Programmer Help

1, The mysqldump command backs up data MySQL provides a convenient tool mysqldump for exporting database data and files from the command line. We can export database contents directly from the command line. #MySQL dump common mysqldump -u root -p --databases Database 1 database 2 > xxx.sql 2, mysqldump common operation examples 1. Back ...

Basic SELECT statement 1, SQL overview 1. SQL background In 1974, IBM researchers published a paper "sequence: a structured English query language", which unveiled database technology. Up to now, this structured query language has not changed much. Compared with other languages, the half-life of SQL can be said to be very long. S ...

preface Recently, when learning Lin Ziyu's big data, I found that installing Hive for Hadoop requires using MySQL database to save Hive metadata, rather than using Hive's own derby to store metadata. In order to fill the gap in the big data column, consult the materials to complete this blog. System version: Ubuntu 20.04 1, MySQL ins ...

Create a virtual environment under directory 123 c:/123 virtualenv 123 Installing flash 1.12 pip install flask==1.1.2 Install pymysql 1.0.2 pip install pymysql Install flash script pip install flask-script Install flash Sqlalchemy pip install flask-sqlalchemy When installing flash migrate, pay attention to ver ...

1, Introduction to master-slave replication 1.1 what is master-slave replication Copy the binlog log of the master server to the slave server for execution to achieve the consistent state of the master-slave data, which is called master-slave replication. In a word, what the master database does is what the slave database does. 1.2 why s ...

CentOS 7 Binary Installation MySQL 5.7 Environmental Science Host: CentOS Linux release 7.9.2009 (Core) Minimal Install Install using the Linux - Generic TAR package Mysql Compressed Pack Official Download Address: https://downloads.mysql.com/archives/community/ Select Version:5.7.31 Select Operating System:Linux - Generic Select OS Ve ...

Note: the following will use the emp table in the mysql database in the mysql database management system as an example This content continues from the previous study notes: DQL statement 2 in SQL (learning note 3) 1, Grouping function Grouping function is also called multi line processing function, and there are only 5 multi line proce ...

preface This is the self-study notes of crazy God's mysql, which is only for reference, learning and continuous updating The following is a video learning link: https://www.bilibili.com/video/BV1NJ411J79W 10. JDBC (key) 10.1. Database driver Driver: sound card, graphics card, database Our program will deal with the database throug ...

throw away a brick in order to get a gem When and when are we talking about the "pool"? I remember the last time it was an IO stream, I created a buffer pool to speed up the read / write speed (actually reducing the number of IO operations) So when will the connection pool be used??? Connection pooling is a technique for cre ...

mysql database notes DQL: query statement 1. Sort query 2. Aggregate function 3. Group query 4. Paging query constraint Relationship between multiple tables normal form Backup and restore of database DQL: query statement Sort query Syntax: order by clause order by sort field 1, sort by 1, sort field 2, sort by 2 Sort by: ...