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Project Description: in the wechat applet, log in and verify with the spring boot operation database. I use spring boot to integrate the mybatis plus and mysql operation database 1. Preparation before development 1.1 prior knowledge java Foundation SpringBoot simple Basics 1.2 environmental parameters Development tools: IDEA Basic environm ...

DBUtils is a module of Python used to implement database connection pool, and allows thread safe packaging of non thread safe database interface. Two modes of connection: Create a connection for each thread. Even if the thread calls the close method, it will not close. It just puts the connection back into the connec ...

Note: this post is based on Basic query example of database (1)1. Query all f ﹣ name values corresponding to each s ﹣ ID in fruits table #Compact in groups mysql> select s_id,group_concat(f_name) as name from fruits group by s_id having count(f_name) > 1; 2. How many rows are counted for the same s ﹐ ID value? mysql> select s_id,co ...

Environmental Science macOS 10.13.3 docker 17.12.0-ce mysql container information CONTAINER ID: 478bbac9137b IMAGE: mysql:5.7.21 PORTS: 0.0.0.0:3306->3306/tcp NAMES: mysql.5.7.21.plus Preface Currently, you use the MySQL container of docker to use mysql. As long as you run the container, you can use the local t ...

mysql's collation roughly means character sorting. First, characters are inherently size-insensitive, so a rule of character order is required for character >, =, <operations.collation does this either by setting the character order of a table or by setting the character order of a field separately.A character ty ...

1. Log in with root admin@lnxServer:~$ mysql -uroot -p123456   Warning: Using a password on the command line interface can be insecure.   Welcome to the MySQL monitor.  Commands end with ; or \g.   Your MySQL connection id is 154   Server version: 5.6.19-0ubuntu0.14.04.1 (Ubuntu)      Copyright (c) 2000, 2014, Oracle and/or i ...

Recently, when dealing with a table splitting problem, we need to create a stored procedure for the program to automatically split tables. We need to ensure that all table structures, constraints, indexes, etc. are consistent. In addition, views, stored procedures, permissions, etc. are not considered temporarily. In Mysql, the procedure of cre ...

In most applications, the group concat function is usually used for row column conversion. In fact, the group concat function also has a very important function, that is, sorting within groups. Group ABCD concat full syntax: Group concat ([distinct] field to connect [Order BY ASC/DESC sort field] [Separator 'Separator']) 1. Basic usage: 1 ...

CentOS 6.5, MySQL multiple instances (in fact, the same principle applies to a single instance) 1, Problem description [root@www ~]# /data/3308/mysql start Starting MySQL... [root@www ~]# ps -A|grep mysql [root@www ~]# Start mysql database, and there is no result by checking the process. 2, Problem solving Check the mysql error log. Th ...

Oracle update trigger Go straight one without more words DROP TRIGGER kfzt_afterupdate_dlzt; create or replace trigger kfzt_afterupdate_dlzt AFTER UPDATE ON jg_kfzt FOR EACH ROW BEGIN -- The update timeout is equal to the heartbeat time plus30Minute;Online time equals heartbeat time minus minutes of login time; ...