I have a time table that stores a time zone. I want to ensure that the value entered is a valid time zone. To do that I have a check constraint that attempts to cast the current time to the submitted tz. When using real tzs like “America/New_York” everything works expected. When I use the fake, “New_York”, tz insert fails as expected but Ecto.Changeset.check_constraint/3 fails to catch the resulting Postgrex.Error.

# Migration 
def change do
  create table(:times) do
    add :time_zone, :string, null: false
  end

  create constraint(:times, :valid_time_zone, check: "now() at time zone time_zone is not null")
end

# Schema
defmodule MyApp.Time do
  use Ecto.Schema
  import Ecto.Changeset

  schema "times" do
    field :time_zone, :string
  end

  def changeset(time, attrs) do
    time
    |> cast(attrs, [:time_zone])
    |> validate_required([:time_zone])
    |> check_constraint(:time_zone, name: :valid_time_zone)
  end
end

# Console Error
** (Postgrex.Error) ERROR 22023 (invalid_parameter_value) time zone "New_York" not recognized
    (ecto_sql 3.11.1) lib/ecto/adapters/sql.ex:1054: Ecto.Adapters.SQL.raise_sql_call_error/1
    (ecto 3.11.2) lib/ecto/repo/schema.ex:775: Ecto.Repo.Schema.apply/4
    (ecto 3.11.2) lib/ecto/repo/schema.ex:377: anonymous fn/15 in Ecto.Repo.Schema.do_insert/4
    (ecto 3.11.2) lib/ecto/repo/schema.ex:1033: anonymous fn/3 in Ecto.Repo.Schema.wrap_in_transaction/6
    (ecto_sql 3.11.1) lib/ecto/adapters/sql.ex:1358: anonymous fn/3 in Ecto.Adapters.SQL.checkout_or_transaction/4
    (db_connection 2.6.0) lib/db_connection.ex:1710: DBConnection.run_transaction/4
    iex:3: (file)

Why does the check constraint fail here?
How should I handle raw raw Postgrex errors (using try?)
Is there a better way to test for timezone in a check constraint?