How does Virtuoso generate XML from relational data?
Virtuoso has several mechanisms for transforming SQL data into XML. One option is the “FOR XML” clause, which is a SQL option that can convert the output of a SELECT statement into a tree. • SQLX is the standard SQL way of creating XML content from relational data. Special aggregates and functions allow composing trees in queries • Mapping Schemas – A mapping schema is an XML schema, which defines how the data is to be extracted from, joins of relational tables. When an XPATH query is evaluated against a mapping schema, Virtuoso generates an SQL query, which will retrieve only the required rows and then generate the XML tree.
