How to populate an array of an object based on its indexes using RethinkDB

Hello, I'm starting to "understand" how RethinkDB works and I'm seeing that it's certainly the NoSQL database that comes closest to the logic of a SQL database without losing the optimization and benefits of NoSQL. My problem is this, imagine that I have the 2 structures below that relate students and the subjects they study:

// table matérias
"materias" : [
  { id: "m-1", nome: "Português" },
  { id: "m-2", nome: "Matemática" },
  { id: "m-3", nome: "História" },
  ...
]
// table alunos
"alunos" : [
  {id: "a-1", nome: "João", materias: ["m-1", "m-2"] },
  {id: "a-2", nome: "Mari", materias: ["m-1"] },
  {id: "a-3", nome: "José", materias: ["m-1", "m-2", "m-3"] },
  ...
]

As I found in the RethinkDB documentation , I know I can make a join for all students in a query when it is a column for an id. How should I do so that I can return an array with all students and their related subjects? I need a return like the example below:

"alunos": [
  {
    id: "a-1", 
    nome: "João", 
    materias: [
      { id: "m-1", nome: "Português" },
      { id: "m-2", nome: "Matemática" }
    ] 
  },
  {
    id: "a-2", 
    nome: "Mari", 
    materias: [
      { id: "m-1", nome: "Português" }
    ] 
  },
  {
    id: "a-1", 
    nome: "João", 
    materias: [
      { id: "m-1", nome: "Português" },
      { id: "m-2", nome: "Matemática" },
      { id: "m-3", nome: "História" }
    ] 
  }
]

I even found an example on the internet how to do this when the reference is between a unique key to a "foreign key" here .

  

The solution I'm looking for is already done using MongoDB + Mongoose but I'm trying to test the speed + the "real-time" capability it provides.