There is a need for database synchronization, as follows:
1. There is a main node and multiple sub-nodes;
2. You can add, delete, modify and check all data on the main node, and add, delete, modify and check the data belonging to the node on the sub-node (it is not required to save only the data belonging to the node);
3. The data added, deleted, modified and checked should be synchronized in time;
4. The network may be interrupted, and data may be modified during the network interruption;
5. After the network is restored, the data needs to be synchronized. If the master/sub-nodes are modified at the same time and data conflict occurs, the sub-node shall prevail;
6. To determine whether it is the same piece of data, the primary key of the data table shall prevail.
What to do, headache. . .