How to query models?

[WolfDan]

For example in the repository example are a vertex called "Land", it contains the model "Person".

How do I query the person data in adition to the Land fields?

[elbow-jason]

Here is the output of Land.land_example/0 from the modules in the examples folder:

iex> Land.land_example
%DgraphEx.Examples.Land{_uid_: nil, address: "123 Maple Rd Phoenix, AZ 88888",
 city: "Phoenix", construction_year: "1982", floors: 1, geo_border: nil,
 geo_center: nil, land_size: 12, living_space: 8,
 owner: %DgraphEx.Examples.Person{_uid_: nil,
  address: "456 Maple Rd Phoenix, AZ 55555", name: "Jason Beefcake"},
 zipcode: "88888", zoning: "FAKE"}

I mutate my schema to ensure Land is in there:

iex> {:ok, _} = Repo.request mutation(schema: Land)
{:ok, %{"code" => "Success", "message" => "Done", "uids" => %{}}}

Then I do a mutation set to the land_example output:

iex> mutation(set: Land.land_example) |> DgraphEx.Repo.request
{:ok,
 %{"code" => "Success", "message" => "Done",
   "uids" => %{"land" => "0x12", "owner" => "0x13"}}}

Then I query for :land with :zipcode "88888":

iex> query(get: :land, func: eq(:zipcode, "88888"))
|> select(%Land{owner: %Person{}})
|> DgraphEx.Repo.request
|> DgraphEx.into(%Land{owner: %Person{}}, :land)

Which outputs:

%{land: [
   %DgraphEx.Examples.Land{_uid_: "0x12",
    address: "123 Maple Rd Phoenix, AZ 88888", city: "Phoenix",
    construction_year: "1982", floors: 1, geo_border: nil, geo_center: nil,
    land_size: 12, living_space: 8,
    owner: [%DgraphEx.Examples.Person{_uid_: "0x13",
      address: "456 Maple Rd Phoenix, AZ 55555", name: "Jason Beefcake"}],
    zipcode: "88888", zoning: "FAKE"}
  ]}

[elbow-jason]

@WolfDan I hope this explanation helps.

[elbow-jason]

The keys to loading nested models are the select(%Land{owner: %Person{}}) to ask dgraph for nested object data and the DgraphEx.into(%Land{owner: %Person{}}, :land) for populating the nested query into the models.

[elbow-jason]

I'm wondering if I should extend Repo.get to incorporate this behavior? What do you think?

[WolfDan]

Totally helps @elbow-jason !

Hum I think there is a problem with Repo.get and the select example that is the deply nested models, suppose this

Land contains a owner that is a user -> User contains all the lands that owns -> This request other lands and so fort...

I think is mostly a user design problem it self but I think cases like those exist, maybe another argument to except always certain fields when request all the vertex?