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sql and functions commonly used in oracle TO_DATE, EXISTS, CASE... WHEN functionLISTAGG function and OVER PARTITION BY functionFind out whether a value exists in the whole database in Oracle databaseoracle sql statement specification, creating columns, adding columns, deleting columns, functions, etcFunction that returns the time difference b ...

Pull mysql image docker pull mysql:5.7.36 Create container Create the following folders master slave1 slave2 Create master database docker run \ --name mysql-master \ -p 3307:3306 \ -v /usr/local/docker/mysql/data/master:/var/lib/mysql \ -e MYSQL_ROOT_PASSWORD=root \ -d mysql:5.7.36 Create slave database 1 docker run \ --name m ...

1, Basic knowledge 1. Role of backup and restore: Backup mainly plays the role of data disaster recovery. It is an effective means to ensure data security in case of database failure; By restoring the backup set data, the data can be restored to the state before the database failure. 2. Basic principles of backup, restore and recovery: In D ...

1. History of database operation framework 1,JDBC JDBC (Java database connection) is a Java API used to execute database SQL statements. It can provide unified access to a variety of relational databases. It is composed of a group of classes and interfaces written in Java language. JDBC provides a benchmark, which can build more advanc ...

MySQL database Database overview Database related concepts DB Database: it is "a warehouse that organizes, stores and manages data according to data structure". Is a long-term storage in the computer, organized, shareable, unified management of a large number of data collection. It is essentially a file system, which exists on ...

2, MySQL introduction and installation 1 Introduction Mysql database is subordinate to MySQL AB company, headquartered in Sweden and later acquired by Oracle. Official website: https://www.mysql.com/ 2 advantages Low cost: open source, generally free to use. High performance: fast execution. Simple: easy to install and use. 3. MySQL ver ...

-DQL operation table record - query [ key ] 7.1 basic query syntax select Field name to query from Table name [where condition] 7.2 simple query 7.2.1 query records of all rows and columns grammar select * form surface Query all the columns in the commodity table select * from product; 7.2.2 query records of specific columns in a t ...

I am participating in the CSDN "new programmer" award-winning essay solicitation There are thousands of people in the vast sea. Thank you for seeing here this second. I hope my article will help you! May you keep your love and go to the mountains and seas in the future! 1. Basic knowledge of database 1.1 why learn database ...

1. Description of index caliber Retained on the next day: the number of users who use the product on the first day and still use it on the second day Multi day retention: the number of users who use the product on the first day and still use it after many days Number of people continuously active: how many people continuously use products 2 ...

view Views are other objects in the database 1. What is a view You can create a view of a table to represent a logical subset of data or a combination of data. A view is a logical table based on a table or another view. A view does not contain its own data. It is like a window through which you can view or change the data in the table. T ...