Spring --- the fourth day of learning (transaction control of JDBC template + spring)

JdbcTemplate JdbcTemplate is an object provided in the spring framework, which functions as QueryRunning and is a simple encapsulation of the original Jdbc API object. The spring framework provides many template classes that are facing different database types. Operational relationship data: JdbcTempl ...

Posted by ramus on Fri, 26 Jun 2020 05:12:02 +0200

The difference between int and int(11) in Mysql

[1] The difference between int(3) and int(11) (cognitive error of thinking inertia) Here, 3 or 11 represents the specific length stored in the database, always thinking that int(3) can only store 3 numbers of length, and int(11) can only store 11 numbers of length. [2] Mysql Basics When learning M ...

Posted by mmorton on Fri, 26 Jun 2020 03:45:53 +0200

java multithreaded Callable -- segment a large list and merge the results

Code reference http://bbs.csdn.net/topics/391070227?page=1     Here is the posted Code: public void dealListWithMutiThread(){ List<Object> list = new ArrayList<Object>(10000); int index = 0; ExecutorService ex = Executors.newFixedThreadPool(5); int dealSize = 2000; List&l ...

Posted by l9pt5 on Wed, 24 Jun 2020 07:20:34 +0200

MySQL uses LOAD DATA to synchronize data to Alibaba cloud database regularly

Before  , there was a small test project that needed to synchronize some local data to Alibaba cloud database regularly. It was implemented by executing LOAD DATA with the most mechanical script. Here is a brief introduction. LOAD DATA can quickly read text file data into the table (LOAD DATA is us ...

Posted by sarun on Tue, 23 Jun 2020 04:31:16 +0200

MySQL parsing order

SQL parsing order Next, let's take a look at the past and present life of an SQL statement. First, let's look at the sample statement: SELECT DISTINCT < select_list > FROM < left_table > < join_type > JOIN < right_table > ON < join_condition > WHERE < wh ...

Posted by rlhms09 on Sun, 21 Jun 2020 04:28:16 +0200

(vi)Restrictions, table relationships, modifying table syntax, and replicating tables for P03 DB databases(vi)

Content Summary constraint condition Relationships between tables (constraints) Modify the full syntax of the table Copy Table constraint condition Default default """ # Supplement: You can specify fields when inserting data create table t1 ( id int, name varchar(16) ); insert into t1 (name, id) values ('samuel', 1); create table ...

Posted by lth2h on Fri, 19 Jun 2020 19:45:34 +0200

Account management and DDL language of mysql database

mysql database account management and DDL language 1, Database account management 1. Account creation and password modification 2. Create Zara account, password zara123, only with query permission 2, mysql four engines 3, Table management 1. Library management 1. Library creation 2. Modification ...

Posted by bryansu on Thu, 18 Jun 2020 09:48:37 +0200

4 Openstack-Ussuri-Keystone cluster deployment-centos8

The main functions of Keystone are as follows: 1 manage users and their permissions; 2. Maintain the Endpoint of OpenStack service; 3 Authentication and authentication. 4.1 configure Keystone database #Create database in any control node, the database is automatically synchronized, take controller 1 ...

Posted by Sooz719 on Thu, 18 Jun 2020 05:36:15 +0200

xtrabackup for MySQL database backup

Mysqldump is a logical backup method. Its biggest defect is that the speed of backup and recovery is slow. For a database less than 50G, this speed is acceptable. But if the database is very large, it is not suitable to use mysqldump backup again. At this time, you need a kind of easy-to-use and efficient tool. Xtrabackup is one of them, known ...

Posted by motofzr1000 on Tue, 16 Jun 2020 10:20:51 +0200

Install MySQL on Ubuntu 20.04

How to install MySQL on Ubuntu 20.04 MySQL is the most popular open source relational database management system. It's fast, easy to use, easy to expand, and part of the popular LAMP and LEMP. This guide explains how to install and protect MySQL on Ubuntu 20.04. prerequisite Make sure you are logged in as sudo user Install MySQL on Ubuntu At th ...

Posted by dorgon on Tue, 16 Jun 2020 08:57:06 +0200