Programmer Group

1) What is a federated index? A federated index refers to indexing multiple columns in a table. In other words, multiple columns on the table add up to form an index for fast query. 2) How do I use federated indexes? First, add an index to the table Add to table when creating table: CREATE TABLE t( a int, b int, primary key(a), ...

Java learning punch in: on the 31st and 2nd day [complete the socket chat room construction project] Java cultivation program (punch in day 31 and day 2) Content management: implementation of Sockect chat room The Java interface uses various components. Don't worry about what you don't know about this part. It's OK to master one at p ...

36-Blog Site Database-Blog Comment Information Data Operation Item Description Nowadays, micro-blog and blog publishing information have become the main information publishing and dissemination system. How to manage these data, this project mainly operates on the blog information table and commentary table in the blog website. Blog site data ...

Python 3 implementation and improvement of Apriori algorithm Code reference machine learning practice The improved methods are partly from data mining: concepts and technologies, and partly from https://blog.csdn.net/weixin_30702887/article/details/98992919 I summarize and implement here, and record my learning of Apriori algorithm First ...

Indexes Data structure to help mysql obtain data efficiently Disadvantages: it reduces the efficiency of updating tables and increases disk overhead. B tree and B + tree The number of B's in the m-fork contains at most m-1 keys per node, while the number of B's + contains at most M keys The leaf node of the B + tree stores all key informati ...

Today's young people can really play, more and more new things come out, and more and more fun things are popular. It's like the blind box of the recent fire stall. Seriously, I didn't know what a blind box was before. In front of me, a fan asked me to develop a small blind box program. Therefore, I went to the stall and bought some bl ...

preface This blog follows the content of the previous blog and supplements the DQL language. It mainly talks about the sorting query, common functions and grouping query in the DQL language. These three pieces of content mainly reflect the sorting and grouping query functions of MySQL. Here is the link to the blog that knows MySQL for the ...

Note source: Dark horse programmers have a comprehensive and in-depth study of Java Concurrent Programming and a full set of tutorials of JUC concurrent programming Note source: AC_Jobim JUC concurrent programming tutorial Some personal opinions are attached. If there are mistakes, please correct them! 1, ThreadLocal details Good b ...

What is distributed caching? In the original application, the cache is usually stored in the JVM of the local application. However, with the trend of project microservicing, after the project is reconstructed in the way of microservice, the cache should be managed and stored by a separate server and deployed in different physical areas to achi ...

Vue like rendering and database of wechat applet Front row idea: the content of this article includes: Class Vue rendering → wxss.js.wxml → cloud development → cloud development usage (storage and database) → database initialization → insert → json file import → query → life cycle Front row tips: Th ...