SequoiaDB Jushan database data field

Data Domain refers to a logical unit composed of several replication groups. Its main function is data isolation. A replication group can belong to multiple domains.The domain with 0 replication groups is called airspace. User cannot create assembly space in airspace.SYSDOMAIN is a predefined system domain. All replication groups belong to the ...

Posted by RoundPorch on Wed, 30 Mar 2022 01:19:19 +0300

Preliminary construction of TIDB-BINLOG

1, Introduction 1.TiDB Binlog is a commercial tool for collecting TiDB binlogs and providing quasi real-time backup and synchronization functions 1.1 application scenario Data synchronization: synchronize TiDB cluster data to other databases Real time backup and recovery: backup TiDB cluster data, and can be used for recovery in case of fai ...

Posted by mattwade on Tue, 29 Mar 2022 22:01:06 +0300

MySQL 8 builds MHA with one master and two slaves

1, Introduction MHA (Master High Availability) is a MySQL high availability solution. It is a management tool developed in perl language. It polls and detects the availability of MySQL master nodes, finds faults, automatically transfers faults, selects a slave node to be promoted to a new master node, replaces the old master node and continues ...

Posted by Soogn on Tue, 29 Mar 2022 18:19:02 +0300

day 05 DQL data query language --- connection query --- enter the room

Because sql statements are not case sensitive, all commands in this article use lowercase for convenience Previous contents day 01 first knowledge of Mysql and DDL data definition languageday 02 DML data operation languageday 03 DQL data query language -- a first glimpseday 04 DQL data query language - single table query - a slight succ ...

Posted by kampbell411 on Tue, 29 Mar 2022 07:33:25 +0300

java training on how to use reflection as a simple Spring IOC container

preface After learning Spring, I have a strong interest in its working principle. In recent days, I have seen the video to understand the working principle of some SpringIOC containers, and made a very simple SpringIOC container while playing and grinding, realizing its functions of XML file assembly, java code assembly and automatic assembly. ...

Posted by lostprophetpunk on Sun, 27 Mar 2022 11:36:28 +0300

Redis basic data types

Introduction to Redis Redis is a database based on memory storage, which can be persistent (RDB, AOF);Based on key value storage, value supports multiple data types,Support cluster and transaction;Redis has 16 databases by default, which can be set in the configuration file (databases 16);Redis is single thread + IO multiplexingThe operation o ...

Posted by nfr on Sun, 27 Mar 2022 10:45:39 +0300

oracle quick start Chapter 6 triggers & built-in packages

1: Trigger 1. Key words of trigger: trigger 2. Overview: it is a special stored procedure, and the stored procedure is a special function When the DML (data manipulation language) statement is executed, the trigger will be triggered and executed automatically, rather than requiring manual call like a function. 3. Syntax of trigger: create ...

Posted by headmine on Sun, 27 Mar 2022 09:15:10 +0300

Creation and management practice of SQL basic data table

Experimental reportexperimentRead data table 1-table 4 and consider whether it is reasonable to add constraints to each fieldWrite T-SQL statements, create tables and constraintsView information about creating tablesVerify data integrity by inserting data into the table and answer the appropriate questionsExperimental task 1Using T-SQL to compl ...

Posted by Exemption on Sat, 26 Mar 2022 22:05:12 +0300

On the perfect scheme of Redission to realize distributed lock and Lua script

On the perfect scheme of Redission to realize distributed lock and Lua script preface In the previous article, I mentioned the redis distributed lock implementation and lua script related knowledge In some scenarios, multiple processes must monopolize and share resources in a mutually exclusive manner. At this time, distributed lockin ...

Posted by andreas on Sat, 26 Mar 2022 17:19:12 +0300

Detailed and complete knowledge of sql statements

Modify database table Modify table name: alter table Old table name rename as New table name Add table fields alter table Table name add Field column properties For example: alter table student age int(11) Modify the fields of the table Modify constraints alter table Table name modify Field column properties[]; For example: ...

Posted by jyushinx on Sat, 26 Mar 2022 12:26:12 +0300