As an individual in and out of electronic certificate, health code belongs to the general type of one-time declaration in the whole city. Moreover, parents' health codes and children's health codes are independent, so whether they go out of the province or not, they will not affect their children's health codes.
Health codes are based on real data and can be generated by citizens or people who have returned to work through online declaration and background audit. Two-dimensional code is a personal entry and exit in electronic certificate.