Mustafa Atay

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Storing and querying XML documents using a RDBMS is a challenging problem since one needs to resolve the conflict between the hierarchical, ordered nature of the XML data model and the flat, unordered nature of the relational data model. This conflict can be resolved by the following XML-to-Relational mappings: schema mapping, data mapping and query(More)
Very few research works have been done on XML access control over relational databases despite the fact that there is an undeniable amount of XML data stored in RDBMS. Moreover, the proposed algorithms in the literature have performance drawbacks. In this paper, we propose an efficient and well-defined XML access control model for schema-based relational(More)
XML is rapidly emerging on the World Wide Web as a standard for representing and exchanging data. It is critical to have efficient mechanisms to store and query XML documents to exploit the full power of this new technology. While one approach is to develop native XML repositories that support XML data models and query languages directly, the other approach(More)
XML has emerged as the standard for representing and exchanging data on the World Wide Web. It is critical to have efficient mechanisms to store and query XML data to exploit the full power of this new technology. Several researchers have proposed to use relational databases to store and query XML data. While several algorithms of schema mapping and query(More)
Numerous researchers have proposed to use relational databases to store and query XML documents. In these systems, the elements selected by an XML query are returned to an application either by select mode or by reconstruct mode. For the reconstruct mode, the XML subtrees that are rooted at the selected elements need to be extracted and reconstructed from(More)
Increasing amount of RDF data on the Web drives the need for its efficient and effective management. In this light, numerous researchers have proposed to use RDBMSs to store and query RDF annotations using the SQL and SPARQL query languages. The first few attempts at SPARQL-to-SQL translation revealed non-trivial challenges related to correctness and(More)
Several query mapping algorithms have been proposed to translate XML queries into SQL queries for a schema-based relational XML storage. However, existing query mapping algorithms only support single-valued mapping schemes, in which each XML element type is mapped to exactly one relation, and do not support multi-valued mapping schemes, in which each XML(More)
DTD has been widely used as the schema language for XML documents. A DTD describes the structure of a collection of similar XML documents. The consistency problem of XML DTDs concerns the question that given a DTD D, if there exists any finite XML document that conforms to D. This issue is important because one wants to know whether a DTD specification is(More)
Numerous researchers have proposed to use relational databases to store and query XML documents. One important component of such systems is the XML subtree reconstruction, which reconstructs the subtrees rooted at the matching nodes of an XML query and returns them to the user as the query result. Existing reconstruction algorithms either do not support(More)
With XML becoming a standard for semi-structured documents on the web and a standard for data exchange between different systems in e-commerce and e-business, some database companies are adding XML support to their existing database systems, while on the other hand some other companies coming out with pure or native database systems for XML. In this paper,(More)