How to remove primary key column in ecto elixir

Question

When I use remove key in migration it was not delete the constraint in the table it only delete column name. Please help how can i create for that migration file.

defmodule ControlCenter.Repo.Migrations.CreateRemedyTable do
use Ecto.Migration

def up do
  create table(:remedy, primary_key: false) do
     add :remedy_code, :string, primary_key: true
     add :description, :string
     add :cause_code, :string, primary_key: true

  end
 end

 def down do
    drop table(:remedy)
 end
end

I want to remove cause_code from the table

Answer 1

If you want to remove the column, you'll need to alter the table to remove the column after modifying it to not be part of the composite primary key:

alter table("remedy") do
  modify(:cause_code, primary_key: false)
  remove(:cause_code)
end

If you're deleting it for this migration, add it in the up function. If you're deleting it as a one-off, you can import Ecto.Query and do the above in iex -S mix . Keep in mind, there's not a good solution for migrating back down with a column removal, especially when it was part of a composite key.