ELK ASIA PACIFIC JOURNAL OF LIBRARY MANAGEMENT AND INFORMATION TECHNOLOGY. ISSN (Online): ; Volume 1 Issue 2 (2015)

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1 RELATIONAL DATABASE MANAGEMENT SYSTEMS AND QUERIES OF CONTAINMENT Shivam Nagpal Assistant professor Punjab Technical University Jalandhar, Punjab, India Reema Mahajan Assistant professor Punjab Technical University Jalandhar, Punjab, India ABSTRACT A virtually entire proposal for Extension Markup Language Querying involves a query class which is known as queries of containment. It is clear that in future a considerable number of extension markup language information will be stored in relational DB. This emerges the query of how to assist these queries of containment. The inverted list technique that underlies most of the retrieval of information is suited well to these queries but should the author execute this technique: 1) using query execution machinery and native tables of RDBMS? Or (2) in an isolated loosely coupled engine of IR. With choices (2) greater than 20 years of work on optimization query of relational database management system, scalability, control of concurrency, recovery and execution of query expand instantly to structures and queries that execute these new operations. But all this will be not relevant if the choice performance (2) lags that of (1) by too much. In this study the author describes certain applications of performance of both choices using native implementations in 2 commercial systems of relational database and in a special need inverted list engine. The analysis of the study further recognizes 2 essential causes that distinguish the performance of relational database management system and IR implementations namely the join algorithms engaged and the utilization of hardware cache. The results of the study recommend that contrast to several expectations with certain changes a native implementation in a relational database management system can assist this query class much more effectively. Keywords : relational database management systems, inverted index, mark up language, containment query. Introduction: Virtually in each language of query suggested for extensive markup language involving YATL, Lorel, Quilt, XQL, XML- QL and even much generic SGML languages of query and queries of containment plays an essential role. By queries of containment the author refers queries that are based on proximity and containment rapport among attributes, contents and elements. When there is a big deal of work being performed on how to assist such languages of query in special purpose engines of query, it is evident that a big deal of extensive markup language data will be stored in RDB in foreseeable future. Since queries of containment are an essential querying extensive markup language data aspect and relational database management systems must assist the querying and storage of extensive markup language data. 1

2 The inverted list technique that underlies most of the retrieval of information is suited well to queries of containment but the author must execute this technique (1) using the query machinery and native tables of relational database management systems? Or (2) in a loosely coupled engine of IR. Commercial products namely DB2 Text extenders and Oracle InterMedia Text adopt choice (2) where a special purpose engine of IR is coupled with the engine of database. The results of query from both the engines are then integrated before returning to user. In this kind of system a glue module must be utilized between the major database and IR engine to manage concurrency control, locking and recovery. The (2) choice uses the processing power and database storage to process the queries of containment. Greater than 20 years of performance on optimization of query, scalability, execution of query, recovery and concurrency control instantly expand to structures and queries that execute new operations. Additionally this approach has the benefit of one unified execution and optimization structure for entire queries. In this study the author acquires a first step in describing the two choices. The author contrasts the containment queries implementation utilizing native assistance in two commercial RDB systems and in a special motive engine of inverted list. The author transform inverted index into tables of relation and convert queries of containment into queries of structured query language. It turns out that a native execution using a relational database management systems can operate queries that are either impossible or difficult to perform by an engine of inverted list. This study s performance reveals that while relational database management systems are suited badly for queries of containment under some conditions they can perform better than the engine of inverted list. Also the experiments of the study to two essential causes that distinguish the relational database management stems and IR [performance implementations: 1) the cache of hardware utilization accomplished; and 2) the join algorithm engaged. The engine of inverted list utilizes a merge join which is known as MPMGJN (Multi Predicate Merge Join) as its join operator of workhouse. To separate the differences of algorithm from other factors this study executes the index nested loop join and standard merge join themselves. Additionally with leading sizes of memory getting bigger and the hierarchy of memory 2

3 getting deeper several researchers have identified the significance of case use on performance. Processing of containment query: The queries of containment are a group of queries based on relationships of containment among contents, elements and their attributes. This class includes path expressions of database and proximity queries and information retrieval Boolean. Since queries of complex containment can be decreased to a sequence of several general ones and basic queries of containment shed much light on the basic performance determinants this study focus mainly on easy queries of containment such as title consisting of galaxy. Queries of containment: The path expressions descriptions can be predicted in Quilt and LoreL. The path expressions of Quilt are based on abbreviated XPath syntax. Since Quilt is the first Extensive Markup Query language that fulfills the W3C Extensive Markup Language Query needs and XPath became a suggestions of W3C in 1999 Novemeber the path expressions of Quilt style is probable to be used widely. Thus this study acquires their syntax to explain the queries of containment. Processing of Containment Query using Inverted Index: The inverted index is familiar in systems of information retrieval as it assists proximity, ranking queries and Boolean effectively. The classic data structure of inverted index represents a word text to a list which compute documents consisting of word and its place within every document. In order to perform structured documents such as Extensive Markup Language the inverted index can be expanded in a simple way. Every inverted list registers the word existences or an element. Every existence is indexed by its number of document, its nesting depth and its position within the document. If the document is in a format of parsed tree the position can be produced by performing a depth first tree traversal and allotting a number at every visit sequentially. Since every node of non-leaf is traversed twice often once before visiting entire children and once after it has 2 numbers allotted while nodes of leaf have only a single number. A structure utilizing inverted lists to perform queries of containment can be built using these 3

4 operations as general blocks of building and this study have executed a system of prototype. Processing of containment query using relational database management system: This study executes the relational schema utilized to store inverted index and representation from queries of containment to structured query language queries and then the author describes two extra kinds of queries that can be executed as an outcome of using an extensible and strong relational database management system. By executing the queries of containment using relational database management systems the author is capable to perform queries that are impossible or difficult to perform using an engine of inverted list. Analysis and Performance: The author carries out the performance study contrasting the containment queries implementation in a relational database system and in a special purpose engine of inverted list. The aim of this study is to describe the differences of performance, seek reasons for the variations and offer insights into weaknesses and strengths of relational database management system on queries of containment. Three sets of extensive markup language data were utilized in the study. The first was the plays of Shakespeare the second was a group of DBLP files of bibliography and the third was a group of synthetic extensive markup language documents. In the set of synthetic data the number of existences of text words followed the distribution of Zipflan with constant and the number of existences of elements followed the distribution of Zipflan with 1.5 constant. In the implementation of relational database management systems with indexes constructed on tables the term rows can be retrieved selectively thus saving both central processing unit and input/output time. The queries for which database carries out better have a similar feature one term in query is highly preferred while the other term is not preferred. The savings on input/output and central processing unit must be big enough to compensate for overheads incurred by relational database management system. When the relational database management system out performs the engine of inverted list will not be rare. It will emerge whenever one predicate in a query is preferred highly. Utilization of hardware cache: 4

5 With major sizes of memory getting bigger and the hierarchy of memory getting deeper several researchers have identified the impact of better utilization of hardware cache on performance. This study organized experiments to view whether there occurs essential difference between relational database management system and inverted list engine on queries of containment. This group of experiments were organize on a machine with 800 megahertz Intel P3 processing performing a v Linux Kernel. The instruction and the data accesses to second level cache can be estimated separately. The P3 processor assists execution out of order and prefetching instruction. The latter denotes that fetches of data/instruction can be overlapped. Related Work: A considerable number of work has been performed on combining information retrieval particularly text searching with systems of database. The invention of Standard Generalized Markup Language has triggered most of the study on combining structure and content in retrieval of text. This study work does not concentrate on growth of containment algorithms rather it concentrates on how to execute the algorithms in a relational database management system. There is also work that regards using relational database management system to retrieve and store extensive markup language documents. These studies concentrate on technologies for converting extensive markup language documents from and to relations and are complementary to this study which concentrates on performance of implementation choices for a query class over extensive markup language data. Putz explains using a RDBS for retrieval of information. Florescu et al utilizes a varied schema to store inverted index where every varied extensive markup language text word and element postings is stored in its own table. Conclusion: The queries of containment will be an essential number of workloads of extensive markup language query. In foreseeable future a big deal of extensive markup language data will be stored in relational systems. Presently in commercial world the approach in which an IR indexing system is glued to a relational system influence. However the author have discussed in 5

6 introduction there are compelling issues to regard a much tightly coupled approach in which queries including containment are assisted by native relational database management system structures of data, query processors and optimization of query. This tightly coupled approach will not be essential unless its performance is fulfilled. There exists to be no individual factor that reports for complete performance variation between two kinds of systems and changing relational database management system so that its performance matches that of special purpose engine of inverted list will be nontrivial. The addition of new join algorithm will be an essential number of successful effort to make relational database management system rivalry with a special purpose engine of IR on extensive markup language queries of containment. The ongoing study on cache aware database and main memory systems is probable to generate a new generation of relational database management systems that have good utilization of cache. While it is premature to make concrete predictions the authors are optimistic that by integrating better join algorithms with good cache utilization relational database management system will be capable to assist queries of containment effectively. References: [1] Ailamaki, D.J.DeWitt, M.D.Hill, and D.A.Wood. Dbmss on a modern processor: Where does time go? In Proceedings of the 25th International Conference on Very Large Data Bases, pages 266{277, September [2] Shatdal, C. Kant, and J.F.Naughton. Cache conscious algorithms for relational query processing. In Proceedings of the 20th VLDB Conference, [3] Alin Deutsch, Mary Fernandez, Daniela Florescu, Alon Levy, and Dan Suciu. A query language for xml. In Proceedings of Eighth International World Wide Web Conference, [4] L. Clarke, G. V. Cormack, and F. J. Burkowski. An algebra for structured text search and a framework for its implementation. The Computer Journal, 38(1):43{56, [5] C.L.Clarke, G.V.Cormack, and F.J.Burkowski. Schema-independent retrieval from heterogeneous structured text. In Fourth Annual Symposium on Document Analysis and Information Retrieval, pages 279{289, [6] Daniela Florescu and Donald Kossman. Storing and querying xml data using an rdbms. IEEE Data Engineering Bulletin, 22(3):27{34, [7] Daniela Florescu, Donald Kossmann, and Ioana Manolescu. Integrating keyword search into xml query 6

7 processing. WWW9/Computer Networks, 33(1-6):119{135, [8] Don Chamberlin, Peter Frankhauser, Massimo Marchiori, and Jonathan Robie. Xml query [9] G. E. Blake, M. P. Consens, P. Kilpelainen, P.-A. Larson, T. Snider, and F. W. Tompa. Text/relational database management systems: Harmonizing sql and sgml. In Proceedings of the International Conference on Applications of Databases, pages 267{280, June DOI: / _54 [10] G. Salton and M.J. McGill. Introduction to Modern Information Retrieval. McGraw-Hill, New York, [11] G.K. Zipf. Human Behavior and the Principle of Least E ort. Addison-Wesley, Reading MA, [12] Intel. Intel architecture software developer's manual, volume 1: Basic architecture, [13] International Organization for Standardization.Information processing {text and office systems {standard generalised markup language (sgml), iso/iec 8879, [14] J.McHugh, J.Widom, S.Abiteboul, Q.Luo, and A.Rajaraman. Indexing semistructured data. In Stanford Technical Report, January [15] J.McHugh, S.Abiteboul, R.Goldman, D.Quass, and J.Widom. Lore: A database management system for semistructured data. SIGMOD Record, 26(3):54{66, [16] Jayavel Shanmugasundaram, E. Shekita, R.Barr, Michael J. Carey, Bruce G. Lindsay, Hamid Pirahesh, and Berthold Reinwald. Efficiently publishing relational data as xml documents. In VLDB Conference, September [17] Jayavel Shanmugasundaram, He Gang, Kristin Tufte, Chun Zhang, David DeWitt, and Je rey Naughton. Relational databases for querying xml documents: Limitations and opportunities. In Proceedings of the 1999 VLDB Conference, September [18] Jun Rao and Kenneth A. Ross. Making b+-trees cache conscious in main memory. In SIGMOD Conference, pages 475{486, [19] Ricardo Baeza-Yates and Gonzalo Navarro. Integrating contents and structure in text retrieval. SIGMOD Record, 25(1):67{69, March [20] Ron Sacks-Davis, Timothy Arnold- Moore, and Justin Zobel. Database systems for structured documents. In Proceedings of the International Symposium on Advanced Database Technologies and Their Integration (ADTI'94), pages 272{283, October [21] Roy Goldman and Jennifer Widom. Wsq/dsq: A practical approach for combined querying of databases and the web. In Proceedings of the 2000 Sigmod Conference, pages 285{296, [22] S. Abiteboul, D. Quass, J. McHuge, J. Widom, and J. Wiener. The lorel query language for semistructured data. 7

8 International Journal on Digital Libraries, 1(1):68{88, April [23] S.Cluet, S.Jacqmin, and J.Simeon. The new yatl: Design and specifications. In Technical Report, INRIA, [24] Sleepycat Software. The berkeley database. [25] Stefan Dessloch and Nelson Mattos. Integrating sql databases with contentspecic search engines. In Proceedings of the 23rd VLDB Conference, [26] Steve Putz. Using a relational database for an inverted text index. In Xerox Palo Alto Research Center Technical Report SSL-91-20, Xerox PARC, January [27] T.Arnold-Moore, M.Fuller, B.Lowe, J.Thom, and R.Wilkinson. The elf data model and sgql query language for structured document databases. In Proceedings of the Australasian Database Conference, Adelaide, Australia, pages 17(26), [28] Tak W. Yan and Jurgen Annevelink. Integrating a structured-text retrieval system with an [29] Tuong Dao, Ron Sacks-Davis, and James A. Thom. Indexing structured text for queries on containment relationships. In Proceedings of the 7th AustralasianDatabase Conference,