VODataService: a VOResource Schema Extension for Describing Collections and Services
Date:
21 Oct 2016 08:20:00
Publisher:
IVOA
Description:
VODataService refers to an XML encoding standard for a specialized extension of
the IVOA Resource Metadata that is useful for describing data collections and
the services that access them. It is defined as an extension of the core
resource metadata encoding standard known as VOResource [Plante et al. 2008]
using XML Schema. The specialized resource types defined by the VODataService
schema allow one to describe how the data underlying the resource cover the sky
as well as cover frequency and time. This coverage description leverages
heavily the Space-Time Coordinates (STC) standard schema [Rots 2007].
VODataService also enables detailed descriptions of tables that includes
information useful to the discovery of tabular data. It is intended that the
VODataService data types will be particularly useful in describing services
that support standard IVOA service protocols.
VO-DML: a consistent modeling language for IVOA data models
Date:
31 May 2018 09:00:00
Publisher:
IVOA
Description:
This document defines a standard modelling language, or meta-model, for
expressing data models in the IVOA. Adopting such a uniform language for all
models allows these to be used in a homogeneous manner and allows a
consistent definition of reuse of one model by another. The particular language
defined here includes a consistent identification mechanism for model which
allows these to be referenced in an explicit and uniform manner also from other
contexts, in particular from othe IVOA standard formats such as VOTable.
The language defined in this specification is named VO-DML (VO Data Modeling
Language). VO-DML is a conceptual modeling language that is agnostic of
serializations, or physical representations. This allows it to be designed to
fit as many purposes as possible. VO-DML is directly based on UML, and can be
seen as a particular representation of a UML2 Profile. VO-DML is restricted to
describing static data structures and from UML it only uses a subset of the
elements defined in its language for describing "Class Diagrams". Its concepts
can be easily mapped to equivalent data modelling concepts in other
representations such as relational databases, XML schemas and object-oriented
computer languages.
VO-DML has a representation as a simple XML dialect named VO-DML/XML
that must be used to provide the formal representation of a VO-MDL data model.
VO-DML/XML aims to be concise, explicit and easy to parse and use in code that
needs to interpret annotated data sets.
VO-DML as described in this document is an example of a domain specific
modeling language, where the domain here is defined as the set of data and
meta-data structures handled in the IVOA and Astronomy at large. VO-DML
provides a custom representation of such a language and as a side effect allows
the creation and use of standards compliant data models outside of the IVOA
standards context.
