-- 0006_unit_conversion.sql (MySQL)
ALTER TABLE chemicals
    ADD COLUMN qu_factor           DOUBLE  NOT NULL DEFAULT 1.0,
    ADD COLUMN consume_unit_id      INT     DEFAULT NULL,
    ADD COLUMN consume_unit_name    VARCHAR(100) DEFAULT NULL;

ALTER TABLE chemical_usage
    ADD COLUMN unit              VARCHAR(50)   DEFAULT NULL,
    ADD COLUMN stock_amount      DOUBLE        DEFAULT NULL,
    ADD COLUMN consume_unit_id   INT           DEFAULT NULL;