Programmer Think

premise Process multiple business modules at the same time. Multiple business modules may need to transfer data to each other or need synchronous control. Two entities need to communicate with each other and must have resources that can be shared. Files on disk: -- > IO processing is slow and out of sync. Application scenario of process co ...

paging1. Background:Background 1: there are too many records returned by query, which is very inconvenient to view. How can we realize paging query?Background 2: there are four data items in the table. What if you only want to display the second and third data items?2. Implementation rulesPaging principle The so-called pagination display refer ...

Multi table query classificationCategory 1: equivalent connection vs non equivalent connection1. Equivalent connectionSELECT employees.employee_id, employees.last_name, employees.department_id, departments.department_id, departments.location_id FROM employees, departments WHERE employees.department_id = departments.department_ ...

Development tools: mysql-8.0DataGrip Data source: Chapter7 csv id,name,sales_A,sales_B,price_A,price_B E001,Zhang Tong,18,15,10,5 E002,Li Gu,12,17,10,5 E003,Sun Feng,19,20,10,5 E004,Zhao Heng,12,14,10,5 E005,Wang Na,13,11,10,5 E006,Li Wei,16,16,10,5 E007,Liu Jie,11,13,10,5 E008,Xue Li,14,18,10,5 E009,Pei Jun,11,18,10,5 (1) Arithmetic o ...

Author: fabricated belief Original text: https://segmentfault.com/a/1190000013803247 This paper introduces several main new features of 8.0 in relational database. You may already know that MySQL has provided NoSQL storage function since version 5.7, and some improvements have been made in 8.0. However, since this function is rarely used in p ...

1, Quick start 1. Check the health status of the cluster http://localhost:9200/_cat http://localhost:9200/_cat/health?v Note: v is used to require the header to be returned in the result Status value description Green - everything is good (cluster is fully functional) Yellow - all data is available but some replicas are not yet alloca ...

brief introduction The goal is to let cloud data warehouse users and developers experience the main process of building cloud native data warehouse based on AnalyticDB MySQL and DMS through simple steps. The scene will be through the links of instance opening, structure and data initialization, report development, report visualization and so o ...

First, let's talk about my version information Operating system MacOS Big Bur 11.2.2 Mysql 8.0.24 Note: I installed it through the official dmg package, not through homebrew. If it is a problem in homebrew installation, it can also be used as a reference. Current date: April 21, 2021 If you want to directly test the results, you can ju ...

4. DQL query data (most important) 4.1,DQL Data Query Language All query operations use it to SELECT It can do simple query and complex query~ The core language and the most important statement in the database Most frequently used statements SELECT statement syntax SELECT [ALL | DISTINCT | DISTINCTROW ] [HIGH_PRIORITY] [STRAIGHT_ ...

APIJSAON (I: Introduction)backgroundDue to various wonderful abbreviations, chaotic naming, outdated documents, out of sync with interfaces, unstable or arbitrary changes of data types, hundreds or even thousands of chaotic status codes, all kinds of wrangling between the front end and the back end, cumbersome whole development process, long de ...