How to do this migration if table is already on production?

Questions / Help
,
1

I have a migration name user id as default.


create table(:user) do
      add(:name, :string, null: false)
      timestamps()
end

But I want to rename this table to something like this

table(:user, primary_key: false)

and also if I want to add the new field.

add :id, :uuid, primary_key: true

The data is already on production. So how can I do this efficiently?

2

Perhaps something like this

def change do
  alter table(:user) do
    add(:id, :bigserial)
  end

  flush()

  alter table(:user) do
    modify(:name, primary_key: false)
    modify(:id, primary_key: true)
  end
end
3

But then it’s giving me this error

(Postgrex.Error) ERROR 42701 (duplicate_column) column “id” of relation “user” already exists

4

is this name referring to table user?

5

Wouldn’t you need to drop the PK first then add the second one?

6

Ok, so you already have a migration which already puts an ID column by default.

Do you need to change it to :uuid?

If so you need to create a new column with that type, and then drop the old id column, and add the new uuid-column as primary key. I don’t know if uuid columns will auto-populate

7

Yeah I need to change the primary key as uuid. But if I drop it in my local and run it again and if it worked. Then what production there I can’t drop the table, right?

8

how do I do this?

9

I think have a look at the ecto migration documentation a bit and you would be able to answer your own question very quickly