How to modify the initial password of a user in mysql5.7

When users install MySQL database for the first time, they always want to change the initial root password. I do the same and always search on Baidu. Here are some commonly used SQL for operating database and some basic concepts.

Modify the user's initial password:

SET PASSWORD = PASSWORD('your new password');
ALTER USER 'root'@'localhost' PASSWORD EXPIRE NEVER;
flush privileges;

Create a new user:

CREATE USER 'username'@'host' IDENTIFIED BY 'password';

Grant permissions to the user:

GRANT all privileges ON databasename.tablename TO 'username'@'host';
flush privileges;

To set and change your password:

SET PASSWORD FOR 'username'@'host' = PASSWORD('password');

Revoke permissions:

REVOKE privilege ON databasename.tablename FROM 'username'@'host';

To delete a user:

DROP USER 'username'@'host';

View the user's authorization:

SHOW grants for 'username'@'host';

The Innodb engine provides support for ACID transactions:

• A (Atomicity) means that a transaction is either fully executed or not executed;
• C (Consistency) means that the execution of a transaction does not change the consistency of the data in the database;
• I (Independence; Isolation) is also called isolation, which refers to the state in which two or more transactions are not executed alternately;
• D (Durability) means that after a transaction is successfully executed, the changes made will be persisted in the database and will not be rolled back for no reason;

MYSQL isolation level:

Dirty read: allows reading of uncommitted dirty data.

Non-repeatable read: Some records are read at point T1. When these records are read again at point T2, these records may have been changed or disappeared.
Phantom read: It solves the problem of non-repeatable reads and ensures that the query results in the same transaction are the same as when the transaction started.

MYSQL locking mechanism:

The locking mechanism is a rule set by the database to ensure the consistency of the database and make various shared resources orderly when being accessed concurrently.

• Row-level locking
• The granularity of the locked object is very small, which can easily cause deadlock, but the probability of locking resource contention is also minimal.
• Page-level locking
• Between row-level locking and table-level locking.
• Table-level locking

The most granular locking mechanism. Deadlock is not likely to occur, but the probability of resource competition is higher.

Table-level locking is mainly used in some non-transactional storage engines such as MyISAM, Memory, and CSV. Row-level locking is mainly used in Innodb and NDBCluster storage engines. Page-level locking is mainly used in BerkeleyDB.

The above is the method of changing the user's initial password in MySQL 5.7 that I introduced to you. I hope it will be helpful to you. If you have any questions, please leave me a message and I will reply to you in time. I would also like to thank everyone for their support of the 123WORDPRESS.COM website!