Provides some helper functions for easy batching of Ecto assocations
These functions all make use of the batch plugin found in Absinthe, they're merely just some helpful ways to use this plugin in the context of simple ecto associations.
First specify the repo you're going to use:
use Absinthe.Ecto, repo: MyApp.Repo
Then, supposing you have some ecto associations as in this example schema:
defmodule MyApp.Post do
use Ecto.Schema
schema "posts" do
belongs_to :author, MyApp.User
has_many :comments, MyApp.Comment
field :name, :string
field :body, :string
end
end
Your graphql post object might look like:
object :post do
field :author, :user, resolve: assoc(:author)
field :comments, list_of(:comment), resolve: assoc(:comments)
field :title, :string
field :body, :string
end
Now, queries which get the author or comments of many posts will result in just 1 call to the database for each!
The assoc
macro just builds a resolution function which calls ecto_batch/4
.
See the ecto_batch/4
function for how to do this from within a regular
resolution function.