diff --git a/borg2-backup.sh b/borg2-backup.sh
index 99750b2..19357c0 100755
--- a/borg2-backup.sh
+++ b/borg2-backup.sh
@@ -311,11 +311,14 @@ BORG_LOG_FILE="${BORG_LOG_DIR}/borg-backup.log"
 [[ -z "${KEEP_YEARLY}" ]] && KEEP_YEARLY=${DEFAULT_KEEP_YEARLY}
 
 
-[[ -z "${DB_TYPE}" ]] && DB_TYPE="${DEFAULT_DB_TYPE}"
-if [[ "${DB_TYPE,,}" = "mysql" ]] ; then
+if [[ -z "${DB_TYPE}" ]] ; then
+   DB_TYPE="${DEFAULT_DB_TYPE}"
+elif [[ "${DB_TYPE,,}" = "mysql" ]] ; then
    [[ -z "${MYSQL_CREDENTIALS}" ]] && MYSQL_CREDENTIALS="${DEFAULT_MYSQL_CREDENTIALS}"
 elif [[ "${DB_TYPE,,}" = "psql" ]] || [[ "${DB_TYPE,,}" = "postgresql" ]] || [[ "${DB_TYPE,,}" = "postgres" ]] ; then
    [[ -z "${PSQL_SYSTEM_USER}" ]] && PSQL_SYSTEM_USER="${DEFAULT_PSQL_SYSTEM_USER}"
+else 
+   fatal "Unknown DB_TYPE '${DB_TYPE}'."
 fi