如何用我的修改来更新我的symfony模块?

I have a very big problem with symfony module generation as i always make modification in my database (add tables , add columns, changes names, changes columns data-type .....) and i want a good way to build the symfony module without any effect on the modules that i didn't change it and without drop the data in the database... on brief i need to update my symfony module with my changes ONLY.I have a very big problem with symfony module g