Seeding the Database from a CSV file in Phoenix/Elixir

Question

When I try to run: mix run priv/repo/seeds.exs, I have a problem: (FunctionClauseError) no function clause matching in anonymous fn/1 in :elixir_compiler_1.__FILE__/1 The following arguments were given to anonymous fn/1 in :elixir_compiler_1.__FILE__/1:

This is my seeds.exs file:

alias FlightsList.Repo
alias FlightsList.Management.Flights

File.stream!("C:/Users/vukap/phx_projects/flights_list/priv/repo/flights.csv")
|> Stream.drop(1)
|> CSV.decode(headers: [:Id, :Origin, :Destination, :DepartureDate, :DepartureTime, :ArrivalDate, :ArrivalTime, :Number])
|> Enum.each(fn {:ok, map} ->
  Flights.changeset(
    %Flights{},
    %{Id: String.to_integer(map[:Id]), Origin: map[:Origin], Destination: map[:Destination], DepartureDate: String.to_integer(map[:DepartureDate]), DepartureTime: String.to_integer(map[:DepartureTime]), ArrivalDate: String.to_integer(map[:ArrivalDate]), ArrivalTime: String.to_integer(map[:ArrivalTime]), Number: map[:Number]})
  |> Repo.insert!()
end)

How can I fix it?

Answer 1

I guess you are missing a separator in CSV.decode function, here is an example of how I do it, you can call stream_csv in seed file.

  def store_it(row) do
    {:ok, result} = row

    %Segments{
      id: result.id,
      name: result.name
    } |> Repo.insert!
  end

  def stream_csv do
    Path.expand("~/Project/segmments.csv")
    |> File.stream!
    |> CSV.decode(separator: ?;, headers: [:id, :name])
    |> Enum.each(&store_it/1)
  end