My project backend is using springboot, and for databases, I have SQL, MongoDB, and CouchDB as my databases.

So I created an empty project to deploy my backend project. Inside, I have to create 3 environmental variables. When deploying in railway, under my project variables, there will be 3 variables: one for SQL, MongdoDB and also CouchDB. For railway, after adding SQL and MongoDB, environmental variables for URL is automatically added, but this is not the case for CouchDB!

So for my empty project under its environmental variables, I put this: SPRINGDATASOURCEURL under my variable name and for reference I put this: jdbc:${{MySQL.MYSQL_URL}}. This is for SQL.

I put this: SPRINGDATAMONGODBURI under my variable name and for reference I put this: ${{MongoDB.MONGOURL}}/products?authSource=admin. This is for MongoDB.

Then for CouchDB, what should I set my variable name as well as for my reference, as?