Variadic genericity through linguistic reflection : a performance evaluation

This work is partially supported by the EPSRC through Grant GR/L32699 “Compliant System Architecture” and by ESPRIT through Working Group EP22552 “PASTEL”.The use of variadic genericity within schema definitions increases the variety of databases that may be captured by a single specification. For example, a class of databases of engineering part objects, in which each database instance varies in the types of the parts and the number of part types, should lend itself to a single definition. However, precise specification of such a schema is beyond the capability of polymorphic type systems and schema definition languages. It is possible to capture such generality by introducing a level of interpretation, in which the variation in types and in the number of fields is encoded in a general data structure. Queries that interpret the encoded information can be written against this general data structure. An alternative approach to supporting such variadic genericity is to generate a precise database containing tailored data structures and queries for each different instance of the virtual schema.1 This involves source code generation and dynamic compilation, a process known as linguistic reflection. The motivation is that once generated, the specific queries may execute more efficiently than their generic counter-parts, since the generic code is “compiled away”. This paper compares the two approaches and gives performance measurements for an example using the persistent languages Napier88 and PJama.Postprin

The Concept of Representation Capability of Databases and its Application in IS Development

The representation capability of an information system in general and a database in particular seems an important and yet elusive concept, which is concerned with, in our view, how a database ever becomes capable of representing real-world objects accurately or otherwise. To explore how to approach and then define this concept, we explore what is meant and required by the statement that a database connection (i.e., a connection between database constructs such as entities in an Entity-relationship (ER) diagram and relations in a relational schema that are made available by a database) refers to, represents and accurately represents a real-world relation respectively. This approach is proven to be insightful and effective. We also find a sufficient and necessary condition for a database connection to be able to accurately represent a real-world relation, which is that the information content of the database connection includes the real-world relation. All these make the concept of representation capability of a database approachable and definable. Furthermore, another different and yet related concept, namely the representation capacity of a database, can also be defined based on the representation capability of a database, which is ‘all the real-world relations that can be represented by the constructs that are made possible and available by the database’. Our theoretical work draws on semiotics, the semantic theory of information presented by Dretske and the information channel theory by Barwise and Seligman, and our practical work involves an information system’s development

An Agent-Based Approach For Collaborative Schema Design

Data modeling is a crucial step towards incorporating successful databases in an organization. The design, operational behavior, and use of a database are affected by the meaning of the information it manages. The cognitive capability of the human mind is rather complex; it has the capability to visualize a problem domain in a variety of perspectives. It would be interesting to conceive of an application, by which the best thoughts of human minds can be pooled together to create a conceptual schema design for a database. Thus, the database design would be enhanced if capabilities were provided for collaboration between different designers working on different platforms at different locations and even at different times but working on the same database design. This paper describes an agent- based approach, using an agent-based architecture communicating through the Internet, which promotes the collaborative conceptual schema design. The agent communication was to be developed using KQML (Knowledge Query Manipulation Language) in Java. The prototype of the system developed captures only the static properties of a system. The dynamic aspects of the operations are resolved by considering certain additional aspects that are not exactly database objects, but are associated with a database occurrence which changes as a result of an operation. These are implementation issues that must be taken care by a database designer during the implementation

Relational database of treatment planning system information

The purpose of the present work was to develop a relational database and associated applications to facilitate retrospective review of data present in radiation treatment plans. The data source was a commercial radiation treatment planning system (Pinnacle3, Philips Medical Systems, Milpitas CA), which is specifically characterized by an open data storage format and internal scripting capability. The database is an open-source, relational database (PostgreSQL, PostgreSQL Global Development Group, http://www.postgresql.org). The data is presented through a web interface in addition to being fully query-accessible using standard tools. A database schema was created to organize the large collection of parameters used to generate treatment plans as well as the parameters that characterized these plans. The system was implemented through a combination of the treatment planning systems internal scripting language and externally executed code. Data is exported in a way that is transparent to the user, through integration into an existing and routinely-used process. The system has been transparently incorporated into our radiation treatment planning workflow. The website-based database interface has allowed users with minimal training to extract information from the database

IVOA Recommendation: IVOA Support Interfaces

This document describes the minimum interface that a (SOAP- or REST-based) web service requires to participate in the IVOA. Note that this is not required of standard VO services developed prior to this specification, although uptake is strongly encouraged on any subsequent revision. All new standard VO services, however, must feature a VOSI-compliant interface. This document has been produced by the Grid and Web Services Working Group. It has been reviewed by IVOA Members and other interested parties, and has been endorsed by the IVOA Executive Committee as an IVOA Recommendation. It is a stable document and may be used as reference material or cited as a normative reference from another document. IVOA's role in making the Recommendation is to draw attention to the specification and to promote its widespread deployment. This enhances the functionality and interoperability inside the Astronomical Community

Schema architecture and their relationships to transaction processing in distributed database systems

We discuss the different types of schema architectures which could be supported by distributed database systems, making a clear distinction between logical, physical, and federated distribution. We elaborate on the additional mapping information required in architecture based on logical distribution in order to support retrieval as well as update operations. We illustrate the problems in schema integration and data integration in multidatabase systems and discuss their impact on query processing. Finally, we discuss different issues relevant to the cooperation (or noncooperation) of local database systems in a heterogeneous multidatabase system and their relationship to the schema architecture and transaction processing