Md. Sumon Shahriar

On Defining Functional Dependency for XML

Functional dependency (FD) is one of the integrity constraints for any data model. In relational data model, FDs are well studied and are widely used in normalization theory and in key algorithm. In recent years, XML has emerged as an widely used data representation and storage format over the world wide web. The growing use of XML has necessitated the XML document semantically stronger. XML functional dependency can be one of the ways to make the XML data semantically richer. In this paper, we propose XML functional dependency (XFD), specially for the purpose of XML data transformation for semantic integration of schemas with integrity constraints. While proposing, we show how XFD is defined on the XML Document Type Definition (DTD) and is satisfied by the XML documents. We introduce the novel concept tuple that produces the semantically correct tuples in the XML document during XFD satisfaction. We show that XML key is a special case of XFD. We also discuss the advantages of our proposal over other previous XFD definitions.

Preserving Functional Dependency in XML Data Transformation

With the advent of XML as a data representation and exchange format over the web, a massive amount of data is being stored in XML. The task of data transformation for integration purposes in XML is getting much importance to the research community. In XML data transformation, a source schema and its conforming data are transformed to a target schema. The source schema often has integrity constraints to enforce semantics. One type of constraints is XML functional dependency (XFD). When a source schema is transformed to a target schema, XFDs can also be transformed. Thus, the problems how schema and data transformation should cause XFD transformation becomes important. We study the effects of transformation on XFDs in this research. Towards this problem, we first define the XFDs over the XML Document Type Definition(DTD) and the satisfactions of XFDs. We then show how XFDs are transformed and valid when the DTDs are transformed. We further investigate whether the transformed XFDs are preserved by the transformed data.

Quality Data for Data Mining and Data Mining for Quality Data: A Constraint Based Approach in XML

As quality data is important for data mining, reversely data mining is necessary to measure the quality of data. Specifically, in XML, the issue of quality data for mining purposes and also using data mining techniques for quality measures is becoming more necessary as a massive amount of data is being stored and represented over the Web. We propose two important interrelated issues: how quality XML data is useful for data mining in XML and how data mining in XML is used to measure the quality data for XML. When we address both issues, we consider XML constraints because constraints in XML can be used for quality measurement in XML data and also for finding some important patterns and association rules in XML data mining. We note that XML constraints can play an important role for data quality and data mining in XML. We address the theoretical framework rather than solutions. Our research framework is towards the broader task of data mining and data quality for XML data integrations.

On Defining Referential Integrity for XML

Referential integrity is one of the integrity constraints for any data model. In relational data model, inclusion dependency (ID) and foreign key (FK) are well studied and are widely used. In last decade, with the growing use of XML as data representation and exchange format over the web, the issue of integrity constraints in XML has received great importance to the database community. In this paper, we propose XML inclusion dependency (XID) and XML foreign key(XFK). When proposing, we show how both XID and XFK can be defined over the Document Type Definition (DTD) and are satisfied by the XML documents. We introduce a novel concept tuple that produces semantically correct values in the XML documents when satisfactions are checked. We also show that XFK is defined with the combination of XID and XML key.

On the Performances of Checking XML Key and Functional Dependency Satisfactions

We propose an implementation and analyze the performances of checking XML key and functional dependency (XFD) satisfaction. The work is based on the definitions of XML key and XFD we proposed for the ordered XML model. It investigates how the number of occurrences of elements in the document and the number of paths in the constraints affect the behavior of XML key and XFD satisfaction checking. The results of the study show that both XML key and XFD can be checked in linear time with the number of tuples and with the number of paths involved in key and XFD. Also, XFD can be checked linearly with the number of XFDs.

Towards the preservation of functional dependency in XML data transformation

With the advent of XML as a data representation and exchange format over the web, a massive amount of data is being stored in XML. As the use of XML grows rapidly, the task of data transformation for integration purposes in XML is getting much importance to the research community. In XML data transformation, a source schema and its conforming data are transformed to a target schema and its conforming data respectively. The source schema often has integrity constraints to enforce semantics. One type of constraints is XML functional dependency (XFD). When a source schema is transformed to a target schema, XFDs can also be transformed. Thus, the problem how schema and data transformation should cause XFD transformation becomes important. In this paper, we study the transformation of XFDs. Towards this problem, we first define the XFDs over the XML document type definition (DTD) and the satisfactions of XFDs. We then show how XFDs are transformed and whether XFDs are valid when the DTDs are transformed. We further investigate whether the transformed XFDs are preserved by the transformed data.

Checking Satisfactions of XML Referential Integrity Constraints

Recently we proposed referential integrity constraints for XML. In defining two important referential constraints namely XML inclusion dependency and XML foreign key, we considered ordered XML data model to capture the correct semantics of data when tuples are to be produced. In this paper, we report on the performances of checking both XML inclusion dependency and XML foreign key. We show that both these constraints can be checked in linear time in the context of number of tuples and the number of paths.

Transition of Keys in XML Data Transformation

Transformation of a source schema to a target schema is an important activity in data integration. In XML data transformation for data integration purposes, when an XML source schema with its conforming data is transformed to the target XML schema, one of the important XML constraints, XML keys that are defined on the source schema for expressive semantics can also be transformed. Thus, whether keys should be transformed and preserved, and if not preserved, whether keys can be captured in another form of XML constraints are important questions. To answer these questions, first, we define XML keys and XML functional dependencies(XFD) on document type definition (DTD). Second, we show key preservation in transformation. If keys are not preserved, we then show how to capture them as XFDs. We term this as key transition. Our research about the XML key preservation and transition is towards handling the issues of integrity constraints in XML data integration.

Preserving key in XML data transformation

Transformation of XML data is an important task in data exchange, data publishing and data integration. Specifically in data integration, data in XML sources is transformed to match the target schema. Some of these sources have XML keys defined. When the data is transformed, the keys also need to be transformed for constraint comparisons, consistency checking and unification in the target schema. Thus, how the keys are transformed, and whether the transformed keys are valid and preserved to the target schema are important problems in XML data transformation and integration. Towards this problem, we firstly define XML keys and their satisfactions. We then study how keys are transformed and whether transformed keys are valid when a source schema is transformed to a target schema. Finally we show whether the transformed keys are satisfied by the transformed document.

Preserving Referential Integrity Constraints in XML Data Transformation

We study the transformation and preservation of XML referential integrity constraints in XML data transformation for integration purposes in this paper. In transformation and preservation, we consider XML inclusion dependency and XML foreign key. We show how XML referential constraints should be transformed and preserved using important transformation operations with sufficient conditions.