DROP INDEX IF EXISTS idx_order_items_unit_id;

ALTER TABLE order_items
    DROP CONSTRAINT IF EXISTS chk_order_items_weight_single_line,
    DROP CONSTRAINT IF EXISTS chk_order_items_weight_positive;

ALTER TABLE order_items
    DROP COLUMN IF EXISTS unit_id,
    DROP COLUMN IF EXISTS weight;

ALTER TABLE products
    DROP CONSTRAINT IF EXISTS chk_products_sell_by;

ALTER TABLE products
    DROP COLUMN IF EXISTS sell_by;