How to update plugins with database updates if I use svn

This will not be a problem.

WordPress doesn’t provide plugins with an explicit update hook for this reason:

If a plugin is manually updated then this upgrade hook won’t fire. The
best way to manage database upgrades is to do it the same way as
WordPress does it. Store an option containing your plugin’s database
version and check it on the admin_init hook and run the upgrade
routine when it doesn’t match the version in your plugin. Many popular
plugins use this method. It’s definitely the most fool-proof.

[From ticket #19681]

So, each plugin has to do its own check to see if its database version is up to date. Plugins will generally run this check each time WordPress runs, or each time the admin panel is accessed, and update their database if needed. So if the plugin has database updates, they will probably be applied the first time someone visits the site after you run svn up. (Or, for some plugins, until someone visits the administration screens.)