Unable to read inserted(?) rows with SQLITE, ECTO

Questions / Help
,
1

I am using a CSV dataset in SQLite to seed. It seems that I can insert data but I can’t read it ! Something obvious must be missing but I just don’t see.

The table looks like this:

def create_table(conn, table) do
    Exqlite.Sqlite3.execute(
      conn,
      "CREATE TABLE IF NOT EXISTS #{table} (
        id integer primary key,
        ident string,
        elevation_ft string,
        type string,
        name string,...

I also have a schema and a Repo.

defmodule Airport do
  use Ecto.Schema
  import Ecto.Changeset
  @headers headers
  @columns Enum.map(@headers, &String.to_atom/1)

  schema "csv" do
    Enum.each(@columns, &field(&1, :string))
    #timestamps()
  end

  def changeset(attrs \\ %{}) do
    %Airport{}
    |> cast(attrs, @columns)
    |> validate_required(@columns -- [:iata_code])
  end
end

I check that the fields are :ok

Airport.__schema__(:fields)
[:id, :ident, :type, :name, :elevation_ft...]

Now it seems that I can insert (?) a row:

l = %{
      coordinates: "-74.93360137939453, 40.07080078125",
      elevation_ft: "11",
      gps_code: "00A",
      ...
}
|> Airport.changeset()
|> Repo.insert()

which returns:

[debug] QUERY OK db=0.9ms idle=1248.3ms
INSERT INTO "csv" (coordinates","elevation_ft","gps_code....

{:ok,
 %Airport{
   __meta__: #Ecto.Schema.Metadata<:loaded, "csv">,
   id: 57424,
   ident: "00A",....

but I can’t read it !??

Repo.get(Airport, 1)
** (ArgumentError) cannot load `11` as type :string for field :elevation_ft in %Airport{__meta__:

It seems that I can insert my whole file, but I can’t read it either:

Repo.aggregate(Airport, :count)
57342

Seems good, but:

Repo.all(Airport)
** (ArgumentError) cannot load `11` as type :string for field :elevation_ft in 
%Airport{__meta__: #Ecto.Schema.Metadata<:loaded, "csv">, id: nil, ident: nil, type: nil, name: nil, elevation_ft: nil,
...
1 Like
2

Have you tried updating your Ecto schema field type for :elevation_ft? It looks like it is failing when trying to coerce an integer from SQLite into a string in Elixir.

Edit: check your CSV - I can’t tell from the sample error whether :elevation_ft is integer or float.

Edit2: From what I understand, SQLite is pretty slack about field types - they are advisory only. From my reading of it, you need to be pretty disciplined to ensure your Ecto schema definition matches what’s actually in the table. When I’ve used SQLite in Elixir I’ve bypassed Ecto and put some bespoke type-casting code in place as I had no idea what would be coming in, but it somehow had to end up a number for some charts.

1 Like
3

ok, I knew it was something stupid. The correct type is TEXT, not “STRING” with SQLite. I wasn’t running a migration, I was creating the table via SQL! What is misleading is that errors are inserted as “nil” values.

"CREATE TABLE IF NOT EXISTS #{table} (
        id integer primary key,
        ident TEXT,