Mysql5.7 how to change the user's initial password, mysql5.7 initial password

Mysql5.7 how to change the user's initial password, mysql5.7 initial password

When a user installs the MySQL database for the first time, he always wants to change the root initialization password. I am also trying to change the password every time. Below are some common SQL statements and some basic concepts for operating the database.

Modify the user's initialization 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 users:

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

Set and change the password:

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

Revoke permissions:

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

Delete A User:

DROP USER ‘username'@‘host';

View user authorization:

SHOW grants for ‘username'@‘host';

The Innodb Engine supports ACID transactions:

• A (Atomicity; Atomicity) indicates that A transaction is either fully executed or not executed;
• C (Consistency; Consistency) indicates that the transaction operation does not change the data Consistency 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 (persistence; Durability) means that changes made after a transaction is successfully executed will be permanently stored in the database and will not be rolled back for no reason;

MYSQL isolation level:

 

Dirty read: allows you to read uncommitted dirty data.

Repeatable reading: some records are read at T1. when you reread these records at T2. these records may have been changed or disappeared.
Phantom read: solves the problem of non-repeated read, and ensures that the query results in the same transaction are in the state at the beginning of the transaction.

MYSQL locking mechanism:

The locking mechanism is a rule set by the database to keep various shared resources in order to ensure Database Consistency.

• Row-Level Lock
• The granularity of the locked object is small, which may lead to deadlocks, but the probability of resource contention locking is also minimal.
• Page-Level Lock
• Between row-level locking and table-level locking.
• Table-Level Lock

Maximum granularity locking mechanism. It is not prone to deadlocks, but there is a high probability of resource competition.

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

The above section describes how to modify the initial password of a user using mysql5.7. I hope it will be helpful to you. If you have any questions, please leave a message and I will reply to you in a timely manner. Thank you very much for your support for the help House website!