Where are sharepoint apps(list,contentypes) stored?

Question

As far as I know in sharepoint 2013 app I can deploy lists, content types, etc. And as far as I know these resources are for that app only. So other apps wont be able to access them.

The question is, where are they stored? Are they stored in content database where the app is installed? is storage isolated for each instance of the app installed?

How can I update an existing content type definition or list definition in an app? in the past I used feature upgrading toolkit from Chris O Brien, but now how?

Answer 1

There are different types of apps and where they are stored is based on there type.

Check this figure out,

Source - 1

If an app contains SharePoint components, those components are stored in a subweb of the site that is automatically created when you install the app. Apps have their own, isolated URLs, which are separate from the URL for the site that contains the app. If the app is a Provider-hosted or Windows Azure autohosted app, the app components are stored in those locations. For example, in the following diagram, App1 contains custom business logic and is stored on an external server - it is an Windows Azure autohosted app and does not store content in a subweb of the site. App2 is a SharePoint hosted app with only SharePoint components. App2's content is stored in a subweb of the site on which it is installed.

Source 2

where are they stored? Are they stored in content database where the app is installed?

If its SharePoint hosted then all of apps will be stored in app catalog, which is just a document library, therefore will reside in content db.

How to: Set up an app catalog on SharePoint

Edit for Comment

Other than these UI elements, the app for SharePoint components and content, such as lists, content types, workflows, and pages, are deployed to a different website in a special isolated domain. This fact is largely hidden from the user. The special website to which the app is deployed is called an app web. The website to which the app is installed is called the host web. Although the app web has its own isolated domain, it is in the same site collection as the host web. (One exception to this rule is when the app is installed with tenant scope. In that scenario, the app web is in the site collection of the corporate app catalog.)

Host webs, app webs, and the isolated domain

Content type, lists and other components are kept in app web which is a isolated domain in same site collection where you installed your SharePoint app. Now if you want to dig deep then these contents are stored in Content Database in which your site collection (web application) is attached to.

Answer 2

The simple answer would have been:

1. SharePoint Hosted App - a subweb of the site that is automatically created when you install the app (the ugly URL using wildcard Site Collections)

2. Auto-Hosted Apps  - in Azure Webs

3. Provider-Hosted - depends on the Provider setup - usually on other servers outside SharePoint.

Re-deploying the App would actually re-generate that URL everytime, not sure what "Update" means in that case.