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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.