5. MySQL 8.0 reference manual 3.3.4.2 select specific lines

3.3.4.2 select a specific line As shown in the previous section, it is easy to retrieve the entire table. As long as the WHERE clause in the statement is omitted SELECT . But usually you don't want to see the whole table, especially when it gets bigger. Instead, you are usually more interested in answering specific qu ...

Posted by pranav_kavi on Tue, 31 Mar 2020 04:06:42 -0700

Installing mysql environment under linux

1. When installing apache, it has been checked that there is no mysql native to centos installed locally. If there is any, it must be uninstalled, or the port may be occupied 2. Prepare mysql installation package (note that when compiling, the compilation of mysql 5.5 and above is different from that of mysql 5.5 and below. 5.5 needs to be comp ...

Posted by Honor on Mon, 30 Mar 2020 11:37:11 -0700

mysql primary and primary data synchronization, hot standby

The principle of MySQL master master synchronization and master-slave synchronization is the same, except that both sides are master-slave roles. Environmental Science Operating system version: CentOS7 64 bitMySQL version: mysql5.6.33Node 1IP: 192.168.1.205 host name: edu-mysql-01Node 2IP: 192.168.1.206 host name: edu-mysql-0 ...

Posted by swampone on Mon, 30 Mar 2020 11:30:37 -0700

java inserts time into mysql and formats time and date

Several ways of Java inserting current time into MySQL and several ways of java time date format: (refer to network resources for information) Several ways of java inserting current time into MySQL The first is to convert the time of type java.util.Date to the time of type java.sql.Date recognized by mysql database Note: ja ...

Posted by ghostdog74 on Mon, 30 Mar 2020 10:21:31 -0700

MySQL Pt online tool installation and use

In the production environment, the ddl execution of mysql does not affect the normal use of online, and the tool Pt online is often used Install Pt Online Install DBI wget http://www.cpan.org/modules/by-module/DBD/DBI-1.634.tar.gztar -xf DBI-1.634.tar.gzcd DBI-1.634/ perl Makefile.PLmake && sudo make install Install ...

Posted by sheac on Sun, 29 Mar 2020 11:44:11 -0700

Java database development (1): JDBC connection database

1, MySQL database 1. Create database CREATE DATABASE jdbc CHARACTER SET 'utf8'; 2. build tables CREATE TABLE user ( id int(10) NOT NULL AUTO_INCREMENT, userName varchar(20) NOT NULL, PRIMARY KEY (id) ); 3. Add data 2, Connect MySQL database through JDBC 1.JDBC URL 2.Statement boolean execute(String SQL): if the ResultSet object can be ...

Posted by katlis on Sun, 29 Mar 2020 11:35:55 -0700

redis master-slave configuration (one master-many slave)

Introduction of Master and Subordinate redis installation 1. Master-Subordinate-Usage Like MySQL, redis support master-slave synchronization, as well as a master-slave and multilevel slave structure. The primary-slave architecture is designed for purely redundant backups, and for improved read perf ...

Posted by SpaceLincoln on Sat, 28 Mar 2020 10:36:48 -0700

The use of BeanListHandler interface in DBUtils

Original link: http://www.yiidian.com/dbutils/dbutils-beanlisthandler.html org.apache.commons.dbutils.BeanListHandler is the implementation of the ResultSetHandler interface, and is responsible for converting all records at the ResultSet result level to the List collection of JavaBean s. This class is thread safe. 1 syntax for beanlisthandler L ...

Posted by codygoodman on Sat, 28 Mar 2020 07:55:12 -0700

hive-1.2.1 Installation and Simple Use

Hive can only be installed on one node 1. Upload tar package 2. Decompression tar -zxvf hive-1.2.1.tar.gz -C /apps/ 3. Install mysql database (switch to root user) (there are no limitations on where to install, only nodes that can connect to the hadoop cluster) 4. Configure hive (a) Configure the HIVE_HOME environment variable vi conf/hive-e ...

Posted by gyash on Thu, 26 Mar 2020 21:12:15 -0700

2020Python job 15 -- decorator 2 + iterator

@2020.3.24 (Q1) Homework:1. Compile the parametric decorator explained in class def auth(db_type = 'file'): def inner(func): def wrapper(*args, **kwargs): inp_name = input("your name:").strip() inp_pwd = input("your password:").strip() if db_type == 'file': with open(r'd ...

Posted by JayNak on Wed, 25 Mar 2020 07:33:21 -0700