6

Question 1

The PEAR DB functions can be accessed using DB::<function_name>.

Answer

true

Question 2

The string argument of the function for connecting to a database is of the format ://:@

Answer

true

Question 3

The PEAR DB functon for connecting to a database is called DB::linkto database('string').

Answer

true

Question 4

The DBMS software in ://:@ 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

Question 5

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

Answer

true

Question 6

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.

Accepted Answer

Associative

Answer

Numeric

Answer

Value

Answer

String

Question 7

Multi-line PHP comments start with // and end with #.

Answer

true

Question 8

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

Question 9

The PHP start tag is <?php and end the tag is ?>.

Answer

true

Question 10

Web pages, where part of the information is extracted from databases or other data source, are called dynamic Web pages

Answer

true

Question 11

In PHP, a ____ array associates a numeric index with each element in the array

Accepted Answer

Numeric

Answer

Assosiative

Answer

Variable

Answer

String

Question 12

PHP variable names start with a $ sign and can include characters, numbers, and the underscore character

Answer

true

Question 13

Interpolating variables occurs only within single-quoted strings.

Answer

true

Question 14

PHP programs are executed on the client.

Answer

true

Question 15

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

Answer

true

Question 16

The JDBC _____ libraries are called java.sql.*

Accepted Answer

Class

Answer

Method

Answer

Function

Question 17

JDBC does not distinguish between queries that return single tuples and those that return multiple tuples.

Answer

true

Question 18

What are the advantages and disadvantages of the embedded SQL approach.

Accepted 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.

Accepted Answer

Disadvantage are the loss of flexibility in changing the query the query at runtime and that all changes to queries must be recompiled.

Answer

The main advantage is flexibility in generating queries at runtime. Also, the library of function calls approach is able to call multiple data program.

Answer

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.

Answer

Disadvantage are more complex programming, inability to do checking at compile time, and concerns about SQL runtime errors.

Question 19

The use of function calls is a more dynamic approach for database programming than embedded SQL.

Answer

true

Question 20

A _____ object is similar to a cursor in embedded SQL and an iterator in SQLJ.

Accepted Answer

Result Set

Answer

Procedure

Answer

Function call

Question 21

_____ is the part of the SQL standard that specifies how to write persistent stored modules.

Accepted Answer

SQL/PSM

Answer

XML

Answer

SQLJ

Answer

ResultSet

Question 22

Database stored procedures (aka persistent stored modules) are stored and executed by the DBMS at the database server.

Answer

true

Question 23

Discuss advantages and diadvantages to the library of function calls approach

Accepted Answer

The main advantage is flexibility in generating queries at runtime. Also, the library of function calls approach is able to call multiple data program.

Accepted Answer

Disadvantages are more complex programming, inability to do checking at compile time, and concerns about SQL runtime errors.

Answer

Disadvantage are the loss of flexibility in changing the query at runtime and that all changes to queries must be recompiled.

Answer

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.

Answer

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

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

Question 25

In SQLJ, embedded SQL commands are preceded by #sql.

Answer

true

Question 26

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

Answer

true

Question 27

In XML _____ defines the set of commands (names) that can be used

Accepted Answer

Namespace

Answer

Valid

Answer

Document

Answer

Invalid

Question 28

Describe the three main approaches for database programming.

Accepted 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.

Accepted Answer

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.

Accepted Answer

Designing a new database programming language.

Answer

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

Answer

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.

Answer

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 29

In XML schema, the tag _____ is used to specify primary keys.

Accepted Answer

xsd:key

Answer

xs:element

Answer

psd:schema

Answer

xs:sequence

Question 30

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

Answer

true

Question 31

If an XML document is well-formed and follows a particular schema, it is _____

Accepted Answer

Valid

Answer

Namespace

Answer

Keys

Answer

Invalid

Question 32

The XML schema, it is possible to specify constraints that correspond to unique and primary key constraints in a relational database, as well as foreign keys constraints

Answer

true

Question 33

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, non-repeating element).

Answer

true

Question 34

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

Question 35

The basic object in XML is the XML document, which is structured using types and iterators.

Answer

true

Question 36

How does a well-formed XML document look like?

Accepted Answer

It must finish with an XML declaration to indicate the version of XML.

Accepted Answer

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

Accepted Answer

It must start with an XML declaration to indicate the version of XML

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

Answer

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

Question 37

Struct type constructors include the set (T), list (T), bag(T), array(T), and dictionary (K,T) type constructors.

Answer

true

Question 38

Three major differences between the relational and object database design.

Accepted 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.

Accepted Answer

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

Accepted Answer

In ODB inheritance is built into the model; RDBs do not have built-in constructs for inheritance.

Answer

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

Answer

In RDB inheritance is built into the model; ODBs do not have built-in constructs for inheritance.

Answer

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

Question 39

The typical mechanisms for making an object an object persistent are naming and reachability.

Answer

true

Question 40

The main property required of an OID is that it be immutable (should not change).

Answer

true

Question 41

_____ inheritance occurs when a subtype inherits only some of the functions of a supertype.

Accepted Answer

Selective

Answer

Generalization

Answer

Complete incapsulation

Answer

Conditional

Question 42

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

Question 43

In ______ all operations that can be applied to an object must be predefined.

Accepted Answer

Complete incapsulation

Answer

Half encapsulation

Answer

Object identifier

Answer

Feedback loop

Question 44

The implementation of an operation is called its signature.

Answer

true

Question 45

A subtype is used when a new type is needed that is similar but not identical to an already defined type.

Answer

true

Question 46

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

Question 47

An ODMS provides a unique identity to each independent object in the database via a unique, system-generated ____.

Accepted Answer

Object identifier (OID)

Answer

Literals

Answer

Indirect pointer

Answer

Constructor

Question 48

An object typically has three components: state, timing, and behavior

Answer

true

Question 49

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

Question 50

The phases (or activities) of the life cycle are not strictly in sequence; ______ are common among and within the phases of the life cycle.

Accepted Answer

Feedback loop

Answer

One-shot

Answer

Requirements collection

Answer

View integration

Question 51

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 conceptual schema.

Accepted Answer

View integration

Answer

Requirements analysis

Answer

Feedback loops

Answer

Feasibility analysis

Answer

One-shot

Question 52

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

Answer

true

Question 53

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

Question 54

What are the three goals of database design?

Accepted Answer

Satisfy the information content requirements of the generalised users and applications.

Accepted Answer

Support processing requirements and any performance objectives.

Accepted Answer

Provide a natural and easy-to-understand structuring of the information.

Answer

Support result

Answer

Satisfy the information content requirements ofthe specified users and applications.

Answer

Provide a comlicated structuring of the information.

Question 55

_______ involves interacting with potential users and user groups to identify their particular problems and needs.

Accepted Answer

requirements collection and analysis

Answer

view-integration

Answer

feasibility analysis

Answer

one-shot

Answer

feedback loop

Question 56

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

Question 57

Identify the three criteria to guide the choice of physical database design options

Accepted Answer

Space utisilation

Accepted Answer

Transaction throughput

Accepted Answer

Response time

Answer

Availability of vendor services

Answer

Familiarity of personnel with the system

Question 58

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

Accepted Answer

Organization-wide adoption of a certain philosophy (data model, vendor, methodology, tools)

Accepted Answer

Availability of vendor services

Accepted Answer

Familiarity of personnel with the system

Answer

Space utilization

Answer

Transaction throughput

Answer

Response time

Question 59

_____ 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.

Accepted Answer

Feasibility analysis

Answer

Requirements collection and analysis

Answer

View integration

Answer

One-shot

Answer

Feedback loops

Question 60

The initial requirements can be expected to be formal, complete, consistent, and correct.

Answer

true

Question 61

In the ______ schema design approach, the requirements from the different stakeholders are merged into a single set of requirements before the schema design begins

Accepted Answer

Centralized (or one-shot)

Answer

Requirements collection

Answer

Feedback loop

Answer

Requirements analysis

Question 62

What two things does minimizing redundancy imply?

Accepted Answer

Reducing the need for multiple updates to maintain consistency across multiple copies of the same information.

Accepted Answer

Minimizing redundant storage of the same information

Answer

Reducing the redundant information in tuples.

Answer

Making sure the semantics of the attributes is clear in the schema

Answer

Disallowing the possibility of generating spurious tuples

Question 63

Third normal form (3NF): R is 2NF and all non-prime attributes are transitively dependent on the primary key.

Answer

true

Question 64

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

Answer

true

6

Crea una cuenta gratis para terminar este test

Preguntas del test (97)

Información

Escríbenos

¿Qué te parece el nuevo diseño?