one database of user balance, one database of order table, one database of fund details users use balance to place orders, how to ensure that no more orders will be placed and the data are consistent in the case of large concurrency ...
recently, I have been studying the scheme of sub-database and sub-database. I don t have much experience. If you have any questions, I will ask you for advice. for example, an order table with fields: placing an order for id, goods, id, store, id, iss...