Magento: Upgrading mysql setup of a module

MyModule. Its version is 0.1.0. Now, you want to do some database changes for the module. You have the mysql setup file (mysql install file) mysql4-install-0.1.0.php inMyModule/sql/mymodule_setup folder of your module.
You don’t need to make direct changes to database. You can upgrade your module to make your necessary database changes. To do so,
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1) You need to create a new mysql upgrade file inside MyModule/sql/mymodule_setupfolder.

Let us suppose that you are going to change the version of your module from 0.1.0 to 0.1.1.

The mysql upgrade file name should be mysql4-upgrade-0.1.0-0.1.1.php

The upgrade format is like mysql4-upgrade-CURRENT_VERSION-UPGRADED_VERSION.php

2) Write necessary sql statements in the newly added mysql upgrade file.

3) You have to change the version in MyModule/etc/config.xml as well.

Change the version like 0.1.1. 0.1.1 is the new version for our module.

4) Reload your site. And you are done!