TRUNCATE queries

[whatyouhide]

It seems like this query causes problems:

iex> Mariaex.query(conn, "TRUNCATE TABLE devices")
** (Protocol.UndefinedError) protocol Enumerable not implemented for nil
    (elixir) lib/enum.ex:1: Enumerable.impl_for!/1
    (elixir) lib/enum.ex:116: Enumerable.reduce/3
    (elixir) lib/enum.ex:1636: Enum.reduce/3
             lib/mariaex/query.ex:157: DBConnection.Query.Mariaex.Query.decode/3
             lib/db_connection.ex:799: DBConnection.decode/6
             lib/mariaex.ex:142: Mariaex.query/4

It may have to do with the commands that don't return rows? I didn't try to change those at all, but I will try to look into this myself if I have some time :).

[liveforeverx]

Thanks!

[JamesLavin]

Before laying out my similar issue (same error... different cause), I want to thank the Mariaex developers for building Mariaex!

I hit the same error but with a different use case that this solution doesn't fix because I'm trying to create a table (DDL), not truncate one. If I add query to @commands_without_rows, I'll create problems for standard queries.

I ran Ecto.Adapters.SQL.query(XYZ.Repo, ddl) where ddl is a manual create table statement (because our database team wants us to use raw SQL/DDL). My Ecto.Adapters.SQL.query call returns no results because it's a table create, not a real query, so the table gets created but the migration then blows up.

I get the same error ("(Protocol.UndefinedError) protocol Enumerable not implemented for nil") if I try

def up do
    execute "[my DDL]"
end

Other methods in the docs seem intended for use with DDL but apparently expect Ecto migration code, not raw SQL/DDL.

When I try to use Mariaex in a migration without Ecto.Adapters or execute:

    {:ok, p} = Mariaex.start_link(username: "username", password: "pw", database: "db_name")
    Mariaex.query(p, ddl)

it fails with the same error and the table doesn't get created (presumably because it's wrapped in a transaction):

18:22:46.960 [info]  == Running MyPhoenix.Repo.Migrations.CreateEligibilityRequestResponse.up/0 forward
** (Protocol.UndefinedError) protocol Enumerable not implemented for nil
    (elixir) lib/enum.ex:1: Enumerable.impl_for!/1
    (elixir) lib/enum.ex:116: Enumerable.reduce/3
    (elixir) lib/enum.ex:1636: Enum.reduce/3
    (mariaex) lib/mariaex/query.ex:157: DBConnection.Query.Mariaex.Query.decode/3
    (db_connection) lib/db_connection.ex:799: DBConnection.decode/6
    (mariaex) lib/mariaex.ex:142: Mariaex.query/4
    (stdlib) timer.erl:197: :timer.tc/3
    (ecto) lib/ecto/migration/runner.ex:26: Ecto.Migration.Runner.run/6
    (ecto) lib/ecto/migrator.ex:121: Ecto.Migrator.attempt/6
    (ecto) lib/ecto/migrator.ex:70: anonymous fn/4 in Ecto.Migrator.do_up/4
    (ecto) lib/ecto/adapters/sql.ex:508: anonymous fn/3 in Ecto.Adapters.SQL.do_transaction/3
    (db_connection) lib/db_connection.ex:1063: DBConnection.transaction_run/4
    (db_connection) lib/db_connection.ex:987: DBConnection.run_begin/3
    (db_connection) lib/db_connection.ex:667: DBConnection.transaction/3
    (ecto) lib/ecto/migrator.ex:244: anonymous fn/4 in Ecto.Migrator.migrate/4
    (elixir) lib/enum.ex:1184: Enum."-map/2-lists^map/1-0-"/2
    (ecto) lib/mix/tasks/ecto.migrate.ex:84: anonymous fn/4 in Mix.Tasks.Ecto.Migrate.run/2
    (elixir) lib/enum.ex:651: Enum."-each/2-lists^foreach/1-0-"/2
    (elixir) lib/enum.ex:651: Enum.each/2
    (mix) lib/mix/task.ex:296: Mix.Task.run_task/3

Thanks in advance for any thoughts you might have!

--James