How do I disable the migrations feature in a Rails app?

Question

Background

We engineer database models and application models separately (RDMBS architects vs OOP engineers). From what I've seen regarding Rails versus domain/key normal form, Rails migrations cannot easily duplicate all the features of a well-designed enterprise RDBMS (if at all) so we don't migrate and instead use other tools to build databases (nevermind the problem of object-relational impedance mismatch). Data integrity and DB performance are too valuable to us to risk RDBMS model changes by any developer.

Question

For whatever reason, we now have a Rails app that has made damaging DB changes through migrations. How do I cleanly disable this feature in an existing Rails application?

I have my theories but I want to know what the world thinks.

Answer 1

This came up again when testing finally came to the front. Thus, I took deeper look and came up with the following thanks, in part, to the comments left on the question. This removes all rake DB capabilities and tests still run fine. (In case anyone is wondering, we clone the test DB from elsewhere when we need to refresh it.)

Add this to the Rakefile:

# Disable DB migrations, DB test preparing, etc.
Rake::Task.tasks.each do |t|
    if t.name[0,3] == "db:"
        t.clear
        t.add_description("!!! Disabled in favor of enterprise design at Acme.")
    end
end

Comment out all the fixtures in test/test_helper.rb:

#fixtures :all

Answer 2

In juanitogan's answer, we disable all db tasks. In my case I still wanted to be able to run db:schema:load. Here the slightly modified code for the Rakefile:

# Disable migrations
Rake::Task.tasks.each do |t|
  if t.name.start_with?("db:migrate")
    t.clear
    t.add_description("Disabled; Load the data model via db:schema:load.")
    t.actions << proc { puts "Migrations ignored. That's ok. Please see README."}
  end
end

When creating models, you can append the --no-migration option like so: rails g model abc --no-migration