• Journal of KIISE:Computing Practices and Letters
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• v.9 no.2
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• pp.109-122
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• 2003

As XML documents become popular in the World Wide Web, a lot of research is being done on XML storage systems that store and manage XML documents using existing DBMSS. However, most of them have been done in the context of relational DBMSS rather than object-relational DBMSS, which have more powerful modeling capability than relational ones. In this paper, we design and implement an XML storage system, ODYSSEUS/XMLStore, for the ODYSSEUS object-relational DBMS that has been under development at KAIST. First, we analyze the mapping from the structure of XML documents to the relational or object-relational database schema. Second, we propose a method for describing the mapping analyzed using a standard language, XML Schema. Third, we propose a storage structure for storing the mapping information specified by the users in the database. Fourth, we propose detailed algorithms for storing XML documents in the relational or object-relational database based on the mapping information provided by the users.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.6A
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• pp.870-884
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• 2000

Among OLAP(On-Line Analytical Processing) approaches, ROLAP(Relational OLAP) based on the star, snowflake schema which offer the multidimensional analytical method has performance problem and MOLAP (Multidimensional OLAP) based on Multidimensional Database System has scalability problem. In this paper, to solve the limitaions of previous approaches, design and implementation of multidimensional data model based on Object-Relation DBMS was proposed. With the extensibility of Object-Relation DBMS, it is possible to advent multidimensional data model which more expressively define multidimensional concept and analysis functions that are optimized for the defined multidimensional data model. In addition, through the hierarchy between data objects supported by Object-Relation DBMS, the aggregated data model which is inherited from the super-table, multidimensional data model, was designed. One these data models and functions are defined, they behave just like a built-in function, w th the full performance characteristics of Object-Relation DBMS engine.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.1C
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• pp.9-17
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• 2005

XML is rapidly spreading as a standard for data representation and exchange, and XML documents are adopted in various applications. According to this trend, researches in database has also focused on efficient storage and retrieval of XML documents. Recently, major (object) relational DBMS vendors support XML functionality, and several native XML DBMSs have been developed in academic or industry side. In addition, various benchmarks have been proposed so as to evaluate these na database performance. In this paper, we evaluate the XBench benchmark using a commercial object-relational DBMS, analyze its performance, and investigate the future improvements of object-relational DBMSs for XML support.

• Journal of the Korea Society of Computer and Information
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• v.8 no.2
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• pp.16-23
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• 2003

In most organizations, the relational DBMS was used for store and manage XML documents due to the pre-established relational DBMS. But, relational DBMS has some problems. They has the possibilities of informational loses in the process of mapping the structure of XML documents to RDB, and they require expensive cost to reflect all XML properties. Thus, this paper was intended to design and implement XML document management system which utilize O2 DBMS-object oriented DBMS in order to overcome the existing problem and reflect all XML Properties. The XML document management system purposed in this thesis has multiple function, such as the library service function for XML documents-check-in/check-out, versioning, user access management-, dynamic indexing and retrieval, and publishing function using style sheet.

• Journal of Korea Multimedia Society
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• v.1 no.2
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• pp.142-153
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• 1998

In this paper, Java Method approach for the integration of Web and Object-Relational DBMS is proposed. For the purpose, we extend to use Java language in programming user-defined function which is one of important characteristic of Object-Relational DBMS with object concept. Therefore we can retrieve not only database objects but also their associated Java methods to run in clients. Finally, to demonstrate the feasibility of the proposed Java Method technique, we designed and implemented this Java method system based on three-tier client/server architecture using JDBC(Java Database Connectivity) and Java RMI(Remote Method Invocation).

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2007.02a
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• pp.163-167
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• 2007

We propose an XML document storage system, called XDMS (XML Document Management System), by using an object-relational DBMS. XDMS generates object database schema from XML Schema and stores the XML documents in an object-relational database. SAX parser is used for understanding the structure of the XML documents, and XDMS transforms the documents into objects in the database. Experiment shows that object-relational databases provide more efficient storage and query model compared with relational databases.

• Journal of KIISE:Computing Practices and Letters
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• v.10 no.1
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• pp.14-24
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• 2004

Views are essential in providing logical data independence for database systems. Object views in object-oriented/object-relational databases have requirements quite different from those of relational databases due to support for object-oriented concepts. Although many commercial object-oriented/object-relational database systems support object views, implementation techniques have not been discussed sufficiently in the literature. In this paper, we devise a technique for implementing views in object-oriented/object-relational databases and apply it to the ODYSSEUS object-relational database system. We first analyze the requirements of object views. Next, to implement object views, we extend the existing query modification algorithm that has been proposed for implementing views in relational databases. Next, we compare the features of the proposed object view with those of object views in commercial object-relational database systems. It is shown that the proposed object view supports all object-oriented concepts such as object identifiers, inheritance, methods, and composite objects, while existing object views support part of them. Last, we propose detailed techniques for implementing the extended query modification algorithm in the ODYSSEUS object-relational database system.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10a
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• pp.45-47
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• 2000

객체관계형 데이터베이스 시스템(objet-relational database management system: ORDBMS)은 멀티미디어 데이터베이스, 지리정보 시스템(geographical information system), CAD/CAM 공학 데이터베이스 등 새로운 응용 분야에 적합한 차세대 데이터베이스 시스템이다. 본 논문에서는 한국과학기술원 첨단정보기술연구센터에서 개발해 오고 있는 오디세우스 객체관계형 멀티미디어 DBMS의 아키텍쳐와 오디세우스의 확장 버전들에 대해서 설명한다. 오디세우스는 다양한 멀티미디어 응용들을 빠르게 지원하기 위해서 엔진 수준에서 필요한 프리미티브를 구현하는 밀결합 아키텍쳐를 채택하고 있다. 현재 밀결합 아키텍쳐로 이미 구현됐거나 개발중인 시스템으로는 텍스트 정보 검색 기능을 밀결합한 정보검색용 DBMS의 오디세우스/IR과 공간 정보 검색 기능을 밀결합한 GIS용 DBMS인 오디세우스/Geo가 있으며, 다양한 멀티미디어 엔진 프리미티브들을 추가적으로 개발중이다. 특히 오디세우스/IR은 성공적으로 실용화되어 현재 여러 사이트에서 사용되고 있으며 이는 오디세우스/IR 아키텍쳐의 우수성을 간접적으로 증명하는 실례들이다. 또한 최근에는 사용자가 쉽게 고성능의 웹 DBMS 응용 프로그램을 작성하도록 도와주는 웹과 DBMS 연동 도구를 개발하였다. 본 논문에서는 이들 시스템에 대한 특징들을 소개하고자 한다.

• Journal of KIISE:Databases
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• v.30 no.2
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• pp.109-124
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• 2003

Although most commercial relational DBMSs Provide a graphical query language for the user friendly interfaces of the databases, few research has been done for graphical query languages in object databases. Expressing complex query conditions in a concise and intuitive way has been an important issue in the design of graphical query languages. Since the object data model and object query languages are more complex than those of the relational ones, the graphical object query language should have a concise and intuitive representation method. We propose a graphical object query language called GOQL (Graphical Object Query Language) for object databases. By employing simple graphical notations, advanced features of the object queries such as path expressions including set attributes, quantifiers, and/or methods can be represented in a simple graphical notation. GOQL has an excellent expressive power compared with previous graphical object query languages. We show that path expressions in XSQL(1,2) can be represented by the simple graphical notations in GOQL. We also propose an algorithm that translates a graphical query in GOQL into the textual object query with the same semantics. We finally describe implementation results of GOQL in the Internet environments.

• Journal of Korea Multimedia Society
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• v.11 no.4
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• pp.415-422
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• 2008

With the increasing use of XML, considerable research is being conducted on the XML document management systems for more efficient storage and searching of XML documents. Depending on the base systems, these researches can be classified into object-oriented DBMS (OODBMS) and relational DBMS (RDBMS). OODBMS-based systems are better suited to reflect the structure of XML-documents than RDBMS based ones. However, using an XML parser to map the contents of documents to relational tables is a better way to construct a stable and effective XML document management system. The proposed X-Binder system uses an RDBMS-based inverted index; this guarantees high searching speed but wastes considerable storage space. To avoid this, the proposed system incorporates a path combining module agent that combines paths with sibling relations, and stores them in a single row. Performance evaluation revealed that the proposed system reduces storage wastage and search time.