Rails - Keep a table out of structure.sql during migrations

Question

It is straightforward to ignore tables when your schema format is :ruby, but is there a way to do it when your schema format is :sql?

Ideally something like this in environment.rb:

ActiveRecord::SQLDumper.ignore_tables = ['table_name']

After a quick perusal through the AR source code it looks unpromising.

Answer 1

There is currently no way to do this, when the schema format is set to :sql, Rails doesn't go through the regular SchemaDumper but instead uses the tasks in ActiveRecord::Tasks::PostgreSQLDatabaseTasks to do the dump, check it out here.

The code is quite straightforward. I came up with a simple patch for ActiveRecord that should work as expected. It relies on setting the tables to ignore in your database.yml file. It basically adds the following code:

ignore_tables = configuration['ignore_tables']
unless ignore_tables.blank?
  args += ignore_tables.split(',').map do |table|
    "-T #{table}"
  end
end

I just submitted a pull request to rails with those changes. In case you'd want to test it.