Database Systems Engineer Examination.pdf

Database Systems Engineer Examination

October, 2005 VITEC

Database Systems Engineer Examination (Morning)

1 Examination Time-9:00-10:30 (90 minutes)

2 Questions must be answered in accordance with the following: Question Nos Q1-Q50

Question Selection All questions are compulsory

3 Mark your examinee information and test answers in accordance with the instructions below (1) Use an HB black pencil If you need to change an answer, fully erase the undesired mark with a rubber eraser until no mark remains Remove rubber bits on the paper

(2) Answer sheets are processed through an optical reader Mark your answers according to the answer sheet marking method given in (5) below

(3) Fill in and mark the test number in the test number area If an answer is not marked correctly, or is marked differently than explained in (5), your test cannot be scored

(4) In the Date of Birth area, fill in your Date of Birth exactly as printed on your test form If this item is not marked correctly, your test cannot be scored

(5) Mark only one answer for each question, as shown in the example below

Example: In what month is the Spring Information Processing Engineer Exam held?

Since the correct answer is “c” (April), mark your answer sheet as follows:

4 After you complete and turn in your exam, you can take this question booklet home with you

Do not open the exam booklet until instructed to do so Inquiries about the exam questions will not be answered

Company names and product names appearing in the test questions are trademarks or registered trademarks of their respective companies Note that the ® and ™ symbols are not used within

Q1

Which system attempts to speed up data transfer to an auxiliary storage device equipped with the channel control system of a general-purpose computer, by continually sending data without waiting for a confirmation signal?

a) Serial system b) Streaming system c) Parallel system d) Handshake system

Q2

Which of the following is a von Neumann bottleneck (a factor that prevents performance improvement with a computer that sequentially fetches and executes program instructions in the CPU)?

a) Main memory capacity

b) Data transfer capacity between an internal device (processor and main memory) and an I/O device

c) Data transfer capacity between a processor and the main memory d) Processor performance

Q3

Which of the following is a correct statement concerning virtual storage systems?

a) An LRU algorithm is a page-replacing algorithm that replaces the page for which the the longest time has elapsed since it was last used

b) To convert an address by indexing requires a page table of all pages in the main memory

c) When a page fault occurs, garbage collection is required

d) Fragmentation occurs when many small areas of available memory are created during repeated paging

Q4

Which of the following is a correct statement concerning OS scheduling methods?

a) In the processing time-sequenced method, higher priority is given to the job that has already consumed a larger amount of CPU time

b) Response time, for jobs requiring particularly short processing time, is much shorter in the arrival-sequenced method in comparison with the round robin method c) In the priority-sequenced method, the response time of some jobs can be extremely

long

d) The shorter the CPU time (time quantum) allocated to a job in the round robin method, the closer the method is to the arrival-sequenced method

c) In the preemptive system, certain processes monopolize the processor more frequently than in the non-preemptive system

d) Realizing a preemptive system requires a mechanism whereby the OS can forcefully switch and execute processes

Q6

Which of the following systems offers the best results in introducing a three-tier client-server architecture?

a) A system with a small number of application services and classes b) A system where correction and addition of applications are frequent c) A system in which all applications are written in the same language d) A system with a comparatively small number of transactions

Q7

A device provides services at a rate of 5 sec per transaction on the average What is the least number of devices needed to bring device usage rate below 0.5 sec, even when the average arrival is 20 transactions per minute?

Q8

A system sends data from a server to a magnetic disk device over a LAN at a data transfer rate of 10 Mbps The table below gives the measured transfer speed of the server and the measured reception speed of the client for differing numbers of clients to which the server simultaneously sends data From these results, it can be seen that server transfer speed does not increase over 300 Kbps when there are 2 or more clients Which of the following is the most likely cause of this? In all of these measurements, the server and all of the clients have sufficient CPU performance and memory capacity

Data transfer rate (Kbps)

a) Insufficient data transfer capacity of the LAN itself

b) Insufficient capacity of the client’s LAN connection interface mechanism c) Insufficient capacity of the client’s magnetic disk device

d) Insufficient capacity of the server’s LAN connection interface mechanism

Q9

If the performance of a single CPU is 1, then the performance P of a multiprocessor containing

n these CPUs is expressed as:

In this formula, a is a constant which expresses the overhead For example, if a = 0.1 and n = 4, then P 3, so the performance of a multiprocessor consisting of 4 CPUs is approximately 3 The multiprocessor performance expressed in this equation has an upper limit It will not

increase beyond a certain value no matter how large a number n may be What is this value if a

= 0.1?

Q10

Which of the following correctly expresses the MTBF and MTTR of the system in the work

model diagram below? Here, ti is the system running time and ri is the system repair time (i = 1,

Which of the following statements correctly describes a technology used to increase the reliability of a computer system?

a) “Failsafe” is a technology that reduces failure by increasing the reliability of individual components

b) “Failsoft” is a technology for handling system faults caused by software

c) “Fault avoidance” is a technology that enables operations to continue even if a failure occurs in a component

d) “Fault tolerance” is a technology, whereby critical parts which form a system are installed redundantly, to cope with the occurrences of failures

Q12

Running Running Running

Failure Failure Failure

Repair Repair Repair

Running

Which of the following statements correctly describes data mining?

a) Its primary objective is the analysis of time-series data which do not involve update processes, created separately from the core operations database

b) It analyzes customized data that are extracted according to the analyzer’s objectives, such as personal data, departmental data, and summary data

c) It performs multidimensional analysis through interactive operations such as slicing, dicing, and drilling down in order to support decision-making

d) It creates theories, such as customer purchasing behaviors, from large amounts of stored data using neural networks, statistical analysis, and other techniques

Q13

Which of the following is the correct expression of the recall ratio and precision ratio used as measures in evaluating information retrieval systems, such as document retrieval systems and data retrieval systems? Here, A, B and C indicate the following

A: The number of data cases amongst all accumulated data that are suitable to the inquiry B: The number of data cases amongst retrieved data that are suitable to the inquiry C: The number of data cases retrieved

Recall ratio Precision ratio

b) It has an IF-THEN format to express conditions and behavior c) Its format comes from a correspondence list of slot-to-slot values d) Its format consists of proposition logic and predicate logic

Q15

Which of the following correctly defines a repository in software development?

a) It is a database of software components provided to support development

b) It is a database that centrally manages design information and program information in software development and maintenance

c) It is a database for storing software development tools and data models

d) It is a database for storing source program analysis software and analysis results for reverse engineering

Q16

Which of the following is a correct statement in regard to prototyping?

a) It is more suitable for batch systems than GUI-based interactive systems b) Effectiveness can be increased by repeatedly remaking the prototype

c) It assumes there are frequent requirement specification changes, so it cannot be used in the waterfall model

d) It is not suited for the development of systems with a long life cycle or for packages to be used by many people

Q17

Which of the following is a correct statement concerning inheritance in object orientation? a) When a subclass is defined under a given class, the data structures and procedures

defined in the higher class can be inherited and used in the subclass

b) Data structures and values determining an object’s characteristics are hidden and direct access from outside the object is prohibited

c) Even if an object’s data structure or processing method is changed, impact to the outside can be avoided, allowing the object’s independence to be improved

d) It expresses objects having identical data structures and identical procedures all together

Q18

Which of the following is a correct statement in regard to black box tests?

a) Test case coverage is used as a criterion for creating test data

b) Even if the tested program contains redundant code, it cannot be detected

c) A black box test focuses on a program’s internal structure and verifies whether the required parts have been executed

d) Test data increases significantly as the numbers of branch instructions and modules increase

Q19

There is a database in which data additions, changes, and deletions occur at a certain low frequency The interval between backups has been increased to twice the current level for backing the database onto magnetic tape Which of the following is a correct statement with respect to the database operations?

a) The average recovery time from journal information will increase by a factor of approximately 2

b) The database capacity will increase by a factor of approximately 2

c) The number of magnetic tapes required for a single backup will decrease by approximately one-half

d) The average backup execution time will increase by a factor of approximately 2

Q20

Which of the following correctly describes an ANSI/SPARC schema of a three-layer structure that defines all of the real world data required in data processing and a data structure that does not depend on a special application program?

a) Conceptual schema b) External schema

Q21

Which of the following statements correctly describes a conceptual data model?

a) It includes a hierarchical model, network model and relational model b) It abstractly expresses a job process

c) Its content differs depending on whether a centralized DBMS is introduced or a distributed DBMS is introduced

d) It expresses information requirements of the target world

Q22

When comparing a relational database with an object-oriented database, which of the following statements correctly describes the object-oriented database?

a) It can express real world information as a modelled class hierarchy and, by using this class hierarchy, it can separately handle data and operations

b) It encapsulates data and procedures, and handles them as a single unit, therefore it can handle complicated objects that contain operations

c) Data manipulation and relations are mathematically defined, therefore it is independent of programming languages and data manipulation languages

d) It defines relations by logical data structure, therefore it can perform data operations using non-procedural manipulation language

Q23

Which of the following is the correct combination of terms to insert in the blanks

A through C in the following statement describing the features of logical data models?

The hierarchical model and the network model express the relationship between entities as combinations of parent-child relationships In the hierarchical model, a single child has A , while in a network model, a single child has B On the other hand, a relational model is based on a mathematical set concept; the relation between one row in a table and a row in another table is done using C

A B C a) always one parent multiple parents the same value

b) always one parent multiple parents a pointer c) multiple parents always one parent the same value d) multiple parents always two parents a pointer

Q24

Which of the following expresses the breakdown of table X into a Boyce/Codd normalization?

Here, x → y means y is functionally dependent on x

X Functional dependencies existing in table X

Which of the following is a correct statement with respect to functional dependency? Here, A, B and C are groups of attributes of a particular relation

a) If B functionally depends on A and C functionally depends on A, then C functionally depends on B

b) If B is a subset of A and C functionally depends on A, then C functionally depends on B

c) If B is a subset of A , then A functionally depends on B

d) If the sum of B and C functionally depends on A, then each of B and C functionally depends on A

Q26

Which of the following is the correct combination of 1st, 2nd and 3rd normal forms, and their features A, B and C?

A: All non-key attributes entirely depend on the primary key B: No non-key attributes are transitionally functionally dependent C: There is no repetition of attribute values

1st normal form 2nd normal form 3rd normal form

a) To the 2nd b) To the 3rd c) To the 4th d) Not

Q28

How many different projections are there of a relation which has n attributes? Here, the number

of projections includes those with the same result as the original relation as well as those that do not have any attributes

Q29

Job rules are given as follows A data model was created on the basis of these rules Which one is the correct data model? Here, 1 * represents the cardinality of one to many

(Job rules)

This company sells diverse language educational materials such as textbooks, dictionaries, etc Sales persons are assigned multiple sales areas, and take orders from customers in the assigned areas Multiple sales persons are in charge of a single sales area

A conceptual data model of an organizational hierarchy of multiple divisions, departments, sections and groups was constructed as a 3rd normal form table:

organization (organization_ID, organization_name )

Which condition completes the blank below as the SQL statement that expresses the parent-child relations of the organization? Here, the underlined part of the “organization” description represents the primary key and it is necessary to assume additional attributes The “*” of multiplicity in the conceptual model represents 0 or greater, whereas 1 is assumed where no mark is given The role is written on the target side of the association line {Hierarchy} is a restriction notation that indicates that the organization hierarchy neither loops nor forms a