I'm using Joomla & I go into phpMyAdmin, Straight to the modules table.
For a lot of the tables in the database, I can change the 'id' field of numerous tables, (menu, content) ect .. & then just relink the articles, rebuild the menu from Joomlas backend & all will be fine.
If I change the id value in modules I do not know how to 'rebuild' or relink it, if I change the value it just doesn't show on the website until I revert the value.
It is pretty advanced what you are doing. Thus, you have to deeply know how all tables are linked. Otherwise, you are at risk of generating inconsistencies.
I would not dare to change values at tables directly on a daily basis. I have created batch scripts for migration (after careful testing).
For examples, module instances are also linked to menu items. Then, if you change a module Id, you have to propagate the change to menu associated tables.
