Desirable properties for XML update mechanisms

The adoption of XML as the default data interchange format and the standardisation of the XPath and XQuery languages has resulted in significant research in the development and implementation of XML databases capable of processing queries efficiently. The ever-increasing deployment of XML in industry and the real-world requirement to support efficient updates to XML documents has more recently prompted research in dynamic XML labelling schemes. In this paper, we provide an overview of the recent research in dynamic XML labelling schemes. Our motivation is to define a set of properties that represent a more holistic dynamic labelling scheme and present our findings through an evaluation matrix for most of the existing schemes that provide update functionality

FibLSS: A scalable label storage scheme for dynamic XML updates

Dynamic labeling schemes for XML updates have been the focus of significant research activity in recent years. However the label storage schemes underpinning the dynamic labeling schemes have not received as much attention. Label storage schemes specify how labels are physically encoded and stored on disk. The size of the labels and their logical representation directly influence the computational costs of processing the labels and can limit the functionality provided by the dynamic labeling scheme to an XML update service. This has significant practical implications when merging XML repositories such as clinical studies. In this paper, we provide an overview of the existing label storage schemes. We present a novel label storage scheme based on the Fibonacci sequence that can completely avoid relabeling existing nodes under dynamic insertions. Theoretical analysis and experimental results confirm the scalability and performance of the Fibonacci label storage scheme in comparison to existing approaches

Order based labeling scheme for dynamic XML (extensible markup language) query processing

Thesis (Master)--Izmir Institute of Technology, Computer Engineering, Izmir, 2012Includes bibliographical references (leaves: 43-46)Text in English; Abstract: Turkish and Englishix, 55 leavesNeed for robust and high performance XML database systems increased due to growing XML data produced by today’s applications. Like indexes in relational databases, XML labeling is the key to XML querying. Assigning unique labels to nodes of a dynamic XML tree in which the labels encode all structural relationships between the nodes is a challenging problem. Early labeling schemes designed for static XML document generate short labels; however, their performance degrades in update intensive environments due to the need for relabeling. On the other hand, dynamic labeling schemes achieve dynamicity at the cost of large label size or complexity which results in poor query performance. This thesis presents OrderBased labeling scheme which is dynamic, simple and compact yet able to identify structural relationships among nodes. A set of performance tests show promising labeling, querying, update performance and optimum label size

Dynamic Containment Labeling Scheme for XML

提出了适用于XMl文档更新环境下的区间编码方法——dClS(dynAMIC COnTAInMEnT lAbElIng SCHEME).dClS将基于整数的编码泛化到基于向量的编码,扩展了传统静态区间编码方法,有效避免了XMl文档更新时的重新编码.不论文档更新与否,dClS都显示了良好的性能:dClS利用基于整数的静态区间编码方法进行初始编码,在文档不更新的环境下,具有较高的存储效率和查询性能;同时,dClS将整数视为特殊向量,不仅能够支持文档更新,而且更新效率高;特别是倾斜插入时,dClS可以避免编码位长的快速增加.实验结果表明,与已有的动态区间编码方法相比,dClS具有更好的性能.A novel containment scheme called DCLS is proposed to effectively process updates in dynamic XML data.DCLS generalizes the static containment scheme from integer order to vector order and thus completely avoids re-labeling when XML data updating.Moreover,DCLS is compact and efficient regardless of whether the documents are updated or not.On the one hand,DCLS uses integer-based static containment scheme for initial labeling,which yields compact size and excellent query efficiency for static documents.On the other hand,DCLS takes the integer as special vector,which not only deals with the case of document updating,but also achieves high query performance.Most importantly,DCLS can effectively avoid the rapid increase of labeling size for the case of skewed insertions.Experimental results confirm the benefits of this approach compared to previous dynamic containment schemes.国家自然科学基金(50604012);中央高校基本科研业务费专项资金(2011121049

Level based labeling scheme for extensible markup language (XML) data processing

Thesis (Master)--Izmir Institute of Technology, Computer Engineering, Izmir, 2010Includes bibliographical references (leaves: 56-57)Text in English; Abstract: Turkish and Englishx, 70 leavesWith the continuous growth of data in businesses and the increasing demand for reaching that data immediately, raised the need of having real time data warehouses. In order to provide such a system, the ETL mechanism will need to be very efficient on updating data. From the literature surveys, it has been observed that there are many studies performed on efficient update of the relational data, while there is limited amount of study on updating the XML data. With the extensible structure and effective performance on data exchange, the usage of XML data structure is increasing day by day. Like relational databases, real time XML databases also need to be updated continuously. The hierarchic characteristic of XML required the usage of tree representations for indexing the data since they provide necessary means to capture different relationships between the nodes. The principal purpose of this study is to define and compare algorithms which label the XML tree with an effective update mechanism. Proposed labeling algorithms aim to provide a mechanism to query and update the XML data by defining all relations between the nodes. In the experimental evaluation part of this thesis, all algorithms is examined and tested with an existing labeling algorithm

Querying and Updating XML Data based on Node Labeling Schemes

Ph.DDOCTOR OF PHILOSOPH

Pentagonal scheme for dynamic XML prefix labelling

In XML databases, the indexing process is based on a labelling or numbering scheme and generally used to label an XML document to perform an XML query using the path node information. Moreover, a labelling scheme helps to capture the structural relationships during the processing of queries without the need to access the physical document. Two of the main problems for labelling XML schemes are duplicated labels and the cost efficiency of labelling time and size. This research presents a novel dynamic XML labelling scheme, called the Pentagonal labelling scheme, in which data are represented as ordered XML nodes with relationships between them. The update of these nodes from large scale XML documents has been widely investigated and represents a challenging research problem as it means relabelling a whole tree. Our algorithms provide an efficient dynamic XML labelling scheme that supports data updates without duplicating labels or relabelling old nodes. Our work evaluates the labelling process in terms of size and time, and evaluates the labelling scheme’s ability to handle several insertions in XML documents. The findings indicate that the Pentagonal scheme shows a better initial labelling time performance than the compared schemes, particularly when using large XML datasets. Moreover, it efficiently supports random skewed updates, has fast calculations and uncomplicated implementations so efficiently handles updates. Also, it proved its capability in terms of the query performance and in determining the relationships.Libyan governmen

A graphical XML query language based on ORA-SS

Ph.DDOCTOR OF PHILOSOPH

Labelling Dynamic XML Documents: A GroupBased Approach

Documents that comply with the XML standard are characterised by inherent ordering and their modelling usually takes the form of a tree. Nowadays, applications generate massive amounts of XML data, which requires accurate and efficient query-able XML database systems. XML querying depends on XML labelling in much the same way as relational databases rely on indexes. Document order and structural information are encoded by labelling schemes, thus facilitating their use by queries without having to access the original XML document. Dynamic XML data, data which changes, complicates the labelling scheme. As demonstrated by much research efforts, it is difficult to allocate unique labels to nodes in a dynamic XML tree so that all structural relationships between the nodes are encoded by the labels. Static XML documents are generally managed with labelling schemes that use simple labels. By contrast, dynamic labelling schemes have extra labelling costs and lower query performance to allow random updates irrespective of the document update frequency. Given that static and dynamic XML documents are often not clearly distinguished, a labelling scheme whose efficiency does not depend on updating frequency would be useful. The GroupBased labelling scheme proposed in this thesis is compatible with static as well as dynamic XML documents. In particular, this scheme has a high performance in processing dynamic XML data updates. What differentiates it from other dynamic labelling schemes is its uniform behaviour irrespective of whether the document is static or dynamic, ability to determine all structural relationships between nodes, and the improved query performance in both types of document. The advantages of the GroupBased scheme in comparison to earlier schemes are highlighted by the experiment results

Compressing Labels of Dynamic XML Data using Base-9 Scheme and Fibonacci Encoding

The flexibility and self-describing nature of XML has made it the most common mark-up language used for data representation over the Web. XML data is naturally modelled as a tree, where the structural tree information can be encoded into labels via XML labelling scheme in order to permit answers to queries without the need to access original XML files. As the transmission of XML data over the Internet has become vibrant, it has also become necessary to have an XML labelling scheme that supports dynamic XML data. For a large-scale and frequently updated XML document, existing dynamic XML labelling schemes still suffer from high growth rates in terms of their label size, which can result in overflow problems and/or ambiguous data/query retrievals. This thesis considers the compression of XML labels. A novel XML labelling scheme, named “Base-9”, has been developed to generate labels that are as compact as possible and yet provide efficient support for queries to both static and dynamic XML data. A Fibonacci prefix-encoding method has been used for the first time to store Base-9’s XML labels in a compressed format, with the intention of minimising the storage space without degrading XML querying performance. The thesis also investigates the compression of XML labels using various existing prefix-encoding methods. This investigation has resulted in the proposal of a novel prefix-encoding method named “Elias-Fibonacci of order 3”, which has achieved the fastest encoding time of all prefix-encoding methods studied in this thesis, whereas Fibonacci encoding was found to require the minimum storage. Unlike current XML labelling schemes, the new Base-9 labelling scheme ensures the generation of short labels even after large, frequent, skewed insertions. The advantages of such short labels as those generated by the combination of applying the Base-9 scheme and the use of Fibonacci encoding in terms of storing, updating, retrieving and querying XML data are supported by the experimental results reported herein