Fix a bug where DB() tried to set the MySQL-specific 'sql_mode' on all drivers

Supersedes PR #2756
diff --git a/user_guide_src/source/changelog.rst b/user_guide_src/source/changelog.rst
index 93e75c2..b7fa9bb 100644
--- a/user_guide_src/source/changelog.rst
+++ b/user_guide_src/source/changelog.rst
@@ -628,6 +628,7 @@
 -  Fixed a bug (#2691) - nested transactions could end in a deadlock when an error is encountered with *db_debug* set to TRUE.
 -  Fixed a bug (#2515) - ``_exception_handler()`` used to send the 200 "OK" HTTP status code and didn't stop script exection even on fatal errors.
 -  Fixed a bug - Redis :doc:`Caching <libraries/caching>` driver didn't handle connection failures properly.
+-  Fixed a bug (#2756) - :doc:`Database Class <database/index>` executed the MySQL-specific `SET SESSION sql_mode` query for all drivers when the 'stricton' option is set.
 
 Version 2.1.4
 =============