MySQL implements grouping and sorting
We want to extract the second order information of all users in descending order according to the user group and the order time of the user.
This belongs to group sorting. There are built-in functions in Oracle that can be implemented, but in mysql, it's a bit troublesome:
CREATE TABLE user_orders (orders_id INT UNSIGNED NOT NUL ...
Posted by Iron Bridge on Mon, 16 Dec 2019 15:39:05 +0100
MMM high availability cluster of MySQL database
MMM Cluster Architecture Overview
Mmm (Master Master replication manager Mysql) is a set of flexible script program based on perl, which is used to monitor and migrate mysql replication, and manage the configuration of Mysql master replication (only one node is writable at the same time).
MMM high availability architecture description
Mmm M ...
Posted by synergypoint on Fri, 13 Dec 2019 17:12:51 +0100
Scratch: Top 250 crawling
Content of this article
Climb to the top 250 page of Douban movie. The fields include:Ranking, title, director, one sentence Description: some are blank, rating, number of evaluation, release time, release country, category
Grab data storage
scrapy introduction
Scrapy crawler framework tutorial (1) -- getting started with scrapy
Create projec ...
Posted by JCBarry on Thu, 12 Dec 2019 20:53:55 +0100
Summary of mysql8.x single machine installation
1. Download the mysql installation package, extract the installation file, and change the name to mysql
wget https://cdn.mysql.com//Downloads/MySQL-8.0/mysql-8.0.13-linux-glibc2.12-x86_64.tar.xz
2. Create data directory in mysql folder
mkdir data
3. Create mysql user group and mysql user
groupadd mysql
useradd -g mysql mysql
4. Change ...
Posted by shellyrobson on Thu, 12 Dec 2019 15:22:48 +0100
How to write results to MySQL in Spark
The Spark mentioned here includes SparkCore/SparkSQL/SparkStreaming. In fact, all operations are the same. The following shows the code in the actual project.
Method 1: write the entire DataFrame to MySQL at one time (the Schema of DataFrame should be consistent with the domain name defined in the MySQL table)
Dat ...
Posted by blacksheepradio on Wed, 11 Dec 2019 06:08:20 +0100
Basic use of Express
Preface
List project Express is a brief and flexible node.js Web application framework, which provides a series of powerful features to help you create various Web applications and rich HTTP tools.
text
A simple example of express framework
// Download express
cnpm install express --save
// Quote
import expre ...
Posted by I Am Chris on Wed, 11 Dec 2019 01:35:07 +0100
Spring cloud Alibaba microservice Practice II - service registration
Introduction: in the previous article, we have prepared the basic components based on spring cloud Alibaba. The main content of this issue is to register all services into Nacos, and enable account service and product service to provide basic addition, deletion, modification and query capabilities.
Basic framework construction
Create a multi m ...
Posted by kamasheto on Tue, 10 Dec 2019 22:52:57 +0100
Integer tinyint of [numeric type] of data type
1.1 tinyint description
id tinyint(M) [UNSIGNED] [ZEROFILL]
Field name field type (length) [unsigned] [leading fill]
unsigned:
01: tinyint(M) followed by the unsigned parameter is unsigned (tinyint range is 0 ~ 255)
02: tinyint(M) without unsigned parameter and zerofill parameter is signed (tinyint range is - 128 ~ 127)
zero ...
Posted by wscreate on Tue, 10 Dec 2019 04:48:51 +0100
xtrabackup of mysql data backup
Last article This article briefly introduces mysqldump's backup and recovery of database. This article introduces another backup tool xtrabackup. In the era of InnoDB transaction engine flooding, xtrabackup can well support hot backup of database, which is very gratifying,
Xtrabackup is available in the epel source, so you can install it dir ...
Posted by dmort on Tue, 10 Dec 2019 03:14:13 +0100
Implementation of spring cloud Alibaba rocketmq asynchronous communication
This article discusses how to use RocketMQ Binder to subscribe and publish Spring Cloud application messages.
introduce
RocketMQ It is an open source distributed message system. Based on the highly available distributed cluster technology, it provides low latency and highly reliable message publishing and subscription services, which are widely ...
Posted by Cleibe on Mon, 09 Dec 2019 05:36:31 +0100