elixir - 如何在 Elixir Repo.Transaction 中添加 COPY FROM STDIN

Question

我正在试验 Elixir Ecto，现在我需要在我的代码中实现 COPY FROM STDIN。我在 github 上的 postgrex.ex 中找到了示例:

Postgrex.transaction(pid, fn(conn) ->
  query = Postgrex.prepare!(conn, "", "COPY posts FROM STDIN",[copy_data:true])
  stream = Postgrex.stream(conn, query, [])
  Enum.into(File.stream!("posts"), stream)
end)

如何根据需要转换它。我必须通过什么 pid？

Repo.transaction fn ->
  query = "some query"
  Ecto.Adapters.SQL.query!(Repo, query, [])
  #copy from stdin, how??
end

Answer 1

根据 this post由 James Fish在 Elixir 论坛上，应该可以:

It is possible to run a COPY FROM STDIN using Ecto.Adapters.SQL.query!/4 but can't use a collectable/stream:

Ecto.Adapters.SQL.query!(Repo, "COPY posts FROM STDIN",
[data_as_(final)_parameter], [copy_data: true])

..和:

From Ecto 2.1 the above no longer works. Instead must use built in streams:

stream = Ecto.Adapters.SQL.stream(TestRepo, "COPY posts FROM STDIN")
TestRepo.transaction(fn -> Enum.into(data_enum, stream) end)