Overview - ISO/IEC 9075-14:2023 (SQL/XML)
ISO/IEC 9075-14:2023, Part 14 of the SQL standard family, defines the XML-related specifications for SQL (SQL/XML). It standardizes how XML data is represented, manipulated, validated, serialized, parsed and mapped to/from SQL constructs. The standard provides formal syntax and semantic rules for XML value expressions, XML-specific SQL functions and predicates, schema mapping, and integration points for embedded and dynamic SQL, client interfaces, and diagnostics.
Key technical topics and requirements
The standard’s table of contents shows the major technical areas it covers - key topics include:
- XML data types and value semantics
- Definitions and behavior of SQL XML types, comparisons, assignment and operations on XML values.
- XML-specific expressions and functions
- XML construction and manipulation constructs such as XMLQUERY, XMLPARSE, XMLVALIDATE, XMLelement, XMLforest, XMLtext and XMLconcatenation.
- Mappings between SQL and XML
- Comprehensive mapping rules: SQL identifiers ↔ XML names, SQL datatypes ↔ XML schema datatypes, table/schema/catalog to XML elements/documents, and value conversions.
- XQuery integration and contexts
- Rules for creating XQuery expression contexts, handling XQuery document nodes, and mapping XQuery atomic values to SQL.
- Serialization, parsing and validation
- Serialization of XML values, parsing strings as XML, constructing copies, and validating XML against registered XML schemas.
- SQL syntax extensions and session options
- New lexical elements, scalar expressions, predicates (XMLCONTENT, XMLEXISTS, XMLDOCUMENT, XMLVALID), XML-returning clauses and XML options for SQL sessions.
- Schema definition, manipulation and information schema
- DDL elements for columns, views, routines and user-defined types plus Information Schema and Definition Schema views/tables for XML metadata.
- Interfaces and runtime
- Rules for embedded SQL, dynamic SQL, call-level interfaces (CLI), SQL-invoked routines, diagnostics and privileges related to XML handling.
Practical applications and who uses it
ISO/IEC 9075-14:2023 is essential for:
- DBMS vendors implementing standardized XML storage, query and mapping behavior to ensure portability.
- Application developers building XML-enabled applications that use SQL for data access, transformation or exchange.
- Data architects / integrators designing relational-to-XML mappings for APIs, web services, data interchange, and document-centric storage.
- Tooling and middleware providers that serialize/parse/validate XML within SQL contexts (ETL, reporting, XML publishing).
- Standards bodies and auditors checking conformance and interoperability of SQL/XML implementations.
Related standards
- ISO/IEC 9075 (the broader SQL standard series) - Part 14 extends SQL with XML-specific rules.
- XML-related W3C specs commonly used alongside this standard: XML Schema (XSD) and XQuery (for expression semantics).
For implementation details, syntax and normative rules consult the full ISO/IEC 9075-14:2023 publication.
Open preview (PDF)Information technology — Database languages SQL — Part 14: XML-Related Specifications (SQL/XML)
