Which of the following is not true about XML Columns ?
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Data can be retrieved by SQL
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Data can be retrieved by XQUERY
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XML Columns must be altered to accommodate additional parent and child relationships
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Access to any portion of an XML document can be direct ,without reading whole document
XML columns in DB2 store XML documents as parsed hierarchical structures. The beauty of XML columns is their flexibility - they can accommodate any XML structure without requiring schema changes when new parent-child relationships are added. This is a key advantage over relational columns which would require ALTER TABLE statements. Options A, B, and D are all true about XML columns: they support both SQL and XQUERY retrieval, and allow direct access to XML document portions without reading the entire document.
XML columns in DB2 don't need to be altered to accommodate new parent-child relationships because XML is inherently schema-flexible — a document can gain new nested elements without any DDL change to the column itself. This flexibility is part of why XML columns are attractive for semi-structured data, in contrast to relational columns which do require ALTER TABLE for structural changes.