Your ROOT_URL in app.ini is http://192.168.1.7:3000/ but you are visiting http://shqkxh.org:3000/guofu/dolphin-dev/commits/tag/1.0.0/dolphindb/project/scripts
You should set ROOT_URL correctly, otherwise the web may not work correctly.
2. Add `DDBBase` class to decrease repeated class-level constant definitino.
3. Add `DDBExpression` class for single quarter calculation and yoy claculation.
