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mysql

Inhaltsverzeichnis

MySQL ist eine Implementierung und Weiterentwicklung von SQL, einer Abfragesprache für die Kommunikation mit relationalen Datenbanken. Siehe auch MySQL (Powershell)

apt install mysql-server
mysql_secure_installation
mysql <database> -u <user> -p <password>

Examples

DESCRIBE mysql.user;
SELECT user,host FROM mysql.user;

CREATE USER 'user'@'%' IDENTIFIED BY 'password'; // statt '%' auch hostname oder ip;
ALTER USER 'user'@'%' IDENTIFIED BY 'newpassword';
DROP USER user;

CREATE DATABASE IF NOT EXISTS database;
DROP DATABASE database;

GRANT ALL PRIVILEGES ON database.* TO 'user'@'%';
GRANT SELECT,INSERT,UPDATE,DELETE ON database.* TO 'user'@'%';
FLUSH PRIVILEGES;
SHOW GRANTS FOR 'user'@'%';
REVOKE ALL ON database.* FROM 'user'@'%';
REVOKE ALL ON *.* FROM 'user'@'%';
REVOKE SELECT,INSERT,UPDATE,DELETE ON database.* FROM 'user'@'%';
DESCRIBE table;
CREATE TABLE IF NOT EXISTS 
user (
  id INT AUTO_INCREMENT PRIMARY KEY,
  email VARCHAR(255) NOT NULL,
  password VARCHAR(255) NOT NULL
) 
ENGINE = InnoDB;
DROP database `MyDatabase`;
TRUNCATE TABLE `MyTable`;
ALTER TABLE mytable MODIFY COLUMN mycolumn INT auto_increment PRIMARY KEY;
ALTER TABLE mytable MODIFY COLUMN mycolumn VARCHAR(10);
ALTER TABLE mytable ADD CONSTRAINT <fk_internalname> FOREIGN KEY (<fk_fieldname>) REFERENCES <foreign_table>(<foreign_table_field>) ON DELETE CASCADE;
// example 
// when a user gets deleted, delete all his posts
// ALTER TABLE posts ADD CONSTRAINT cascade_on_user_delete FOREIGN KEY (author) REFERENCES user(id) ON DELETE CASCADE
insert into users (name) values ("Test");
LOAD DATA INFILE 'C:/test.csv' 
INTO TABLE FileShare 
FIELDS TERMINATED BY ';'
OPTIONALLY ENCLOSED BY '"'
ESCAPED BY ''
LINES TERMINATED BY '\r\n'
IGNORE 1 ROWS
(TableA, TableB, TableC);

Joins

mysql.txt · Zuletzt geändert: 2024/10/16 14:00 von jango