type user = {
  name: string;
  id: int;
  some_int64: int64;
  some_int32: int32;
  some_float: float;
  some_bool: bool;
  pet_name: string option;
  pets: string list;
  pets_array: string array;
}
[@@deriving deserialize]

type users = user list [@@deriving deserialize]

(* Start the database connection pool *)
let* db =
  let config =
    Silo_postgres.config
      ~connections:5
      ~connection_string:
        "postgresql://postgres:postgres@localhost:6432/postgres?sslmode=disabled"
  in

  match Silo_postgres.connect ~config with
  | Ok c -> Ok c
  | Error (`Msg e) -> Error e
in

(* Fetch the user and return the user to a variable *)
let* fetched_users =
  Silo_postgres.query
    db
    ~query:
      "select name, id, some_bool, pet_name, some_int64, some_int32, some_float, pets, pets as pets_array from users limit 2"
    ~deserializer:deserialize_users
in

List.iter
  (fun x ->
    Printf.printf
      "Fetching user with id %d:\nName: %s\nSome float: %f\nSome int64: %d\nSome int32: %d\n%s\n Some bool: %b\nPets: %s\nPets array: %s\n\n"
      x.id
      x.name
      x.some_float
      (Int64.to_int x.some_int64)
      (Int32.to_int x.some_int32)
      (match x.pet_name with
      | Some pn -> Printf.sprintf "Pet name: %S" pn
      | None -> "No pet")
      x.some_bool
      (String.concat ", " x.pets)
      (String.concat ", " (Array.to_list x.pets_array)))
  (Option.get fetched_users);