• 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 KIPS Transactions:PartD
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• v.11D no.2
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• pp.305-316
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• 2004

XML is becoming the de facto standard for data exchange over the Internet as a semistructured data which properties are irregular and incomplete. Therefore, to handle these data efficiently. what we use storage devices and storage techniques are Primary factors. In this paper, we developed storage techniques, which take the virtues of an object-relational database and support various query types needed for XML query languages without regard to the DTD. The techniques are capable with connecting naturally with conventional data and reducing overheads caused by the characteristics of an XML data model.

• The KIPS Transactions:PartD
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• v.11D no.7 s.96
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• pp.1349-1356
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• 2004

The interest of version management is increasing in electronic commerce requiring data mining and documents processing system related to digital governmentapplications. In this paper, we define a change set that is to manage historicalinformation and to maintain XML documents during a long period of time and propose several storage policies of XML documents using a change set. A change set includes a change oper-ation set and temporal dimensions and a change operation set is composed with schema change operations and data change operations. We pro-pose three storage policies using a change set. Three storage policies are (1) storing all the change sets, (2) storing the change sets and the versions periodically. (3) storing the aggregation of change sets and the versions at a point of proper time. Also, we compare the performance between the existing storage policy and the proposed storage policies. Though the performance evaluation, we show that the method to store the aggregation of change sets and the versions at a point of proper time outperforms others.

• Journal of Korea Multimedia Society
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• v.7 no.1
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• pp.1-11
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• 2004

In this paper. we propose a storage system for XML documents using relational databases. Additional processing is required to store XML documents in the relational databases due to the discrepancy between XML structures and relational schema. This study aims to store XML documents with DTD in the relational databases. We propose the association inlining that exploits shred inlining and hybrid inlining and avoids relation fragments and excessive joins. Experiments show some improvements in the performance with the proposed method. The information of the storage structures is extracted from the simplified DTD. Existing map classes are extended in order to map various structures of XML to relational schema. Map classes are defined for various structures such as elements with multiple values, elements with multiple super elements, and elements with recursive structures through analyzing XML documents. Map files that are XML structures and used in generating SQL statements are created by using the extracted information of storage structures and map classes.

• Journal of KIISE:Databases
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• v.34 no.2
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• pp.153-165
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• 2007

XML is widely used in various applications as the standard for representing and exchanging data on the Web. XML Schema is the standard schema for XML and an XML document generated based on the XML Schema is called 'Valid XML document'. The XML Schema validity should be guaranteed after the XML document is updated. In this paper, we design an efficient method that verifies XML Schema validity before update, and so eliminates unnecessary validations. Also, we propose validation algorithms for each update. In addition, we propose the mapping between XML data and XML Schema and a storage method for XML Schema in order to efficiently extract the schema information for the validation. Finally, we compare the performance of the validation according to the storage methods.

• Journal of KIISE:Databases
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• v.33 no.3
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• pp.342-352
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• 2006

Current studies on storing XML data are focused on either mapping XML data to existing RDBMS efficiently or developing a native XML storage. Some native XML storages store each XML node with parsed object form. Clustering, the physical arrangement of each object, can be an important factor to increase the performance with this storing method. In this paper, we propose re-clustering techniques that can store an XML document efficiently. Proposed clustering technique uses path similarities among data nodes, which can reduce page I/Os when returning query results. And proposed technique can process a path query only using small number of clusters as possible instead of using all clusters. This enables efficient processing of path query because we can reduce search space by skipping unnecessary data. Finally, we apply existing clustering techniques to store XML data and compare the performance with proposed technique. Our results show that the performance of XML storage can be improved by using a proper clustering technique.

• 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.

• The KIPS Transactions:PartD
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• v.14D no.6
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• pp.623-632
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• 2007

GML is a markup language presented as exchange standard for geographic information by the OGC(Open GIS Consortium). In spatial network databases, researches for supporting GML(Geographic Markup Language) can be divided into the parsing, the storing and the retrieval of GML documents. Among them, the study on the storage of GML documents is essential for their efficient retrieval. However there is little research on the storing of GML documents whereas there have been a lot of researches on the storing of n documents. Because the storage schema designed for XML documents are not appropriate for geographic information, we, in this paper, propose three storage schema for efficiently storing GML documents including geographic information in order to solve the problem that the XML storage schema store duplicate data and need to search many tables for obtaining elements. In addition, we design and implement a low-level storage manager which can store GML documents using the proposed GML storage schema.

• Journal of the Korea Computer Industry Society
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• v.5 no.1
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• pp.87-100
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• 2004

XML has recently considered as a new standard for data presentation and exchange on the web, many researches are on going to develop applications and index mechanism to store and retrieve XML documents efficiently. In this paper, design a Main-Memory based XML storage system for efficient management of XML document. And propose structured retrieval of XML document tree which reduce the traverse of XML document tree using element type information included user queries. Proposed indexing mechanism has flexibilities for dynamic data update. Finally, for query processing of XML document include Link information, design a index structure of table type link information on observing XLink standards.

• 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.