Both variants will do two separate queries.
fuelen
al2o3cr
To nitpick, this isn’t quite the same thing - this returns a User with posts preloaded, the other returns a list of Posts.
To nitpick moar, this does the same number of queries - Ecto does the preloads separately unless the query requires them to be done together explicitly with [posts: p] and a join.
Also beware blindly optimizing for “number of queries” - forcing a single query could be expensive if there are many posts and User is a wide schema, since it will include the user columns in every result row.
0
achempion
Well, to be more precise, here is full example what I need to type every time I launch new session in order to achieve something similar to ActiveRecord
alias App.Repo
alias App.UserContext.User
import Ecto.Query
User |> where(email: "email") |> preload(:posts) |> Repo.one()
and I need to do it every time I want to work with a data. If I want to explore Post I have to write one more alias, every time I start new session.
Compare it to User.find_by(email: "email").posts and it’s just a short example. In real world it quickly adds up.
User.admin.first.posts.active.published.update_all(published: false)
Imagine how much typing required with Ecto. You have to alias: User, UserContext, Post, PostContext. You have to quickly remember context names as well for a schemas.
It requires lots of effort to write something quickly in console.
On the other hand, in a project code it really isn’t an issue, because you can write much faster with code editor and most aliases are already here. Also, you need to write custom queries much less often than when you’re hacking in a console.
0
edisonywh
That’s what we are telling you though, you can have an .iex.exs that gets automatically loaded into your IEx sessions, so you don’t need to retype them every time.
1
LostKobrakai
defmodule MyApp.Explore do
defmacro __using__(_) do
quote do
alias App.Repo
alias App.UserContext.User
import Ecto.Query
end
end
end
and then you only need to call use MyApp.Explore whenever you need to do something with your data.
6