blog/traveling-time-with-postgres-range-columns/

state_tax_migration.rb

class AddStateTaxes < ActiveRecord::Migration[7.0]
  def change
    create_table :state_taxes do |t|
      t.integer :state_id, null: false
      t.string :tax_type, null: false
      t.decimal :rate, null: false
      t.daterange :effective_range, null: false
      t.tsrange :system_range, null: false
    end

    reversible do |direction|
      direction.up do
        execute <<-SQL
          CREATE EXTENSION IF NOT EXISTS btree_gist;
          ALTER TABLE state_taxes
          ADD CONSTRAINT prevent_overlapping_state_taxes EXCLUDE USING gist
          (
            state_id WITH =,
            tax_type WITH =,
            effective_range WITH &&,
            system_range WITH &&
          );
        SQL
      end

      direction.down do
        execute <<-SQL
          ALTER TABLE state_taxes
          DROP CONSTRAINT IF EXISTS prevent_overlapping_state_taxes;
        SQL
      end
    end
  end
end