<xs:group name="access_control"><xs:annotation><xs:documentation xml:lang="en">Access control.this group is used for documentation only, not used in XML file.</xs:documentation></xs:annotation><xs:all><xs:element ref="grant_statement"/><xs:element ref="grant_privilege_statement"/><xs:element ref="privileges"/><xs:element ref="role_definition"/><xs:element ref="grant_role_statement"/><xs:element ref="drop_role_statement"/><xs:element ref="revoke_statement"/></xs:all></xs:group>