You will find an explanation of the term in User Manual: SAP DB ® Definition of Terms ®
This document describes the functionality of the database system provided by the INTERNAL SQL mode.
Only those SQL statements are described for which the same SQL mode is used to generate the object and execute the statement for the object. If database objects are created in one SQL mode and addressed in another, the object may have properties that are not known in the current SQL mode and, therefore, cannot be described.
SQL statement for specifying the SQL mode
CONNECT statement