Run the migrations you define against the agent database, and read their history.

A migration is a module that uses Ecto.Migration, defined with the define tool like any other. Your beamlet files it with the next version number; it is pending until you run it from here. The loop is: define the migration, migrate/0, then define the Ecto.Schema module for the table it created and use it through Host.Repo.

defmodule Shopping.CreateLists do
  @moduledoc "Creates the shopping lists table."
  use Ecto.Migration

  def change do
    create table(:shopping_lists) do
      add :name, :string, null: false
      timestamps type: :utc_datetime
    end
  end
end

Then, from eval: Host.Migrator.migrate().

migrate/0 and rollback/0 change the database, print what they applied or undid, and return :ok; print_migrations/0 prints the history, version, module, applied or pending, and returns :ok. A failure raises with a teaching message. Inside a migration, query by table name and call Host.Repo by name after flush(); do not reference schema modules, which change while a migration is frozen history.

To change a migration that has run, rollback/0, replace it and migrate/0 again. SQLite cannot change a column's type or drop a constraint: create a new table, copy the rows with an insert from a select, drop the old table and rename the new one.