Programmer Group

Sometimes we need to save a lot of data, which is time-sensitive, such as some logs. After a period of time, the existence of these data is not significant, and in addition to taking up a lot of hard disk space, it may make data queries slow.This data needs to be cleaned up regularly.We can cope with ...

Adding fields to a table of ten million or more levels in MySQL has always been a headache. In this case, how to deal with it? This paper uses three common scenarios to illustrate the case. 1. Environmental preparation Database version: 5.7.25-28 (Percona branch) Server configuration: three centos 7 virtual machines with 2CPU 2G memory Database ...

Introduction of master and slave What is master-slave? MySQL master-slave replication is one of its most important functions. Master-slave replication refers to that one server acts as the master database server and another or more servers act as the slave database server, and the data in the master ...

SELECT pf1001.attrId, attrCode, attrName, (case pf1001.scopeType when '04' THEN CONCAT('product-',(select productName from pf1003 where productId= pf1001.scopeId)) WHEN '03' THEN CONCAT('Product line-',(select productLineName from pf1004 where productLineId= pf1001.scopeId)) WHEN '02' THEN CONCAT( ...

Hunt Framework is a full stack Web framework developed in D language, similar to Laravel / SpringBoot / Django, etc., which enables D language developers to create projects quickly. The built-in super multi business specifications are convenient for developers to use out of the box, and convenient for managers to review project code more easily ...

Finish MySQL in half a day (all) Finish MySQL (all) 1 in half a day The blogger uses MySQL version 8.0, and the storage engine is InnoDB. We don't explain InnoDB in detail here. If necessary, we recommend you to know This article Blog (or Baidu) https://www.jianshu.com/p/519fd7747137 3A. Add, delete, ...

Recently, the task is relatively light, and I have free time to learn learning technology, so I come to study how to realize the separation of reading and writing. Here we use blog to record the process. On the one hand, it can be viewed in the future, and on the other hand, it can also be shared with you (most of the information on the Interne ...

Simple Edition Create a test table Create the corresponding JavaBean Create mybatis configuration file and sql mapping file test MyBatis operation database Create MyBatis global profile The global configuration file of MyBatis contains settings and properties information, such as database connection pool information, which affect MyBatis' ...

Previous writing is too messy, turn it out and reorganize it Small Catalog Series: (1) Getting started with MySQL is not a big problem https://segmentfault.com/a/11... (1) introducing constraints (1) Where do constraints occur? To explain constraints, you need to know where and why constraints are used. The SQL language completes the definitio ...

Title: Article content output source: Lago education Java high salary training camp. This article is part of the notes in the MySQL learning course. This post explains in detail how to build MySQL with high availability and provides a solution to solve the problem that the common master-slave replicat ...