text: -- migrate:up
  CREATE TABLE IF NOT EXISTS purchase_details (
      purchase_code UUID NOT NULL,
      material_code UUID NOT NULL,
      quantity int4 NOT NULL DEFAULT 0,
      price NUMERIC(12, 2) NOT NULL DEFAULT 0.00,
      FOREIGN KEY (purchase_code) REFERENCES purchases (expense_code),
      FOREIGN KEY (material_code) REFERENCES materials (code),
      PRIMARY KEY (purchase_code, material_code)
  );
  -- migrate:down
  DROP TABLE IF EXISTS purchase_details;