Kotlin Flow (data flow) on Android, from shallow to deep

In coroutines, Flow is a type that emits multiple values sequentially, rather than a suspending function that returns a single value. For example, you can use Flow to receive real-time updates from a database. Dataflows are built on top of coroutines and can provide multiple values. Flow is conceptually a data flow that can be […]

[SQL statement optimization]

Article directory SQL statement optimization ①Insert data ☆insert ☆Insert data in bulk ②Primary key optimization ☆Data organization ☆page split ☆page merge ☆Primary key design principles ③**order by optimization** ④ group by optimization ⑤ limit optimization ⑥ count optimization ⑦update optimization SQL statement optimization ①Insert data ☆insert 1) Insert data in batches If you insert multiple […]

Explore why in JS, you need to add in front of the function!

Dachang Technology Advanced Front-End Node Advanced Click on the top Programmer Growth Guide, pay attention to the official account Reply 1, join the advanced Node exchange group Introduction We basically know that there are two ways to declare a function function msg(){alert(‘msg’);}//declarative definition function Copy Code var msg = function(){alert(‘msg’);}//function assignment expression defines function Copy […]

Data Structure Linear Table Application (C++)

1. Merge linear tables (A∪B, order not required) ① Calculate the lengths of A and B ②Starting from the first data element in LB, loop n times to perform the following operations: Find the i (1≤i≤n) data element from LB and assign it to e; Find element e in LA, if it does not exist, […]

Please create tables S, P, J, SPJ, and perform related queries

Article directory database display Create table statement and related data Answers to textbook exercises Database display Create table statement and related data List J SET NAMES utf8mb4; SET FOREIGN_KEY_CHECKS = 0; — —————————- — Table structure for j — —————————- DROP TABLE IF EXISTS `j`; CREATE TABLE `j` ( `JNO` char(3) CHARACTER SET utf8mb4 COLLATE […]

Spring Boot integrates RocketMQ to realize normal, delay, transaction message sending and receiving, PULL consumption mode and enable ACL | Spring Cloud 30

1. Foreword In the previous section, we had a basic understanding of RocketMQ through the following chapters: docker-compose builds RocketMQ 5.1.0 cluster (dual master and dual slave mode) | Spring Cloud 28 docker-compose build RocketMQ 5.1.0 cluster to enable ACL permission control | Spring Cloud 29 Now let’s formally study the integration of RocketMQ in […]