Consider the most recent (O)RDBMS products provided by Oracle, IBM, and Microsoft. Discuss and contrast their support in terms of:

• Storing XML documents (document-oriented approach, data-oriented approach, or combined approach);

• Table-based mapping facilities;

• Schema-oblivious mapping facilities;

• Schema-aware mapping facilities;

• SQL/XML;

• Searching facilities for XML data (full-text search, keyword-based
search, XQuery, RDF, and SPARQL);