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catalogue I Log management of MySQL (1) Log classification of MySQL (2)MySQL log on (3) enter the database to check whether the corresponding log is enabled II MySQL full backup and recovery (1) Importance of data backup (2) Causes of data loss (3) Classification of database backup (4) Common backup methods ① Physical cold standby ② ...

1,pg_basebackup 1.1,pg_basebackup principle Official document: pg_basebackup (postgres.cn) 1) Create a checkpoint, open FPW (full page writes), and create a backup label (store checkpoint location, time and other information) 2) Establish a connection with the database through the stream replication protocol, and the WAL Sender process ...

Functions for MySQL Common Functions -- Mathematical operations SELECT ABS(-8) -- absolute value SELECT CEILING(9.4) -- ceil SELECT FLOOR(9.4) -- Rounding Down SELECT RAND() -- Return 0-1 random number SELECT SIGN(-10) -- Judging the sign 0 of a number-0 Negative Return-1 Positive number returns 1 -- String function SELECT CHAR_LENGTH( ...

Technical research background As the current R & D team is in the start-up stage of the company, there is no mature operation and maintenance system, and the ability to build and maintain the mature MQ commonly seen in the market is insufficient. However, we hope to have a lightweight message system for the members of the R & D team. T ...

Load MYSQL database driver The development tool used by the author is IntelliJ IDEA, and other integrated environments have similar principles. Download MYSQL database driver JDBC is java data base connectivity. In order to access the database on the MySQL database server, the application must ensure that the corresponding JDBC-MYSQL driver ...

PostgreSQL best practices for automatically creating partitionsintroductionPartition table is a feature of PostgreSQL in version 10. In actual use, users often need to create partitions in advance or create partitions in real time according to the written data. This paper discusses several common automatic partition creation schemes.sceneIn pra ...

Methods in the database: DDL: operation database and table 1. Operation database: CRUD 1. C(Create):establish * Create database: * create database Database name; * Create a database, judge that it does not exist, and then create: * create database if not exists Database name; * Create a database and specify a character set ...

Database design 1, Relationship between multiple tables 1. Classification: One to one (understanding): Such as: person and ID cardAnalysis: a person has only one ID card, and one ID card can only correspond to one person One to many (many to one): For example: departments and employeesAnalysis: a department has multiple employees, and ...

Introduction: This article summarizes mongodb 4 Some basic addition, deletion, modification and query operations of documents involved in X in mongo shell client, namely CRUD operation. For image download, domain name resolution and time synchronization, please click Alibaba open source mirror station 1, Create operations Create operation ...

Explain use and explanation Explain tool introduction Use the EXPLAIN keyword to simulate the database optimizer to execute SQL statements and analyze the performance bottlenecks of your query statements or structures Add the explain keyword before the select statement. MySQL will set a flag on the query. Executing the query will return the i ...