@briankb-0 apps can't share the same database in Cloudron. But they can access each other's database.
For example, if you want to access Ghost's database from another app, you can go to Ghost's Web Terminal and type
env | grep MYSQL . That gives the credentials Ghost is using to connect to the database. Those credentials work from any app.
Important notes: Do not change Discourse's own database to the values above! As mentioned, apps cannot have a single database on Cloudron, each app gets it's own database.
The database credentials of an app can potentially change when you restore an app but they are retained across updates.
Other use cases: we use this to access the database of other apps via metabase. Metabase also has a way to use a "readonly" connection. Definitely use this, if it's possible.