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...
convert the level of an inner-table number according to the format. The format is defined as follows (matching the last digits): Type 1 AAAAA (5 hyphens) ABCDEF Type 2 AAAA (4 hyphens, excluding 4) ABCDE Class 3 AAA (3 hyphens, excluding 4) ABCD Cla...
class Models { async setModels(app){ const sequelize = require( sequelize ) const files = await this.readModels() global.Models = {} global.Models._Op = sequelize.Op app.context.Models = {} app.co...
Hello, everyone. I just learned neural network. I want to do a regression experiment to test whether neural networks can learn this special case. This is a simple experiment, training data is randomly generated 10000 pieces of data, each data feature ve...
import java.util.ArrayList; import java.util.HashMap; import java.util.Iterator; import java.util.Map; public class Reminder { public static void main(String args[]) { ArrayList<String> arrStr = new ArrayList<>(); Map<...
df = pd.DataFrame({ key1 : [ a , a , a , b , b ], key2 : [ c , d , c , c , d ], data : [1,10,2,3,30]}) >>> df key1 key2 data 0 a c 1 1 a d 10 2 a c 2 3 b c 3 4 ...