XML document design via GN-DTD

Designing a well-structured XML document is important for the sake of readability and maintainability. More importantly, this will avoid data redundancies and update anomalies when maintaining a large quantity of XML based documents. In this paper, we propose a method to improve XML structural design by adopting graphical notations for Document Type Definitions (GN-DTD), which is used to describe the structure of an XML document at the schema level. Multiples levels of normal forms for GN-DTD are proposed on the basis of conceptual model approaches and theories of normalization. The normalization rules are applied to transform a poorly designed XML document into a well-designed based on normalized GN-DTD, which is illustrated through examples

Corporate Data Obesity: 50 Percent Redundant

In this essay, we report what we have observed with regard to status quo of corporate information systems in real world from our experiences of twenty years of data management practices. It is considered to be serious in that data are too conveniently and frequently replicated to make information systems improperly behave in terms of their quality standards including response time. Average ratio of data replication in a site is astonishingly judged to be more than 50 percent of a whole corporate database. It is in reality about 65 percent in average to our knowledge. Presenting this paper to academia has been motivated by our strong belief and evidence that most of the redundancy can effectively and systemically be removed from the very start of information system development. We also noted that field workers including database administrators in corporate environment tend to think data part of IS and program part of IS mixed together from the start of IS design and popularity of this tendency eventually caused a lot of entanglement that could hardly be dealt with later by themselves. We therefore present a couple of mandates that must be respected in order not to get involved in such a perplexity

A schema-only approach to validate XML schema mappings

Since the emergence of the Web, the ability to map XML data between different data sources has become crucial. Defining a mapping is however not a fully automatic process. The designer needs to figure out whether the mapping is what was intended. Our approach to this validation consists of defining and checking certain desirable properties of mappings. We translate the XML schemas and the mapping into first-order logic formalism and apply a reasoning mechanism to check the desirable properties automatically, without assuming any particular instantiation of the schemas.Preprin

Validation of schema mappings with nested queries

With the emergence of the Web and the wide use of XML for representing data, the ability to map not only flat relational but also nested data has become crucial. The design of schema mappings is a semi-automatic process. A human designer is needed to guide the process, choose among mapping candidates, and successively refine the mapping. The designer needs a way to figure out whether the mapping is what was intended. Our approach to mapping validation allows the designer to check whether the mapping satisfies certain desirable properties. In this paper, we focus on the validation of mappings between nested relational schemas, in which the mapping assertions are either inclusions or equalities of nested queries. We focus on the nested relational setting since most XML’s Document Type Definitions (DTDs) can be represented in this model. We perform the validation by reasoning on the schemas and mapping definition. We take into account the integrity constraints defined on both the source and target schema.Preprin