Programmer Think

1. Introduction MySQL still maintained a strong database popularity growth trend in 2016. More and more customers build their applications on MySQL database, and even migrate from Oracle to MySQL. However, some customers encounter some problems in the process of using MySQL database, such as slow response time, full CPU, etc. Alibaba cloud R ...

An important function of database management system is data query. Data query should not only simply return the data stored in the database, but also filter the data according to needs and determine what format the data is displayed in. MySQL provides powerful and flexible statements to realize these operations. MySQL database uses select sta ...

Xiao Huang's Mongo chapter of self-cultivation. The course video is from the dark horse programmer Click jump There are a lot of online searches about Mongo's introduction and installation. Xiao Huang's blog is used to record how to use Mongo The example of this article comes from the situation in reality: the article comment function will ...

Based on the previous article, we only made a simple comparison between the two design ideas, without in-depth explanation of the implementation principle. In this chapter, we focus on the implementation principle of form engine system based on relational database design and the key code structure of CCBPM implementation. The form eng ...

1 Introduction What is Cache? There is temporary data in memory.Put the data frequently queried by users in the cache (memory), and users do not need to query from the disk (relational database data file) but from the cache to query the data, so as to improve the query efficiency and solve the performance problem of high concurrency sy ...

Note: the sql used in this article provides data and tables for HR users. HR user introduction view the following links. https://blog.csdn.net/weixin_45842494/article/details/122528264 1. Top-N analysis 1.1 what is Top-N analysis The Top-N query is useful when you need to display the first record or the last n records from the table ba ...

JDBC core technology Lecturer: Song Hongkang Microblog: Shang Silicon Valley - Song Hongkang Chapter 1: JDBC overview 1.1 data persistence Persistence: save data to a power down storage device for later use. In most cases, especially for enterprise applications, data persistence means saving the data in memory to the hard disk for &quot ...

Relational database and non relational database Relational database Relational database is a structured database, which is created on the basis of relational model (two-dimensional table model) and is generally record oriented. SQL statement (standard data query language) is a language based on relational database, which is used to retrie ...

typora-root-url: D:\software\dev\Typora\locales Installing Redis under Linux 1. Download the installation package! redis-6.2.4.tar.gz $ cd /home/wlk $ wget http://download.redis.io/releases/redis-6.0.6.tar.gz 2. Unzip the installation package to / opt, and you can see redis Conf file $ tar xzf redis-6.0.6.tar.gz -C /opt $ cd redis-6.0.6 ...

background As required by the company, it is now necessary to make statistics on the data of the questionnaire filled in by the user. The final presentation style is EXCEL, and the content is the options of each question filled in by the user, that is, the following table style: User ID numberQuestion 1Question 2Question 3...Question 22110000 ...