Does dgraph keep one schema for both dql & graphql?

I have a dql schema with some types defined in it. My question is, does dgraph keep just one schema for both dql & graphql or separate schema for every one of those?
If dgraph keeps one schema for both, can I query the database with both dql & graphql ?

If you define a GraphQL schema, Dgraph will generate the DQL schema and save both. If you only ever provide the DQL schema, then no GraphQL will be available. You can alter the DQL schema that is generated, but some restrictions are applied to not break the GraphQL API.

Yes, as long as you have defined a GraphQL schema. You can always query/mutate in DQL even if you have not defined any schema.