Several major database systems provide extensions to support the management and analysis of spatial data in a relational database system (IBM02, Ora01 and IBM01). The functionality is also standardized in ISO/IEC 13249 SQL/MM. This paper presents part 3 of the standard and discusses it critically. The spatial data types and methods on these types are explained. The information schema, showing spatial columns and spatial reference systems, is an important part for the handling of spatial data. It is described in the paper as well.