Database bind variables are only available during an app’s deployment and run times. We create app databases at build time, meaning they are bind variables not accessible during the app’s build phase.
If you need your database available at build time, you can manually inject the connection details of an existing database into the build instead of using bind variables. To do this, create an environment variable in your app’s Settings with your database’s connection string. You cannot use this solution with App Platform’s Developer Databases.