Combined with customs commodity classification. Then imitate and design a set of coding principles.

This eliminates the problem of how to classify these goods and how to classify them. The design of coding principle combines the length requirements of the field.

Personal suggestion, use pure numbers to facilitate later input. You can also match letters. But it is best to put it on the head or tail.

Remember to use fewer special symbols. Not conducive to output and input. The symbol "-"is located on the keyboard and can also be used to distinguish the version of the product number.

For example, the number "1" in our company starts with finished products, and the number "3" starts with purchased parts and materials.