[Proposal] Add "into" keyword to ecto query expression

[Yusuf]

Hello everyone,

This is my first time posting, please excuse me if I did something wrong :)

I am writing a query like below,

query =
    from u in User,
    where: u.id in ^user_ids,
    select: {u.id, u}

data =
    query
    |> Repo.all()
    |> Enum.into(%{})

As follows, Does it make sense to add the "into" keyword into to this query?

query =
    from u in User,
    where: u.id in ^user_ids,
    select: {u.id, u},
    into: %{}

data =
    query
    |> Repo.all()


I would like your thoughts on this one.

[Andrey Yugai]

I wouldn't claim this is a good idea because `into` in your example looks like leakage of app logic into DB level. If you're only ought to create user id - user map, it is pretty easy to do in Elixir from just a list of users. If you concerned about memory/time, you could try streaming from repo. If your data is inevitably key value table, then maybe you better off using JSONB column for storing maps, or even exploring document DBs.

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[Daniel Kukuła]

remove the select to just have the user schema returned and then:

Repo.all |> Map.new(&{&1.id, &1})

[Yusuf]

Thank you for your answers. 

You are right. 

31 Ağustos 2022 Çarşamba tarihinde saat 19:54:22 UTC+3 itibarıyla danie...@gmail.com şunları yazdı:

[Greg Rychlewski]

Instead of `:into` it might be possible to allow selecting maps where the keys are column values. It could be worth exploring that idea.