• Proceedings of the Korean Information Science Society Conference
• /
• 2002.10c
• /
• pp.82-84
• /
• 2002

XML은 자기 서술적인 표현 언어라는 중요한 장점을 가지고 있기 때문에 인터넷 관련 응용들에서 정보의 표현 및 문서 교환의 표준으로 빠른 속도로 자리잡아 가고 있다. 본 논문에서는 SQL에 XPath 표현 중 일부를 추가하여 SQL을 확장함으로써 XML 문서에 대한 질의를 가능하게 하였고, 또한 SQL의 CRUD(Create, Read. Update, Delete) 기능을 그대로 사용함으로써 XML 문서의 변경이 가능한 XML 질의를 위한 새롭게 확장된 SQL을 제안하였다. 그리고 폭 넓게 사용되고 있는 ORDBMS 환경에서 XML 색인 정보를 자동 생성 관리하는 XML 저장 관리기 및 확장된 SQL 처리기를 설계하고 구현하였다. 본 논문에서 제안하는 확장된 SQL 처리기는 XML 원문 자체의 보관을 원칙으로 하여 완벽한 문서 복구 등에 따르는 부담을 제거하였고, XML 저장 문서에 대한 원본성 및 무결성을 쉽게 유지할 수 있도록 하였으며, 색인 정보를 자동 생성 관리함으로써 파일 처리 시간과 XML 트리 운행 시간 및 XPath 파싱 처리 시간을 줄였다. 또한, “path”라는 키워드를 추가로 관리함으로써 ORDBMS 환경에서 XML 질의를 위한 SQL 변환 과정에서 PATH의 깊이 만큼 조인이 중첩되는 문제를 배제하여 조인이 발생할 가능성을 줄이는 방법을 제시하였다.

• Digital Contents
• /
• no.10 s.53
• /
• pp.46-49
• /
• 1997

국내 OODBMS 및 ORDBMS 제품들이 해외 유명 제품들과 경쟁할 수 있는 방안이 무엇인가. 지난 7여년간 OODBMS 개발 프로젝트를 수행한 결과로 개발된 오디세우스 객체지향 멀티미디어 DBMS의 사례를 예시함으로써 국내에서 OODBMS 또는 ORDBMS를 개발하고자 하는 모든사람들에게 조금이라도 도움이 되었으면 한다.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.8 no.1
• /
• pp.63-74
• /
• 2005

The telematics device, which is a typical embedded system on the transportation or vehicle, requires the embedded spatial DBMS based on RTOS (Real Time Operating System) for processing the huge spatial data in real time. This spatial DBMS can be developed very easily by SQL3 functions of the ORDBMS such as UDT (user-defined type) and UDF (user-defined function). However, developing index suitable for the embedded spatial DBMS is very difficult. This is due to the fact that there is no built-in SQL3 functions to construct spatial indexes. In this study, we compare and analyze both Generalized Search Tree and Relational Indexing methods which are suggested as common ways of developing User-Defined Indexes nowadays. Two implementations of R-Tree based on each method were done and region query performance test results were evaluated for suggesting a suitable indexing method of an embedded spatial DBMS, especially for telematics devices.

• Journal of KIISE:Computing Practices and Letters
• /
• v.11 no.3
• /
• pp.209-215
• /
• 2005

Conventional ORDBMS vendors provide extension mechanisms for adding user-defined types and functions to their own DBMSs. Here, the extension mechanisms are implemented using a high-level interface. We call this technique loose-coupling. The advantage of loose-coupling is that it is easy to implement. However, it is not preferable for implementing new data types and operations in large databases when high Performance is required. In this paper, we propose to use the notion of tight-coupling to satisfy this requirement. In tight-coupling, new data types and operations are integrated into the core of the DBMS engine. Thus, they are supported in a consistent manner with high performance. This tight-coupling architecture is being used to incorporate information retrieval(IR) features and spatial database features into the Odysseus/IR ORDBMS that has been under development at KAIST/AITrc. In this paper, we introduce Odysseus/IR and explain its tightly-coupled IR features (U.S. patented). We then demonstrate a web search engine that is capable of managing 20 million web pages in a non-parallel configuration using Odysseus/IR.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.6 no.4
• /
• pp.37-50
• /
• 2003

In the paper, we describe the query extension techniques for spatiotemporal query functionalities on object-relational DBMS. The spatial objects in real world change the shapes over time. Spatiotemporal databases support to manage a temporal dimension as well as a spatial dimension for history of the objects. The proposed techniques can make conventional object-relational databases to support spatiotemporal databases system by the implementation and inheritance of abstract data types. We define and implement spatial and temporal classes as superclass. And, spatiotemporal classes inherits and extends the classes. The proposed extensions make it easy that conventional database systems not only are transformed into the spatiotemporal database systems, but also do not need to be changed to support spatiotemporal applications.

• Journal of KIISE:Databases
• /
• v.28 no.4
• /
• pp.529-544
• /
• 2001

Prefetching is an effective method to minimize the number of roundtrips between the client and the server in database management systems. In this paper we propose new notions of the type-level access pattern and the type-level access locality and developed an efficient prefetchin policy based on the notions. The type-level access patterns is a sequence of attributes that are referenced in accessing the objects: the type-level access locality a phenomenon that regular and repetitive type-level access patterns exist. Existing prefetching methods are based on object-level or page-level access patterns, which consist of object0ids of page-ids of the objects accessed. However, the drawback of these methods is that they work only when exactly the same objects or pages are accessed repeatedly. In contrast, even though the same objects are not accessed repeatedly, our technique effectively prefetches objects if the same attributes are referenced repeatedly, i,e of there is type-level access locality. Many navigational applications in Object-Relational Database Management System(ORDBMs) have type-level access locality. Therefore our technique can be employed in ORDBMs to effectively reduce the number of roundtrips thereby significantly enhancing the performance. We have conducted extensive experiments in a prototype ORDBMS to show the effectiveness of our algorithm. Experimental results using the 007 benchmark and a real GIS application show that our technique provides orders of magnitude improvements in the roundtrips and several factors of improvements in overall performance over on-demand fetching and context-based prefetching, which a state-of the art prefetching method. These results indicate that our approach significantly and is a practical method that can be implemented in commercial ORDMSs.

• Journal of the Korean Society for information Management
• /
• v.21 no.2
• /
• pp.189-210
• /
• 2004

The purpose of this study is to evaluate the performance of XML retrieval based on ORDBMSs(Object-Relational Database Management Systems) approach. This paper describes indexing and retrieval methods for XML documents and the methodologies of experiments at INEX(Initiative for the Evaluation of XML retrieval). Like any other traditional information retrieval experiment, the test collection was consists of documents, topics/queries, task, relevance assessments and evaluation. EXIMA$^{TM}$ Supply, a kind of native XML DB based on ORDBMS technologies, is used for this experiment. Although this approach has many benefits, for example, no delay in storing and searching XML documents. but it showed relatively disappointed retrieval performance at INEX 2002. This result may caused since the given topics had to be decomposed and modified to be processed by the XPath processor, and during this modification the original meaning of topics can be changed inevitably and some important information nay pass over.r.

• Journal of Internet Computing and Services
• /
• v.3 no.1
• /
• pp.29-40
• /
• 2002

The information exchange on the using of XML such as B2B electronic is common. So the efficient method to store XML message in database is needed. Because the ORDBMS is extended to ORDBMS for supporting multimedia application such as Oracle8i, 9i, Informix and SQL2000 server, SQL2, the standard RDB is extended to SQL3 for ORDB, And the XML application based on java such as J2EE is extended. Therefor it is necessary for the efficient connection methods based on JDBC between XML application and database system. In this paper, the methodology a transformation XML DTD to SQL3 schema is proposed. For the transformation, first the methods of transformation XML DTD to object model in UML class diagram are proposed. And then the methods of mapping transferred object models to SQL3 schema are proposed. This approach for transform::1lion XML. DTD to SQL3 schema such as Oracle8i, 9i, Informix and SQL2000 server based on java is proposed in this paper, can be used in database design to build XML applications based on ORDB.

• Journal of KIISE:Databases
• /
• v.31 no.4
• /
• pp.432-443
• /
• 2004

As the XML data has been widely used in the Internet, it is necessary to store and retrieve the XML data by using DBMSs. However, relational DBMSs suffer from the model difference between graph structure of the XML data and table forms in relational databases. We propose an ORDBMS-based DTD-dependent XML data management system Xing. Xing stores XML data in a DTD-dependent form in an object database. Since the object database schema has a graph structure and supports multi-valued attributes, mapping from an XML data model and queries into an object data model and OQLs is a simple problem. For rapid storing of large quantities of the XML data, we use SAX parser with customized Xing-tree which requires a small memory space compared with the DOM-tree. Xing also returns the query result in an XML document form. We have implemented the Xing system on top of UniSQL object-relational DBMS for the validity checking and performance comparison. For XML genome data from GenBank, and experimental evaluation shows that Xing can provide significant performance improvement (maximum 10 times) compared with the relational approach.

• IE interfaces
• /
• v.10 no.2
• /
• pp.79-90
• /
• 1997

Documents in a traditional PDM(Product Data Management) system have been managed in a form of scanned document files or electronic documents developed by specific tools. Though each tool manages documents with its own systematical methods, it has drawbacks in data search, data integration and interchange, etc. For this reason, in this research we propose an efficient document management system for PDM by using the SGML(Standard Generalized Markup Language), one of CALS and ISO standards for document interchanges. Among documents to be managed in PDM, the engineering change notification (ECN) is taken into account. The DTD (Document Type Definition) has been constucted based on the logical analysis of the documents format, In addition, based on the DTD, DB classes have been designed by object-oriented paradigms and a prototype for document input/output and search has been developed using UniSQL ORDBMS (Object-Relational DBMS) and PowerBuilder under the client/server environment.