Programmer Group

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 ...

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 ...

Write before: Recently, the old project has added the need of daily report optimization. Li Jie asked me to use triggers to update the daily report data when inserting or updating data. Mm-hmm-hmm. when I was learning database, I met triggers, but they all jumped by, and I didn't really practice them. This time, I have the right to learn again~ ...

Basic introduction Bridge mode is a structural design mode. Put the implementation and abstraction in two different class levels, so that the two levels can be changed independently. Based on the minimum design principle of class, different classes are given different responsibilities through encapsulation, aggregation, inheritance and other b ...

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 ...

Parameterless stored procedure: create or replace procedure sayhello as --Explanation part begin dbms_output.put_line('hello world'); end; 1 2 3 4 5 6 Two call methods of command window 1. SQL> set serveroutput on; --The first time I have to drive SQL> exec sayhello hello world PL/SQL procedure successfully comple ...

1. PlSql programming procedure language In the sql statement of database, the common definition of variable condition judgment cycle structure is added to the statement of process 1) . basic grammatical structure declare – declaration part – similar to defining variables begin &nda ...

The requirements are as follows. There are already generated good spatial data, including date, hour, longitude, latitude, number of people. Use GeoServer to generate heat map. This article uses the PostgreSQL10 database and has added PostGIS support. Create table create table table_test( day varchar(8), hour int, lon nu ...

It has been updated to some simple basic types until one day an update operation covering a certain field (this field is an array) was written. There is a problem. There is a problem in the database A little confused. Of course, if we set the type when updating, this problem will not occur. One of the preconditions for this problem is that we a ...

Thank you for your reference- http://bjbsair.com/2020-03-27/tech-info/7042/ Summary It is well known that the machine name of the client is recorded in the v$session, but there is no IP. How to record the clinet ip?  select username,machine,terminal,program,client_info,logon_time from v$session; It can be seen that there is no IP record.. 1 ...