A system database
INFORMATION_SCHEMA: Virtual library, do not occupy disk space, storage is the database startup parameters, such as user table information, column information, permission information, character information, etc.
Performance_schema:mysql 5.5 started a new database: Mainly used to collect database server performance parameters, record the processing of query requests occurred in various events, locks and other phenomena
MySQL: Authorization library, access information for primary storage system users
Test:mysql Database System Auto-created test database
Two Create a database
1 syntax (help CREATE DATABASE)
CREATE database name CharSet UTF8;
2 Database naming rules:
can be by letter, number, underscore, @, #, $ case-sensitive uniqueness cannot use keywords such as create select cannot use the number maximum 128 bits alone
Three database related operations
1 View database show databases;show CREATE DATABASE Db1;select database (); 2 Select the database use database name 3 Delete the database the database name; 4 Modifying the database alter the DB1 charset UTF8;
Mysql (ii): library operations