Introduction to MySQL default database

Similar to large databases such as MS SQL Server, the MySQL database also provides built-in databases, which are:

• Information_schema

• Mysql

• Test

1.information_schema

The first database, INFORMATION_SCHEMA, provides a way to access database metadata. Metadata is data about the data, such as the database name or table name, the data type of the column, or access permissions. Some of the other terms used to express this information include the data dictionary and the system catalog.

INFORMATION_SCHEMA is an information database that holds information about all the other databases maintained by the MySQL server. In Information_schema, there are a few read-only tables. They are actually views, not basic tables, so you will not be able to see any files associated with them.

Each MySQL user has access to these tables, but only to specific rows in the table, where the user has the appropriate access rights to the object.

Now many people use phpMyAdmin to manage MySQL database, sometimes do not want to let ordinary users through phpMyAdmin see INFORMATION_SCHEMA database. We can set this up:

Set such a sentence in config.inc.php (some config.default.php)

$cfg [' Servers '] [$i] [' hide_db '] = ' information_schema ';

　　

2.mysql

Second database MySQL: This is the core database of MySQL, similar to the master table in SQL Server, which is responsible for the control and management information that MySQL needs to use, such as the user who stores the database, the permission settings, the keywords, and so on. Can not be deleted, if the MySQL is not very understanding, and do not easily modify the database inside the table information.

3.test

The third database is test: This is the installation time to create a testing database, and its name, is a complete empty database, no table, can be deleted.

This article is from the "Green Peak" blog, please make sure to keep this source http://zhuxianzhong.blog.51cto.com/157061/1829318

Introduction to MySQL default database