ISO/IEC 9075 defines the SQL language. The scope of the SQL language is the definition of data structure and the operations on data stored in that structure. ISO/IEC 9075-1:2008, ISO/IEC 9075-2:2008 and ISO/IEC 9075-11:2008 encompass the minimum requirements of the language. Other parts define extensions.
ISO/IEC 9075-9:2008 defines extensions to SQL to support management of external data through the use of foreign-data wrappers and datalink types.