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sdp 6

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Quiz on sdp 6 , created by Жарас Мергазы on 16/12/2017.
Жарас Мергазы
Quiz by Жарас Мергазы, updated more than 1 year ago
Жарас Мергазы
Created by Жарас Мергазы almost 7 years ago
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Resource summary

Question 1

Question
The PEAR DB functions can be accessed using DB::<function_name>.
Answer
  • True
  • False

Question 2

Question
The string argument of the function for connecting to a database is of the format <DBMS software>://<user account>:<password>@<database server>
Answer
  • True
  • False

Question 3

Question
The PEAR DB functon for connecting to a database is called DB::linkto database('string').
Answer
  • True
  • False

Question 4

Question
• The DBMS software in <DBMS software>://<user account>:<password>@<database server> stands for the particular DBMS software package being connected to: for example mysqli for versions of MySQL starting with version 4.1.2
Answer
  • True
  • False

Question 5

Question
• The PEAR DB function DB::is Error can be used to determine whether any database access operation was successful or not.
Answer
  • True
  • False

Question 6

Question
• In PHP, an _____ array provides pairs of key=>value elements; the value of an element is referenced through its key and all key values in a particular array must be unique.
Answer
  • Numeric
  • Value
  • String
  • Associative

Question 7

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

Question 8

Question
• PHP 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 9

Question
• The PHP start tag is <?php and end the tag is ?>.
Answer
  • True
  • False

Question 10

Question
• Web pages, where part of the information is extracted from databases or other data source, are called dynamic Web pages
Answer
  • True
  • False

Question 11

Question
• In PHP, a ____ array associates a numeric index with each element in the array
Answer
  • Numeric
  • Associated
  • Variable
  • String

Question 12

Question
• PHP variable names start with a $ sign and can include characters, numbers, and the underscore character
Answer
  • True
  • False

Question 13

Question
• Interpolating variables occurs only within single-quoted strings.
Answer
  • True
  • False

Question 14

Question
• PHP programs are executed on the client.
Answer
  • True
  • False

Question 15

Question
• The auto-global predefined PHP variable $_POST is an array that holds all the values entered through form parameters.
Answer
  • True
  • False

Question 16

Question
• JDBC does not distinguish between queries that return single tuples and those that return multiple tuples.
Answer
  • True
  • False

Question 17

Question
• The JDBC _____ libraries are called java.sql.*
Answer
  • Method
  • Function
  • Class

Question 18

Question
• What are the advantages and disadvantages of the embedded SQL approach.
Answer
  • The main advantage is the query text is part of the source code can be checked for syntax errors and validated against the database schema at compile time. The program is quite readable. Since queries are known in advance, the choice of program variables to hold query results is simple.
  • The main advantage is flexibility in generating queries at runtime. Also, the library of function calls approach is able to call multiple data program.
  • The main disadvantage is the query text is part of the source code can be checked for syntax errors and validated against the database schema at compile time. The program is quite readable. Since queries are known in advance, the choice of program variables to hold query results is simple.
  • Disadvantage are more complex programming, inability to do checking at compile time, and concerns about SQL runtime errors.
  • Disadvantage are the loss of flexibility in changing the query the query at runtime and that all changes to queries must be recompiled.

Question 19

Question
• The use of function calls is a more dynamic approach for database programming than embedded SQL.
Answer
  • True
  • False

Question 20

Question
• A _____ object is similar to a cursor in embedded SQL and an iterator in SQLJ.
Answer
  • Procedure
  • Function call
  • Result Set

Question 21

Question
• _____ is the part of the SQL standard that specifies how to write persistent stored modules.
Answer
  • SQL/PSM
  • XML
  • SQLJ
  • ResultSet

Question 22

Question
• Database stored procedures (aka persistent stored modules) are stored and executed by the DBMS at the database server.
Answer
  • True
  • False

Question 23

Question
• Discuss advantages and diadvantages to the library of function calls approach
Answer
  • Disadvantage are the loss of flexibility in changing the query at runtime and that all changes to queries must be recompiled.
  • The main advantage is flexibility in generating queries at runtime. Also, the library of function calls approach is able to call multiple data program.
  • The main advantage is flexibility in generating queries at compile time. Also, the library of function calls approach is able to call multiple single program.
  • Disadvantages are more complex programming, inability to do checking at compile time, and concerns about SQL runtime errors.
  • The main advantage is the query text is part of source code and can be checked for syntax errors and validated against the data. The program is quite readable.

Question 24

Question
• It is necessary to have a binding between the data types of the programming language and the attribute data types in the data model
Answer
  • True
  • False

Question 25

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

Question 26

Question
• One advantage of using an SQLJ translator is that it is not necessary to install drivers such as a JDBC driver.
Answer
  • True
  • False

Question 27

Question
• Describe the three main approaches for database programming.
Answer
  • • Using a library of database functions. This approach provides what is known as an application programming interface (API) for accessing a database from applications programs.
  • • Using a library of database methods. This approach provides what is known as an application programming interface (API) for accessing a database from applications programs
  • • Embedded SQL. Embeding database commands in a general-purpose programming language. A preprocessor extracts the embedded SQL from the source code and replaces it with function calls to DBMS-generated code.
  • • Embedded SQL. Embeding database commands in a specific-purpose programming language. A preprocessor can not extract code, but function calls to be extracted to DBMS-generated code.
  • • Designing a new database programming language.
  • • Embedded SQL. Embeding database commands in a specific-purpose programming language. A preprocessor extracts the embedded SQL from the source code and replaces it with function calls to DBMS-generating code

Question 28

Question
• In XML _____ defines the set of commands (names) that can be used
Answer
  • • Namespace
  • • Valid
  • • Document
  • • Invalid

Question 29

Question
• In XML schema, the tag _____ is used tospecify primary keys.
Answer
  • • xs:element
  • • xsd:key
  • • psd:schema
  • • xs:sequence

Question 30

Question
• A * following an element name means the element can be repeated zero or one times (an optional, single-valued, nonrepeating elements)
Answer
  • True
  • False

Question 31

Question
• If an XML document is well-formed and follows a particular schema, it is _____
Answer
  • • Namespace
  • • Keys
  • • Invalid
  • • Valid

Question 32

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

Question 33

Question
• An element that does not have *, +, or ? following the element name means the element must appear exactly once in the document (a required, single-valued, nonrepeating element).
Answer
  • True
  • False

Question 34

Question
• A ? following an element name means that element can be repeated zero or more times in the document (an optional, mult-valued, repeating element).
Answer
  • True
  • False

Question 35

Question
• The basic object in XML is the XML document, which is structured using types and iterators.
Answer
  • True
  • False

Question 36

Question
• How does a well-formed XML document look like?
Answer
  • • It is syntactically correct: a non-single root element with every element including a matching pair of start/end tags within the start-end of the parent element
  • • It must finish with an XML declaration to indicate the version of XML.
  • • It is syntactically correct: a single root element with every element including a matching pair of start/end tags within the start-end tags of the parent element
  • • It is syntactically correct: a single root element with every element except a matching pair of start/end tags within the start-end tags of the parent elements
  • • It must start with an XML declaration to indicate the version of XML

Question 37

Question
• Struct type constructors include the set (T), list (T), bag(T), array(T), and dictionary (K,T) type constructors.
Answer
  • True
  • False

Question 38

Question
• Three major differences between the relational and object database design.
Answer
  • • In ODB design a binary relationship can be declared in one direction or both. If attributes are included in both directions, there is a potential problem with redundancy.
  • • In ODB design a binary relationship can be declared in one direction or both. If attributes are included in both directions, there is no any problem
  • • In an ODB, operations must be defined early since they are part of the classes specifications. In RDBs, operations may not be defined until implementation
  • • In RDB inheritance is built into the model; ODBs do not have built-in constructs for inheritance.
  • • In an RDB, operations must be defined early since they are part of the class specifications. In an ODB, operations may not be defined until implementation
  • • In ODB inheritance is built into the model; RDBs do not have built-in constructs for inheritance.

Question 39

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

Question 40

Question
• The main property required of an OID is that it be immutable (should not change).
Answer
  • True
  • False

Question 41

Question
• _____ inheritance occurs when a subtype inherits only some of the functions of a supertype.
Answer
  • • Generalisation
  • • Complete encapsulation
  • • Conditional
  • • Selective

Question 42

Question
• In operator overloading (or polymorphism), an operation name may refer to several distinct implementations, depending on the type of object it is applied to.
Answer
  • True
  • False

Question 43

Question
• In ______ all operations that can be applied to an object must be predefined.
Answer
  • • Half encapsulation
  • • Complete encapsulation
  • • Object identifier
  • • Feedback loop

Question 44

Question
• The implementation of an operation is called its signature.
Answer
  • True
  • False

Question 45

Question
• A subtype is used when a new type is needed that is similar but not identical to an already defined type.
Answer
  • True
  • False

Question 46

Question
• The dictionary constructor creates a collection of two tupes (K,V) where the value of a key K can be used to retrieve the can be used to retrieve the corresponding value V.
Answer
  • True
  • False

Question 47

Question
• An ODMS provides a unique identity to each independent object in the database via a unique, system-generated ____.
Answer
  • • Selective
  • • Complete encaplsulation
  • • Object identifier

Question 48

Question
• An object typically has three components: state, timing, and behavior
Answer
  • True
  • False

Question 49

Question
• The 80-20 rule suggests that 80% of the workload is presented by 20% of the most frequently used transactions, which govem the physical database design.
Answer
  • True
  • False

Question 50

Question
• The phases (or activities) of the life cycle are not strictly in sequence; ______ are common among and within the phases of the life cycle.
Answer
  • • One-shot
  • • Requirements collection
  • • Feedback loop
  • • View integration

Question 51

Question
• In the _____ approach to schema design, a scheme is designed for each user group or application based phase, these schemas are merged into a global conecptual schema.
Answer
  • • Requirements analysis
  • • Feedback loops
  • • Feasibility analysis
  • • One-shot
  • • View integration

Question 52

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 53

Question
• Many organizations use data dictionary systems (information repositories) to manage meta-data, i.e., data that describes the database structure, constraints, applications, authorizations, users, and so forth.
Answer
  • True
  • False

Question 54

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

Question 55

Question
• _______ involves interacting with potential users and user groups to identify their particular problems and needs.
Answer
  • • view-integration
  • • requirements collection and analysis
  • • feasibility analysis
  • • one-shot
  • • feedback loop

Question 56

Question
• A transaction processing system can be characterized as one with several dozen gigabytes of data and a schema with more than 30 or 40 distinct entity types
Answer
  • True
  • False

Question 57

Question
• Identify the three criteria to guide the choice of physical database design options
Answer
  • • Space utisilation
  • • Availability of vendor services
  • • Transaction throughput
  • • Response time
  • • Familiarity of personnel with the system

Question 58

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

Question 59

Question
• _____ is concerned with analyzing potential application areas, identifying the economics of information gathering and dissemination, performing preiliminary cost-benefit studies, determining the complexity of data and processes, and setting up priorities among applications.
Answer
  • • Feasibility analysis
  • • Requirements collection and analysis
  • • View integration
  • • One-shot
  • • Feedback loops

Question 60

Question
• The initial requirements can be expected to be formal, complete, consistent, and correct.
Answer
  • True
  • False

Question 61

Question
• In the ______ schema design approach, the requirements from the different stakeholders are merged into a single set of requirements before the schema design begins.
Answer
  • • Requirements collection
  • • Feedback loop
  • • Centralized (or one-shot)
  • • Requirements analysis

Question 62

Question
• What two things does minimizing redundancy imply?
Answer
  • • Reducing the need for multiple updates to maintain consistency across multiple copies of the same information.
  • • Reducing the redundant information in tuples.
  • • Making sure the semantics of the attributes is clear in the schema
  • • Minimizing redundant storage of the same information
  • • Disallowing the possibility of generating spurious tuples

Question 63

Question
• Third normal form (3NF): R is 2NF and all non-prime attributes are transively dependent on the primary key.
Answer
  • True
  • False

Question 64

Question
• First normal from (1NF): the domain of an attribute must include only atomic (simple, indivisible, scalar) values and the value of any attribute ina tuple must be a single value from the domain of that attribute.
Answer
  • True
  • False

Question 65

Question
A functional dependency is a property of the relation schema R not of a particular legal relation state r or R, therefor it must understands the semantics of the attributes of R.
Answer
  • True
  • False

Question 66

Question
Second normal form (2NF): R is 1NF and every non-prime attribute A in R is fully functionally dependent on the primary key of R
Answer
  • True
  • False

Question 67

Question
What are four informal guidelines that may be used to measure the quality of a relation schema design?
Answer
  • Reducing the need for multiple updates to maintain consistency across multiple copies of the same information.
  • • Disallowing the possibility of generating spurious tuples.
  • • Reducing the redundant information in tuples
  • • Reducing the NULL values in tuples
  • • Making sure the semantics of the attributes is clear in the schema
  • • Minimizing redundant storage of the same information

Question 68

Question
Normalization of data can be considered a process of analyzing the given relation schemas based on their functional dependencies and primary keys to achieve closure on the domain space
Answer
  • True
  • False

Question 69

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 perticipating entity types (their combination in S is the composite primary key of S).
Answer
  • True
  • False

Question 70

Question
The symbol σ (sigma) is used to denote the SELECT operator in the relational algebra
Answer
  • True
  • False

Question 71

Question
A EQUIJOIN uses any of the comparison operators =, <, ≤, >, ≥, or ≠.
Answer
  • True
  • False

Question 72

Question
The symbol π (pi) is used to denote the PROJECT operation in the relational algebra.
Answer
  • True
  • False

Question 73

Question
A THETA JOIN uses the comparison operator =
Answer
  • True
  • False

Question 74

Question
SQL is both a data definition language (DDL) and a data manipulation language (DML).
Answer
  • True
  • False

Question 75

Question
A key uniquely identifies a tuple in a relation
Answer
  • True
  • False

Question 76

Question
When the DELETE operation violates a contraint, the deletion must be rejected.
Answer
  • True
  • False

Question 77

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

Question 78

Question
If a multi-table query refers to two or more attributes with the same name, we must qualify the attribute name with the table name, e.g., TABLE.Attribute, to prevent ambiguity.
Answer
  • True
  • False

Question 79

Question
A relation schema may only have one key.
Answer
  • True
  • False

Question 80

Question
Tuples in a relation are ordered.
Answer
  • True
  • False

Question 81

Question
The DELETE operation can violate referential integrity.
Answer
  • True
  • False

Question 82

Question
The INSERT operation can violate domain constraints, key constraints, entity integrity, or referential integrity.
Answer
  • True
  • False

Question 83

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

Question 84

Question
Attributes that represent the same real-world concept must have identical names in different relations.
Answer
  • True
  • False

Question 85

Question
When the INSERT operation violates a constraint, the default option is to reject the insertion.
Answer
  • True
  • False

Question 86

Question
Attributes must have unique domains.
Answer
  • True
  • False

Question 87

Question
NULL values may mean value unknown, value exits but is not available, attribute does not apply to this tuple (value undefined).
Answer
  • True
  • False

Question 88

Question
All tuples in a relation must be distinct.
Answer
  • True
  • False

Question 89

Question
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 90

Question
The _____ is a collection of several libraries of functions for enhancing PHP.
Answer
  • DBMS
  • PHP Extension and Application Repository (PEAR)
  • MYSQL
  • PHP SQL

Question 91

Question
The _____ variable is similar to cursor and iterator variables.
Answer
  • $d->query
  • post
  • $r

Question 92

Question
The abend function can be used to terminate a PHP program if there is an error.
Answer
  • True
  • False

Question 93

Question
The PHP function $d->nextID creates a sequence of unique values for a particular table.
Answer
  • True
  • False

Question 94

Question
Creating a database design that only stores each logical data item in only one place in the database
Answer
  • Normalization
  • Relational data model
  • Data abstraction
  • Redundancy

Question 95

Question
Stores catalog information about schemas and constraints, design decisions, usage standards, application program descriptions, and user information
Answer
  • Data dictionary (or data repository system or information repository)
  • Relational data model
  • Atomicity property
  • Data abstraction

Question 96

Question
Data that is derived from the database files but not explicitly stored
Answer
  • Relationship
  • Relational data model
  • Virtual data
  • Virtual date

Question 97

Question
Represents an association among two or more entities
Answer
  • . Relationship
  • Relational data model
  • Data abstraction
  • Redundancy

Question 98

Question
Represents a database as a collection of tables, where each table can be stored as a separate file
Answer
  • Data abstraction
  • Atomicity property
  • Redundancy
  • Relational data model

Question 99

Question
Ensures that either all the database operations in a transaction are executed or none are
Answer
  • Atomicity property
  • Atomic property
  • Redundancy
  • Data abstraction

Question 100

Question
Storing the same data multiple times
Answer
  • Redundancy
  • Data abstraction
  • Relationship
  • Virtual data

Question 101

Question
Characteristic that allows program-data independence and program-operation independence
Answer
  • Redundancy
  • Data abstraction
  • Relationship
  • Relational data model

Question 102

Question
Choose correct answer
Image:
1 (binary/octet-stream)
Answer

Question 103

Question
Choose correct answer!!
Image:
1 (binary/octet-stream)
Answer

Question 104

Question
Choose one
Image:
12222 (binary/octet-stream)
Answer

Question 105

Question
is typically used to loop over the tuples in a query result
Answer
  • cursor
  • named
  • positional
  • Impedance mismatch

Question 106

Question
iterator is associated with a query result in SQLJ by listing the attribute names and types that appear in the query
Answer
  • named
  • cursor
  • Impedance mismatch
  • positional

Question 107

Question
iterator lists only the attribute types that appear in a query result in SQLJ.
Answer
  • positional
  • Impedance mismatch
  • named
  • cursor

Question 108

Question
is the term used to refer to the problems that occur because of differences between the database model and language model
Answer
  • Impedance mismatch
  • positional
  • named
  • cursor

Question 109

Question
Used to choose a subset of the tuples from a relation that satisfies a selection condition
Answer
  • • LEFT OUTER JOIN
  • • SELECT
  • • PROJECT
  • • JOIN
  • • INTERSECTION

Question 110

Question
Selects certain columns from the table and discards the other columns
Answer
  • • PROJECT
  • • SELECT
  • • LEFT OUTER JOIN
  • • JOIN
  • • INTERSECTION

Question 111

Question
= R S keeps every tuple in the first (left) relation R; if no matching tuples is found in S, then the attributes of S in the join filled with NULL values
Answer
  • • LEFT OUTER JOIN
  • • SELECT
  • • PROJECT
  • • JOIN
  • • INTERSECTION

Question 112

Question
R S in the relational algebra combines related tuples in R and S
Answer
  • • JOIN
  • • INTERSECTION
  • • LEFT OUTER JOIN
  • • PROJECT
  • • SELECT

Question 113

Question
R S in the relational algebra includes all tuples in both R and S
Answer
  • • JOIN
  • • INTERSECTION
  • • LEFT OUTER JOIN
  • • PROJECT
  • • SELECT
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