How many round trips to the database server to fetch the data?

Using FoundationDB
1

I am new to Foundation DB, and have cursory understanding of RDBMS. Hence my example will use pseudo RDBMS terms to formulate my question. Sorry about that in advance.

I have following structure:

Profile { UUID, Name, …, Friends[profile_1_id, …, profile_n_id]}

When I use RDBMS, I can send a single query such as the following to get a profile, corresponding to the supplied ‘profile_id’, and its matching friends:

Select p.name, f.name from profile as p, profile as f where p.id = profile_id and f.id = p.friend_id;

This makes a single round trip to the database server to fetch the data.

How does one achieve this with FoundationDB and how many round trips does it make to the database server to fetch the profile data and the data of its friends?