sdp 6

Descrição

Quiz sobre sdp 6 , criado por Жарас Мергазы em 16-12-2017.
Жарас Мергазы
Quiz por Жарас Мергазы, atualizado more than 1 year ago
Жарас Мергазы
Criado por Жарас Мергазы quase 7 anos atrás
972
10

Resumo de Recurso

Questão 1

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

Questão 2

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

Questão 3

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

Questão 4

Questão
• 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
Responda
  • True
  • False

Questão 5

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

Questão 6

Questão
• 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.
Responda
  • Numeric
  • Value
  • String
  • Associative

Questão 7

Questão
• Multi-line PHP comments start with // and end with #.
Responda
  • True
  • False

Questão 8

Questão
• 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
Responda
  • True
  • False

Questão 9

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

Questão 10

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

Questão 11

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

Questão 12

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

Questão 13

Questão
• Interpolating variables occurs only within single-quoted strings.
Responda
  • True
  • False

Questão 14

Questão
• PHP programs are executed on the client.
Responda
  • True
  • False

Questão 15

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

Questão 16

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

Questão 17

Questão
• The JDBC _____ libraries are called java.sql.*
Responda
  • Method
  • Function
  • Class

Questão 18

Questão
• What are the advantages and disadvantages of the embedded SQL approach.
Responda
  • 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.

Questão 19

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

Questão 20

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

Questão 21

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

Questão 22

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

Questão 23

Questão
• Discuss advantages and diadvantages to the library of function calls approach
Responda
  • 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.

Questão 24

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

Questão 25

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

Questão 26

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

Questão 27

Questão
• Describe the three main approaches for database programming.
Responda
  • • 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

Questão 28

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

Questão 29

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

Questão 30

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

Questão 31

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

Questão 32

Questão
• 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
Responda
  • True
  • False

Questão 33

Questão
• 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).
Responda
  • True
  • False

Questão 34

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

Questão 35

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

Questão 36

Questão
• How does a well-formed XML document look like?
Responda
  • • 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

Questão 37

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

Questão 38

Questão
• Three major differences between the relational and object database design.
Responda
  • • 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.

Questão 39

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

Questão 40

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

Questão 41

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

Questão 42

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

Questão 43

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

Questão 44

Questão
• The implementation of an operation is called its signature.
Responda
  • True
  • False

Questão 45

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

Questão 46

Questão
• 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.
Responda
  • True
  • False

Questão 47

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

Questão 48

Questão
• An object typically has three components: state, timing, and behavior
Responda
  • True
  • False

Questão 49

Questão
• 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.
Responda
  • True
  • False

Questão 50

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

Questão 51

Questão
• 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.
Responda
  • • Requirements analysis
  • • Feedback loops
  • • Feasibility analysis
  • • One-shot
  • • View integration

Questão 52

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

Questão 53

Questão
• 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.
Responda
  • True
  • False

Questão 54

Questão
• What are the three goals of database design?
Responda
  • 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.

Questão 55

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

Questão 56

Questão
• 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
Responda
  • True
  • False

Questão 57

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

Questão 58

Questão
• Identify the three factors to consider in choosing one DBMS over another
Responda
  • • 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

Questão 59

Questão
• _____ 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.
Responda
  • • Feasibility analysis
  • • Requirements collection and analysis
  • • View integration
  • • One-shot
  • • Feedback loops

Questão 60

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

Questão 61

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

Questão 62

Questão
• What two things does minimizing redundancy imply?
Responda
  • • 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

Questão 63

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

Questão 64

Questão
• 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.
Responda
  • True
  • False

Questão 65

Questão
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.
Responda
  • True
  • False

Questão 66

Questão
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
Responda
  • True
  • False

Questão 67

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

Questão 68

Questão
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
Responda
  • True
  • False

Questão 69

Questão
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).
Responda
  • True
  • False

Questão 70

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

Questão 71

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

Questão 72

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

Questão 73

Questão
A THETA JOIN uses the comparison operator =
Responda
  • True
  • False

Questão 74

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

Questão 75

Questão
A key uniquely identifies a tuple in a relation
Responda
  • True
  • False

Questão 76

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

Questão 77

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

Questão 78

Questão
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.
Responda
  • True
  • False

Questão 79

Questão
A relation schema may only have one key.
Responda
  • True
  • False

Questão 80

Questão
Tuples in a relation are ordered.
Responda
  • True
  • False

Questão 81

Questão
The DELETE operation can violate referential integrity.
Responda
  • True
  • False

Questão 82

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

Questão 83

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

Questão 84

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

Questão 85

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

Questão 86

Questão
Attributes must have unique domains.
Responda
  • True
  • False

Questão 87

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

Questão 88

Questão
All tuples in a relation must be distinct.
Responda
  • True
  • False

Questão 89

Questão
The $d->query function takes an SQL command as its string argument and sends it to the database server for execution.
Responda
  • True
  • False

Questão 90

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

Questão 91

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

Questão 92

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

Questão 93

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

Questão 94

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

Questão 95

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

Questão 96

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

Questão 97

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

Questão 98

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

Questão 99

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

Questão 100

Questão
Storing the same data multiple times
Responda
  • Redundancy
  • Data abstraction
  • Relationship
  • Virtual data

Questão 101

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

Questão 102

Questão
Choose correct answer

Questão 103

Questão
Choose correct answer!!

Questão 104

Questão
Choose one

Questão 105

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

Questão 106

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

Questão 107

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

Questão 108

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

Questão 109

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

Questão 110

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

Questão 111

Questão
= 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
Responda
  • • LEFT OUTER JOIN
  • • SELECT
  • • PROJECT
  • • JOIN
  • • INTERSECTION

Questão 112

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

Questão 113

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

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