I have created an extension and created zip file of extension so that I can install it through Magento Connect. When I uninstall my custom extension using Magento Connect it will only delete my extension files and folders but database tables of my extension are not deleted.
I also want to remove my database table of extension. I want all process to be done automatically not by using phpmyadmin and do it manually or writing any upgrade script because What I want when my extension is being used by user so they will not face any issue.
Sadly, there is no rollback or uninstall script as you may find those on other framework.
The install and data folders of modules are only meant to bump version up but there is no way provided by the framework to bump it down or in your case remove it totally.
来源：https://stackoverflow.com/questions/34657791/uninstall-magento-custom-extension-with-its-database