As can be seen from the code structure of commodity bar code, the distribution of commodity item codes is complete, strict and systematic. The compilation of commodity project codes uniformly distributed and used by enterprises should follow the principles of uniqueness, permanence and meaninglessness.

I. Uniqueness

Uniqueness is one of the elements for enterprises to design and use commodity bar codes, that is, a basic consumption unit can only be uniquely identified, that is, "one object and one yard". The "one thing" mentioned here does not refer to a commodity, but to every commodity that can be distinguished from other commodities. Enterprises should give different commodity item codes according to different specifications, models, trademarks, brands, shapes, weights, quantities, formulas, prices and colors. This is because in the commodity bar code system, the difference between commodity and commodity price is identified by different bar codes, and the automatic identification system will regard it as the same commodity, which will either cause economic losses to customers or sellers; At the same time, it also led to manufacturers and manufacturers can not accurately grasp the sales information of goods, making the store automation system meaningless. On the other hand, if the same commodity has several bar codes corresponding to it, the automatic identification system will treat it as several different commodities, which will not only greatly increase the workload of data processing, but also cause confusion in management.

Second, persistence.

Permanence means that once the commodity item code is determined, it will not change until the product is discontinued.

Third, it is meaningless.

Meaningless means that the commodity item code only plays the role of uniquely identifying the commodity. In order to ensure that the bar code has enough capacity to meet the needs of the development of commodity economy and the frequent upgrading of commodities, it is best to adopt meaningless serial codes or serial serial serial codes. Some enterprises have fewer products and slow upgrading, so they can also be given certain classification significance when assigning commodity project codes.