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CUSTOMER_CODE
SMUDE
DIVISION_CODE
SMUDE
EVENT_CODE
APR2016
ASSESSMENT_CODE MCA3020_APR2016
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
18249
QUESTION_TEXT
Explain various architectural approaches of OODBMS?
SCHEME OF
EVALUATION
1.Distributed Client Server Approach:
Client processes manage application specific activities like utilization
and updation of separate objects. These processes may be situated on the
same workstation or on dissimilar workstations. Usually a single server
will communicate with numerous clients providing simultaneous
requests for data which is managed by that server. There are three
different work-station server architectures that have been proposed for
OODBMS. They are as follows:
a.Object ServerApproach: A object is considered as the unit of transfer
from server to client. Both machines store objects and are competent of
performing methods on objects. Object-level locking is carried out
easily. The main disadvantage of this approach is the overhead related
with the server interaction needed to access each object.
b.Page Server Approach: In this approach, we consider page as the unit
of transfer from server to client. The overhead of object access is
decreased by the transfers of page level since it does not need server
interaction at all times. You can simplify the architecture and
implementation of the server as it needs only executing the services of
backend databases.
c.File Server Approach: In this approach, the client processes of
OODMBS have an interaction with a network file service for reading
and writing database steps. This approach makes the process of the
server implementation simpler because there is no need to manage
secondary storage. The main disadvantage of this approach is that it
requires two network interactions for accessing data.(4 marks)
2.Data Access Mechanism: Assessment of Object Oriented DBMS
products take into account the procedure required to shift data from
secondary store unit into a consumer application. Usually this
necessitates interaction with the server process, probably across one
network. Objects are stored into a consumer’s memory may need more
processing. The cost and procedure of releasing locks, and updated
objects that are returned to the server should be considered. (2 marks)
3.Object Clustering: The process of transferring units larger as compared
to an object is done under the supposition that an access of an application
to a specified object specifies a high possibility that it may also access
other related objects. When transferring number of objects, further server
interaction may not be required to assure these further object accesses.
Object clustering can be defined as the capability for an application to
offer information to the object oriented DBMS. This is done so that
objects which are usually accessed mutually can be accumulated close to
each other and therefore benefits from bulk transfers of data.(2 marks)
4.Heterogeneous Operation: In this approach, an object oriented DBMS
offers a method in which application can work together. This is done by
sharing access to a common group of objects. Numerous concurrent
applications are supported by a usual OODBMS; these applications are
executed on numerous processors which are connected through a local
area network. Frequently, the processors will be from dissimilar
computer companies where each company comprises its own data
representation formats. To make applications work together in this kind
of environment, data must be converted to the representation format
appropriate for the processor. (2 marks)
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
18252
QUESTION_TEXT
Discuss Lorel Query Language. Differentiate between XML Oriented
Databases and Native XML Databases.
SCHEME OF
EVALUATION
Lorel Query Language:Lorel is considered as an early query language
used for semi structured data. Lorel language makes use of the OEM
(Object Exchange Model) as the data model for semi structured data.
Lorel is utilized to expandOQL (Object Query Language) for the
procedure of querying elements. This is done by depending on coercion
at various levels to hold back the powerful typing of OQL. Lorel is also
used to extend OQL with path expressions. This is done in order that
user can state the patterns that are corresponding to actual paths in
referred data.(4 marks)
One of the advantages of Lorel language is its easy syntax which makes
users to understand it more clearly. The drawback of Lorel language is
that it is dependent on OQL parser. Also it comprises of limited
functionalities. (2 marks)
Differences between XML Oriented Databases and Native XML
Databases: XML-oriented databases are typically relational and enclose
model or pattern driven extensions for transporting data to and from
XML documents and are usually intended for data-centric documents.
Following are the differences between XML Oriented Databases and
Native XML Databases:
1.A native XML database is used to maintain physical structure. An
XML-oriented database can do so also, but practice shows a diverse
story.
2.Native XML database can accumulate data without schema. We could
make use of techniques to recognize structure in unprocessed documents
to be accumulated in XML-oriented systems. These types of techniques
are relatively limited.
3.XPath, DOM, or comparable XML-associates APIs are required to
access data in native XML systems. Alternatively, XML-oriented
systems provide direct access to the data via open-standard APIs, like
open database connectivity (ODBC).
(4 marks)
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
18253
QUESTION_TEXT
Explain Temporal Database and Multimedia Database.
SCHEME OF
EVALUATION
Temporal Database: Temporal databases are used to record timereferenced data. Basically, majority of the database technologies are
temporal. For example: Record keeping function (inventory
administration, medical-record and personnel); Financial function
(banking, accounting and portfolio organization); Scientific function
(Weather monitoring), Scheduling function (project organization, hotel,
airline, and train reservations) all these functions trust on temporal
databases. (2 marks)
Temporal databases are best suited for the applications where
information as to organize on time constraints. Therefore temporal
database set a good example to demonstrate the requirement for
development of a combined set of concepts for the use of application
developers. The training of temporal database is designed by application
developers and designers. There are numerous applications where time is
an important factor in storing the information. For example: Insurance,
Healthcare, Reservation Systems, and Scientific Databases. (2 marks)
In case of temporal applications, even the two instances utilized might be
simply expanded. For example, in COMPANY database, it might be
desirable to keep PROJECT, JOB, and SALARY histories of all the
employees. It can be applied to UNIVERSITY database as well, to store
the grade history of STUDENT. The details about the YEAR,
SEMESTER, COURSE and each SECTION are also included in this
database.(1 mark)
Multimedia Database: Multimedia databases facilitate the users to store
as well as generate query for retrieving multimedia information. This
information can demand for: Documents (like articles/books/journals),
Images (like drawings/pictures), Video Clips (like
newsreels/movies/hone videos); Audio clips (like speeches/ phone
messages/ songs).(1 mark)
The primary type of database query generally tries to locate multimedia
sources comprising of particular objects of interest. Such as, one user
wants to locate all the video clips regarding aa specific person, say
Michael Jackson in a video database. Another scenario may be as of
someone willing to retrieve video clips grounded on specific activities
like, video clips where a soccer goal is scored by a certain player or
team. These type of queries are mentioned as content based retrieval, as
they retrieve information bases on a certain activity/object from the
multimedia sources.
(2 marks)
To make this retrieval fast, the multimedia database must make use of
some model to index and manage multimedia sources grounded on the
contents. But identifying the contents of multimedia sources is lengthy
and difficult task. To accomplish this task, two approaches can be
followed as defined below:
1.Based on automatic analysis of the multimedia sources. It is done to
recognize the contents mathematical characteristics.
2.Based on manual identification of the objects and objectives of interest
in each multimedia source. And later on depending on this information
index the sources.
(2 marks)
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
73631
QUESTION_TEXT
What is an adaptive system? What are the features that make the query
processing system to be adaptive? Discuss the applications of adaptive
query processing system.
SCHEME OF
EVALUATION
Definition – 2 marks 3 features – 3 marks 5 applications – 1 mark
each
Adaptive systems are systems that modify their behavior by the use of
introspection, learning etc. also known as self tuning or dynamic
systems.
Features – obtains information from its environment
• Applies this information to decide its behavior
• This process repeats again and again, resulting in a feedback loop
among environment and behavior
Applications:
• Adaptive query processing in data grids (used to offer better QoS to
users and applications in spite of dynamically changing resourecs and
environments)
• Adaptive query processing in internet applications (efficiently
dealing with transfer rates and unpredictable, dynamic data volumes by
making use of adaptive query processing techniques)
• Adaptive query processing in web based data integration
(Mediators for this application requires the capability to handle
multiple, often conflicting objectives such as cost, coverage and
execution flexibility. This requires the development of adaptive query
processing algorithms)
• Adaptive query processing in wide area database systems (it is
difficult to produce efficient database query plans depending upon
information available only at compile time in broad area db systems.
Solution is by adusting query plan to varying conditions during
execution as well as by making use of information that becomes
available at query run time)
• To detect and correct optimizer (Adaptive query processing is
utilized to detect and correct optimizer errors due to wrong statistics or
simplified cost metrics)
QUESTION_T
DESCRIPTIVE_QUESTION
YPE
QUESTION_ID 125267
QUESTION_T
State the differences between centralized and distributed database.
EXT
SCHEME OF
5 differences ->2 marks each. Any 5 advantages among those mentioned
EVALUATION below may be written
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
125271
QUESTION_TEXT
Differentiate between BCNF and 3 NF.
Comparison of BCNF and 3NF
We have seen BCNF and 3NF.
SCHEME OF
EVALUATION
It is always possible to obtain a 3NF design without sacrificing losslessjoin or dependency-preservation.
If we do not eliminate all transitive dependencies, we may need to use
null values to represent some of the meaningful relationships.
Repetition of information occurs.
These problems can be illustrated with Banker-schema.
As banker-name bname , we may want to express relationships
between a banker and his or her branch.
Figure : An instance of Banker-schema.
Figure shows how we must either have a corresponding value for
customer name, or include a null.
Repetition of information also occurs.
Every occurrence of the banker's name must be accompanied by the
branch name.
If we must choose between BCNF and dependency preservation, it is
generally better to opt for 3NF.
If we cannot check for dependency preservation efficiently, we either
pay a high price in system performance or risk the integrity of the data.
The limited amount of redundancy in 3NF is then a lesser evil.
To summarize, our goal for a relational database design is
BCNF.
Lossless-join.
Dependency-preservation.
If we cannot achieve this, we accept
3NF
Lossless-join.
Dependency-preservation.
A final point: there is a price to pay for decomposition. When we
decompose a relation, we have to use natural joins or Cartesian products
to put the pieces back together. This takes computational time.