Part 2 of the standard, ISO 19125-2 (SFA-SQL), defines a "SQL/MM" language binding API for SQL under the prefix "ST_".
The ISO/IEC 13249-3 SQL/MM Spatial extends the Simple Features data model, originally based on straight-line segments, adding circular interpolations (e.g. circular arcs) and other features like coordinate transformations and methods for validating geometries, as well as Geography Markup Language support.
The spatial extension adds the datatypes "Circularstring", "CompoundCurve", "CurvePolygon", "PolyhedralSurface", the last of which is also included into the OGC standard.
Direct implementations of Part 2 (SQL/MM) include: Adaptations include: GeoSPARQL is an OGC standard that is intended to allow geospatially-linked data representation and querying based on RDF and SPARQL by defining an ontology for geospatial reasoning supporting a small Simple Features (as well as DE-9IM and RCC8) RDFS/OWL vocabulary for GML and WKT literals.
[16] As of 2012, various NoSQL databases had very limited support for "anything more complex than a bounding box or proximity search".