesta
-
SQL Server
-
MongoDB
-
Cassandra
-
None of the mentioned
Pregunta 52
Pregunta
Which of the following is a NoSQL Database Type ?
Respuesta
-
SQL
-
Document databases
-
JSON
-
All of the mentioned
Pregunta 53
Pregunta
Which of the following is a wide-column store ?
Respuesta
-
Cassandra
-
Riak
-
MongoDB
-
Redis
Pregunta 54
Pregunta
An ODMS provides a unique identity to each independent object stored in the database via a unique, system-generated ________
Respuesta
-
object identifier (OID)
-
literals
-
indirect pointer
-
constructor
Pregunta 55
Pregunta
Define types of abstractions by the relations as "A is a member of class B
Respuesta
-
Classification
-
Aggregation
-
Generalization
-
Specialization
Pregunta 56
Pregunta
Define types of abstractions by the relations as "B is-an A, C is-an A, D is-an A"
Respuesta
-
Classification
-
Aggregation
-
Generalization
-
Specialization
Pregunta 57
Pregunta
How will you close a MySql database using PHP?
Respuesta
-
mysql_destroy
-
mysql_exit
-
mysql_end
-
mysql_close
Pregunta 58
Pregunta
How will you concatenate two strings?
Respuesta
-
Using . operator
-
Using + operator
-
Using add() function
-
Using append() function
Pregunta 59
Pregunta
How will you connect a MySql database using PHP?
Respuesta
-
mysql_connection
-
mysql_query
-
mysql_fetch_array
-
mysql_connect
Pregunta 60
Pregunta
How will you destroy a session in PHP?
Respuesta
-
session_destroy()
-
destroy_session()
-
$_SESSION['destroy']
-
$_SESSION['']
Pregunta 61
Pregunta
How will you start a session in PHP?
Respuesta
-
session_start()
-
start_session()
-
$_SESSION['start']
-
$_SESSION['']
Pregunta 62
Pregunta
How will you unset a single session variable?
Respuesta
-
![CDATA[<?phpunset($_SESSION['counter']);?>]]
-
![CDATA[<?phpisset($_SESSION['counter']); ?>]]
-
$_SESSION['unset']
-
$_SESSION['']
Pregunta 63
Pregunta
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.
Respuesta
-
I,II
-
I,II,III
-
II,III
-
I,III
Pregunta 64
Pregunta
In which type of PHP arrays the element values can be strings or integers?
Respuesta
-
numeric
-
associative
-
indexed
-
none
Pregunta 65
Pregunta
In XML schema, the tag ________________ is used to specify foreign keys
Respuesta
-
xsd:keyref
-
xsd:element
-
xsd: unique
-
xsd:foreignkey
Pregunta 66
Pregunta
NoSQL databases is used mainly for handling large volumes of ______________ data
Respuesta
-
unstructured
-
structured
-
semi-structured
-
all of the mentioned
Pregunta 67
Pregunta
Point out the wrong statement
Respuesta
-
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
Pregunta 68
Pregunta
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"
Respuesta
-
d, disjoint
-
j, joint
-
o, overlapping
-
u, union
Pregunta 69
Pregunta
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})
Respuesta
-
disjoint
-
joint
-
overlapping
-
union
Pregunta 70
Pregunta
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.
Respuesta
-
$_SERVER['SERVER_NAME']
-
$_SERVER['REMOTE_ADDRESS']
-
$_SERVER['REMOTE_HOST']
-
$_SERVER['PATH_INFO']
-
$_SERVER['QUERY_STRING']
Pregunta 71
Pregunta
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.
Respuesta
-
$_SERVER['SERVER_NAME']
-
$_SERVER['REMOTE_ADDRESS']
-
$_SERVER['REMOTE_HOST']
-
$_SERVER['PATH_INFO']
-
$_SERVER['QUERY_STRING']
Pregunta 72
Pregunta
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
Respuesta
-
$_SERVER['SERVER_NAME']
-
$_SERVER['REMOTE_ADDRESS']
-
$_SERVER['REMOTE_HOST']
-
$_SERVER['PATH_INFO']
-
$_SERVER['QUERY_STRING']
Pregunta 73
Pregunta
This auto-global built-in array variablewhich provides the Web site name of the server computer where the PHP interpreter is running.
Respuesta
-
$_SERVER['SERVER_NAME']
-
$_SERVER['REMOTE_ADDRESS']
-
$_SERVER['REMOTE_HOST']
-
$_SERVER['PATH_INFO']
-
$_SERVER['QUERY_STRING']
Pregunta 74
Pregunta
What does PHP stands for
Respuesta
-
Personal Hypertext Processor
-
PHP: Hypertext Preprocessor
-
Private Home Page
-
Private Hypertext Preprocessor
Pregunta 75
Pregunta
What does S in BASE refers to?
Respuesta
-
System Consistence
-
System Availability
-
Changing System
-
System Stability
Pregunta 76
Pregunta
[What does the term "I" expands to in the term "ACID"?
Respuesta
-
Isolated
-
Inseparable
-
Indispensable
-
Insulted
Pregunta 77
Pregunta
What does XML stand for?
Respuesta
-
eXtensible Markup Language
-
Example Markup Language
-
X-Markup Language
-
eXtra Modern Link
Pregunta 78
Pregunta
What does XSL stand for?
Respuesta
-
eXtensible Stylesheet Language
-
eXtra Style Language
-
eXpandable Style Language
-
eXtensible Style Listing
Pregunta 79
Pregunta
What is the correct syntax of the declaration which defines the XML version?
Respuesta
-
<?xml version="1.0" />
-
<?xml version="1.0"?>
-
<xml version="1.0" />
Pregunta 80
Pregunta
Which company did Cassandra was primarily developed in?
Respuesta
-
Apache
-
Facebook
-
Google
-
Amazon
Pregunta 81
Pregunta
Which feature of CAP refers to load balancing
Respuesta
-
None of these
-
С
-
А
-
Р
Pregunta 82
Pregunta
Which of the following are the simplest NoSQL databases
Respuesta
-
Key-value
-
Wide-column
-
Document
-
All of the mentioned
Pregunta 83
Pregunta
Which of the following is correct about PHP
Respuesta
-
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
Pregunta 84
Pregunta
Which of the following is correct about variable naming rules?
Respuesta
-
Variable names must begin with a letter or underscore character.
-
A variable name can consist of numbers, letters, underscores.
-
you cannot use characters like + , - , % , ( , ) . & , etc in a variable name.
-
All of these statement
Pregunta 85
Pregunta
Which of the following is not a NoSQL database?
Respuesta
-
SQL Server
-
MongoDB
-
Cassandra
-
None of the mentioned
Pregunta 86
Pregunta
Which of the following method can be used to create a MySql database using PHP?
Respuesta
-
mysql_connect()
-
mysql_query()
-
mysql_close()
-
None of the above
Pregunta 87
Pregunta
Which of them could not be applied to techniques for looping through arrays in PHP
Respuesta
-
$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');
Pregunta 88
Pregunta
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.
Respuesta
- True
- False
Pregunta 89
Pregunta
A large database typically has large transaction volumes and rates, is used in service sector industries, and runs 24/7
Respuesta
- True
- False
Pregunta 90
Pregunta
A library of functions, also known as an application programming interface (API), is used to access the database
Respuesta
- True
- False
Pregunta 91
Pregunta
A safer way to do inserts and other queries is through the use of placeholders (specified by the ? symbol) in PHP
Respuesta
- True
- False
Pregunta 92
Pregunta
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.
Respuesta
- True
- False
Pregunta 93
Pregunta
In SQLJ, an iterator is a type of object associated with a collection (set or multiset) of records in a query result.
Respuesta
- True
- False
Pregunta 94
Pregunta
In SQLJ, embedded SQL commands are preceded by #sql.
Respuesta
- True
- False
Pregunta 95
Pregunta
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.
Respuesta
- True
- False
Pregunta 96
Pregunta
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.
Respuesta
- True
- False
Pregunta 97
Pregunta
Numeric array − An array with a numeric index. Values are stored and accessed in linear fashion.
Respuesta
- True
- False
Pregunta 98
Pregunta
OPEN CURSOR command is issued to indicate that we are done with processing the result of the query associated with that cursor.
Respuesta
- True
- False
Pregunta 99
Pregunta
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.
Respuesta
- True
- False
Pregunta 100
Pregunta
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
Respuesta
- True
- False
Pregunta 101
Pregunta
The typical mechanisms for making an object persistent are naming and reachability
Respuesta
- True
- False
Pregunta 102
Pregunta
XML attribute values must always be enclosed in quotes
Respuesta
- True
- False
Pregunta 103
Pregunta
XML elements cannot be empty
Respuesta
- True
- False
Pregunta 104
Pregunta
XML's goal is to replace HTML
Respuesta
- True
- False
Pregunta 105
Pregunta
XQuery is the language for querying XML data
Respuesta
- True
- False
Pregunta 106
Pregunta
The case represents a single superclass/subclass relationship with more than one superclass, where the superclasses represent different entity types
Respuesta
-
disjoint
-
joint
-
overlapping
-
union
Pregunta 107
Pregunta
When a database design is in ____________, each value in a tuple is in atomic value.
Respuesta
-
First normal form
-
Second normal form
-
Third normal form
-
Forth normal form
Pregunta 108
Pregunta
Redundancy leads to three potential problems. Briefly describe each of the three.
Respuesta
-
Duplication of effort
-
Storage space is wasted
-
Multiple occurrences of data may become inconsistent
Pregunta 109
Pregunta
What two things does minimizing redundancy imply
Respuesta
-
Minimizing redundant storage of the same information.
-
Reducing the need for multiple updates to maintain consistency across multiple copies of the same information.
Pregunta 110
Pregunta
What are the four informal guidelines that may be used to measure the quality of a relation schema design?
Respuesta
-
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.
Pregunta 111
Pregunta
What are the three goals of database design?
Respuesta
-
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
Pregunta 112
Pregunta
Identify two of the three factors to consider in choosing one DBMS over another
Respuesta
-
Organization-wide adoption of a certain philosophy (data model, vendor, methodology, tools).
-
Familiarity of personnel with the system
-
Availability of vendor services
Pregunta 113
Pregunta
Identify the three criteria to guide the choice of physical database design options
Respuesta
-
Response time.
-
Space utilization
-
Transaction throughput.
Pregunta 114
Pregunta
A join operation joins _____ tables into _____.
Respuesta
-
three, two
-
three, one
-
four, two
-
two, one
Pregunta 115
Pregunta
A primary key should be defined as:
I. NULL
II. NOT NULL
III. Optional
Respuesta
-
I, II
-
I, III
-
II only
-
I, II, III
Pregunta 116
Pregunta
A subquery in an SQL SELECT statement is enclosed in:
Respuesta
-
braces -- {...}.
-
CAPITAL LETTERS
-
parenthesis -- (...)
-
brackets -- [...].
Pregunta 117
Pregunta
SQL query and modification commands make up a(n) ________ .
Respuesta
-
DML
-
DDL
-
HTML
-
XML
Pregunta 118
Pregunta
The command to eliminate a table from a database is:
Respuesta
-
• REMOVE TABLE TableName
-
• DROP TABLE TableName
-
• DELETE TABLE TableName
-
• UPDATE TABLE TableName
Pregunta 119
Pregunta
________ stores are used to store information about networks, such as social connections.
Respuesta
-
• Key-value
-
• Wide-column
-
• Graph
Pregunta 120
Pregunta
A ___________ is an indirect functional dependency, one in which X->Z only by virtue of X->Y and Y->Z
Respuesta
-
• Multivalued Dependencies
-
• Join Dependency
-
• Trivial Functional Dependency
-
• Transitive Dependencies
Pregunta 121
Pregunta
A table is in 3NF if it is in 2NF and if it has no ____________
Respuesta
-
• Functional Dependencies
-
• Transitive Dependencies
-
• Trivial Functional Dependency
-
• Multivalued Dependencies
Pregunta 122
Pregunta
A table is in BCNF if it is in 3NF and if every determinant is a ___________ key.
Respuesta
-
• Dependent
-
• Normal
-
• Candidate
-
Both Normal and Candidate
Pregunta 123
Pregunta
Anomalies are avoided by splitting the offending relation into multiple relations, is also known as
Respuesta
-
• Accupressure
-
• Decomposition
-
• Both Decomposition and Precomposition
-
• Precomposition
Pregunta 124
Pregunta
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:
Respuesta
-
A-->B
-
A-->C
-
A-->(B,C)
-
(B,C)-->A
Pregunta 125
Pregunta
For select operation the ________ appear in the subscript and the ___________ argument appears in the parenthesis after the sigma.
Respuesta
-
• Predicates, relation
-
• Relation, Predicates
-
• Operation, Predicates
-
• Relation, Operation
Pregunta 126
Pregunta
If X -> Y, which of the following would make Y fully dependent on X?
Respuesta
-
• X consists of multiple attributes
-
• Y is a single attribute
-
• Y consists of multiple attributes
-
• X is a single attribute
Pregunta 127
Pregunta
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.
Respuesta
-
• Candidate
-
• Join
-
• Functional
-
• None of the Mentioned
Pregunta 128
Pregunta
In EER modeling, specialization is the process of generating
Respuesta
-
• entities out of attributes
-
• attributes out of entities
-
• subclasses out of superclasses
-
• superclasses out of subclasses
Pregunta 129
Pregunta
In precedence of set operators the expression is evaluated from
Respuesta
-
• Left to left
-
• Left to right
-
• Right to left
-
• From user specification
Pregunta 130
Pregunta
The ___________ operation, denoted by −, allows us to find tuples that are in one relation but are not in another.
Respuesta
-
• Union
-
• Set-difference
-
• Difference
-
• Intersection
Pregunta 131
Pregunta
The functional dependency X -> Y is true if
Respuesta
-
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
Pregunta 132
Pregunta
The result of a set difference operation r - s will be
Respuesta
-
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
Pregunta 133
Pregunta
What does a projection operation do?
Respuesta
-
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.
Pregunta 134
Pregunta
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)
Respuesta
-
Transitive Dependency
-
Insertion Anomaly
-
Referential Integrity Constraint
-
Normal Form
Pregunta 135
Pregunta
Which is a join condition contains an equality operator
Respuesta
-
Equijoins
-
Cartesian
-
Natural
-
Left
Pregunta 136
Pregunta
Which is a unary operation
Respuesta
-
Selection operation
-
Primitive operation
-
Projection operation
-
Generalized selection
Pregunta 137
Pregunta
Which of the following is a fundamental operation in relational algebra
Respuesta
-
Set intersection
-
Natural join
-
Assignment
-
None of the mentioned
Pregunta 138
Pregunta
Which of the following is not a restriction for a table to be a relation?
Respuesta
-
The cells of the table must contain a single value
-
The columns must be ordered
-
No two rows in a table may be identical
Pregunta 139
Pregunta
Which of the following is used to denote the selection operation in relational algebra?
Respuesta
-
Pi
-
Sigma
-
Lambda
-
Omega
Pregunta 140
Pregunta
Y is transitively dependent on X, if
Respuesta
-
X -> A, B and Y -> A, B
-
X -> Y and A -> Y
-
X -> A, B and A -> Y
-
X -> Y and Y -> A
Pregunta 141
Pregunta
For two tables to be union compatible, corresponding columns from each table should have which of the following?
Respuesta
-
the same domain
-
the same name
-
different domains
-
different names
¿Quieres crear tus propios Tests gratis con GoConqr? Más información.