SDP 6 (2)

Beschreibung

- at Quiz am SDP 6 (2), erstellt von хомяк убийца am 17/12/2017.
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12

Zusammenfassung der Ressource

Frage 1

Frage
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
Antworten
  • o LEFT OUTER JOIN
  • o RIGHT OUTER JOIN
  • o FULL OUTER JOIN
  • o LEFT INNER JOIN

Frage 2

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

Frage 3

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

Frage 4

Frage
UML _________ diagrams describe the dynamic relationships among components
Antworten
  • o Behavioral
  • o Structural
  • o Class
  • o Direct

Frage 5

Frage
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
Antworten
  • o persistent object
  • o instance variable
  • o attribute
  • o object structure

Frage 6

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

Frage 7

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

Frage 8

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

Frage 9

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

Frage 10

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

Frage 11

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

Frage 12

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

Frage 13

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

Frage 14

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

Frage 15

Frage
_______occurs when the same data is stored multiple times
Antworten
  • o Redundancy
  • o Normalisation
  • o Denormalization
  • o Persistent

Frage 16

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

Frage 17

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

Frage 18

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

Frage 19

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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.
Antworten
  • True
  • False

Frage 20

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

Frage 21

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

Frage 22

Frage
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).
Antworten
  • True
  • False

Frage 23

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

Frage 24

Frage
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
Antworten
  • True
  • False

Frage 25

Frage
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
Antworten
  • True
  • False

Frage 26

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

Frage 27

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

Frage 28

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

Frage 29

Frage
Multi-line PHP comments start with // and end with #.
Antworten
  • True
  • False

Frage 30

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

Frage 31

Frage
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>
Antworten
  • True
  • False

Frage 32

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

Frage 33

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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
Antworten
  • True
  • False

Frage 34

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

Frage 35

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

Frage 36

Frage
How can you change "Hansen" into "Nilsen" in the "LastName" column in the Persons table?
Antworten
  • 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'

Frage 37

Frage
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?
Antworten
  • 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');

Frage 38

Frage
What is the correct order of clauses for a proper SQL query?
Antworten
  • 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

Frage 39

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

Frage 40

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

Frage 41

Frage
Which of the following DROP statements is INCORRECT?
Antworten
  • • DROP TABLE
  • • DROP DATABASE
  • • DROP ROW
  • • DROP INDEX

Frage 42

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

Frage 43

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

Frage 44

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

Frage 45

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

Frage 46

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

Frage 47

Frage
With SQL, how can you return all the records from a table named "Persons" sorted descending by "FirstName"?
Antworten
  • 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

Frage 48

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

Frage 49

Frage
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"?
Antworten
  • 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*';

Frage 50

Frage
With SQL, how do you select all the records from a table named "Persons" where the "FirstName" is "Alma" and the "LastName" is "Alimova"?
Antworten
  • 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'

Frage 51

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

Frage 52

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

Frage 53

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

Frage 54

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

Frage 55

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

Frage 56

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

Frage 57

Frage
How will you close a MySql database using PHP?
Antworten
  • mysql_destroy
  • mysql_exit
  • mysql_end
  • mysql_close

Frage 58

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

Frage 59

Frage
How will you connect a MySql database using PHP?
Antworten
  • mysql_connection
  • mysql_query
  • mysql_fetch_array
  • mysql_connect

Frage 60

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

Frage 61

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

Frage 62

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

Frage 63

Frage
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.
Antworten
  • I,II
  • I,II,III
  • II,III
  • I,III

Frage 64

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

Frage 65

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

Frage 66

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

Frage 67

Frage
Point out the wrong statement
Antworten
  • 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

Frage 68

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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"
Antworten
  • d, disjoint
  • j, joint
  • o, overlapping
  • u, union

Frage 69

Frage
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})
Antworten
  • disjoint
  • joint
  • overlapping
  • union

Frage 70

Frage
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.
Antworten
  • $_SERVER['SERVER_NAME']
  • $_SERVER['REMOTE_ADDRESS']
  • $_SERVER['REMOTE_HOST']
  • $_SERVER['PATH_INFO']
  • $_SERVER['QUERY_STRING']

Frage 71

Frage
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.
Antworten
  • $_SERVER['SERVER_NAME']
  • $_SERVER['REMOTE_ADDRESS']
  • $_SERVER['REMOTE_HOST']
  • $_SERVER['PATH_INFO']
  • $_SERVER['QUERY_STRING']

Frage 72

Frage
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
Antworten
  • $_SERVER['SERVER_NAME']
  • $_SERVER['REMOTE_ADDRESS']
  • $_SERVER['REMOTE_HOST']
  • $_SERVER['PATH_INFO']
  • $_SERVER['QUERY_STRING']

Frage 73

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

Frage 74

Frage
What does PHP stands for
Antworten
  • Personal Hypertext Processor
  • PHP: Hypertext Preprocessor
  • Private Home Page
  • Private Hypertext Preprocessor

Frage 75

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

Frage 76

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

Frage 77

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

Frage 78

Frage
What does XSL stand for?
Antworten
  • eXtensible Stylesheet Language
  • eXtra Style Language
  • eXpandable Style Language
  • eXtensible Style Listing

Frage 79

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

Frage 80

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

Frage 81

Frage
Which feature of CAP refers to load balancing
Antworten
  • None of these
  • С
  • А
  • Р

Frage 82

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

Frage 83

Frage
Which of the following is correct about PHP
Antworten
  • 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

Frage 84

Frage
Which of the following is correct about variable naming rules?
Antworten
  • 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

Frage 85

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

Frage 86

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

Frage 87

Frage
Which of them could not be applied to techniques for looping through arrays in PHP
Antworten
  • $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');

Frage 88

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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.
Antworten
  • True
  • False

Frage 89

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

Frage 90

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

Frage 91

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

Frage 92

Frage
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.
Antworten
  • True
  • False

Frage 93

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

Frage 94

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

Frage 95

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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.
Antworten
  • True
  • False

Frage 96

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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.
Antworten
  • True
  • False

Frage 97

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

Frage 98

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

Frage 99

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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.
Antworten
  • True
  • False

Frage 100

Frage
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
Antworten
  • True
  • False

Frage 101

Frage
The typical mechanisms for making an object persistent are naming and reachability
Antworten
  • True
  • False

Frage 102

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

Frage 103

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XML elements cannot be empty
Antworten
  • True
  • False

Frage 104

Frage
XML's goal is to replace HTML
Antworten
  • True
  • False

Frage 105

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XQuery is the language for querying XML data
Antworten
  • True
  • False

Frage 106

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

Frage 107

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

Frage 108

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

Frage 109

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

Frage 110

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What are the four informal guidelines that may be used to measure the quality of a relation schema design?
Antworten
  • 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.

Frage 111

Frage
What are the three goals of database design?
Antworten
  • 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

Frage 112

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

Frage 113

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

Frage 114

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

Frage 115

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

Frage 116

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

Frage 117

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

Frage 118

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

Frage 119

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

Frage 120

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

Frage 121

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

Frage 122

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

Frage 123

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

Frage 124

Frage
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:
Antworten
  • A-->B
  • A-->C
  • A-->(B,C)
  • (B,C)-->A

Frage 125

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

Frage 126

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

Frage 127

Frage
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.
Antworten
  • • Candidate
  • • Join
  • • Functional
  • • None of the Mentioned

Frage 128

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

Frage 129

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

Frage 130

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

Frage 131

Frage
The functional dependency X -> Y is true if
Antworten
  • 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

Frage 132

Frage
The result of a set difference operation r - s will be
Antworten
  • 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

Frage 133

Frage
What does a projection operation do?
Antworten
  • 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.

Frage 134

Frage
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)
Antworten
  • Transitive Dependency
  • Insertion Anomaly
  • Referential Integrity Constraint
  • Normal Form

Frage 135

Frage
Which is a join condition contains an equality operator
Antworten
  • Equijoins
  • Cartesian
  • Natural
  • Left

Frage 136

Frage
Which is a unary operation
Antworten
  • Selection operation
  • Primitive operation
  • Projection operation
  • Generalized selection

Frage 137

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

Frage 138

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

Frage 139

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

Frage 140

Frage
Y is transitively dependent on X, if
Antworten
  • X -> A, B and Y -> A, B
  • X -> Y and A -> Y
  • X -> A, B and A -> Y
  • X -> Y and Y -> A

Frage 141

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