Ruby Object Mapper - How to change the default order field in a Create command?

Question

I am current working on a project that I want to use Ruby Object Mapper with an existing sql database. I am running into a problem when I execute a create command, the returned result seems to sort by table_name.id by default. This is a problem because the existing tables that I am working with has a primary key named other than id, and it causes a unknown column 'id' exception.

I just wonder if there is any possible way to change the default order column?

Answer 1

Just got answer from Github:

This is an issue related with rom-sql (https://github.com/rom-rb/rom-sql/blob/master/lib/rom/sql/relation.rb#L39).

The solution is to declare your dataset explicitly in the relation of your command. Try something like this:

class MyRelation < ROM::Relation[:sql]
  dataset { order(:my_column) }
end

https://github.com/rom-rb/rom/issues/339#issuecomment-193904733

Update:

Alternatively you can also set that in the container definition using :macros:

rom_container = ROM.container(:sql, 'mysql2://root@localhost/db_name') do |rom|
  rom.use :macros

  rom.relation(:users) do |r|
    r.primary_key :my_column
    r.dataset { order(:my_column) }
  end
end