User information table: user_profile
Device ID (device_id)
Post quantity field (question_cnt)
Answer quantity field (answer_cnt)
iddevice_idgenderageuniversitygpaactive_days_within_30question_cntanswer_cnt12138male21Peking University3.4721223214maleNULLFudan University4155253654 ...
Posted by FezEvils on Sat, 26 Feb 2022 09:24:04 +0100
Absrtact: paging query is required to turn the page of posts, and paging query is also required to search goods. When there are tens of millions or hundreds of millions of data, how can we quickly pull the full amount of data?
This article is shared from Huawei cloud community< Paging query for large data volume performance optimization &g ...
Posted by summerpewp on Sat, 26 Feb 2022 04:36:27 +0100
The latest MySQL tutorial is easy to understand
javaEE: Enterprise java Web Development Front end (page: display, data!) Background (connection point: connect database JDBC, link the front end (control, control view jump, and transfer data to the front end)) Database (save data, Txt, Excel, word)
1.1 why learn database?
1. Job demand 2. In t ...
Posted by rachelkoh on Fri, 25 Feb 2022 17:44:24 +0100
Introduction and description
Four traditional mainstream databases:
Oracle MySQL SqlServer DB2
Non relational database: Redis MongoDB
The mainstream database is relational database: there is an association relationship between tables
When we say install database, we mean install database service
When creating a database, it refers t ...
Posted by rockobop on Fri, 25 Feb 2022 14:05:34 +0100
Database: add, delete, modify and query commands for databases and tables
Connect to mysql To connect to the MySQL server: mysql -u root -p (Note: my user name is root), and then enter the password to connect again
Create a database and set the encoding format to utf8
create database if not exists Library nam ...
Posted by maniac1aw on Fri, 25 Feb 2022 12:50:00 +0100
There are five ways to obtain database connection:
Method 5 [final version] only this one can be practiced (doge):
Put the basic information into a configuration file.
Benefits of mode 5:
1. Realize the separation of data and code, and realize decoupling
2. If you need to modify the configuration file information, you ...
Posted by saraadmin on Fri, 25 Feb 2022 07:44:41 +0100
What is binlog
There are various types of logs in mysql, which record mysql, including startup, operation, connection, change and other operations, and binlog is the most important log. It records the changes of all MySQL data and stores it on disk in binary form
binlg records all table structure changes (CREATE, ALTER TABLE... ...
Posted by coder9 on Thu, 24 Feb 2022 16:59:59 +0100
1, MHA overview
1.1 what is MHA
MHA (MasterHigh Availability) is a set of excellent software for failover and master-slave replication in MySQL high availability environment. The emergence of MHA is to solve the problem of MySQL single point. During MySQL failover, MHA can automatically complete the failover operation within 0-30 seconds. ...
Posted by mattbrad on Thu, 24 Feb 2022 06:48:54 +0100
Ioc and annotation development
1. Spring configuration data source
1.1 function of data source (connection pool)
Data source (connection pool) is the key to improve program performanceInstantiate the data source in advance and initialize some connection resourcesGet from data source when using connection resourcesReturn the connected res ...
Posted by ITEagle03 on Wed, 23 Feb 2022 16:19:04 +0100
/******************* postgresql database test starts***********************/
--This test is based on pg database version 10.11
postgres=# select version();
PostgreSQL 10.11, compiled by Visual C++ build 1800, 64-bit
(1 Row record)
--Create a ...
Posted by engelsol on Wed, 23 Feb 2022 15:21:50 +0100