In general, the design of XML schemas involves translating conceptual schemas into XML schemas which aim to be: (i) normalized schemas, and (ii) connected structures in order to achieve good performance on queries. However, these requirements address a trade-off because highly connected XML structures allow data redundancy, and normalized schemas generate disconnected XML structures. This paper describes a workload-based approach which balances this trade-off on translating conceptual schemas into XML structures. An experimental study on an XML database shows that our XML schemas provide high query performance on the relevant elements for the workload and, at the same time, low cost of data redundancy on elements that are not relevant for update operations.

XML has been explored by both research and industry communities. More than 5500 papers were published on different aspects of XML. With so many publications, it is hard for someone to decide where to start. Hence, this paper presents some of the research topics on XML, namely: XML on relational databases, query processing, views, data matching, and schema evolution. It then summarizes some (some!) of the most relevant or traditional papers on those subjects.

Visual data management employed in EDA Frameworks helps in many design tasks, offering various facilities, specially related to the formulation of queries. In the STAR framework, a visual inteiface is the primary user inteiface to the system, allowing access to different managers and offering facilities for browsing and querying design objects. A graphical browser is available, allowing the navigation through design objects stored in the database, such that object properties can be shown and related objects can be investigated, departing from a selected one. Graphical queries can be formulated in an interactive way. Complex queries can be formulated via a textual SQL-like query language, extended with facilities for version manipulation and navigation in the inheritance hierarchy defined by the STAR data model.