In addition to Weibo, there is also WeChat
Please pay attention
WeChat public account
Shulou
2025-04-01 Update From: SLTechnology News&Howtos shulou NAV: SLTechnology News&Howtos > Development >
Share
Shulou(Shulou.com)06/03 Report--
This article mainly introduces what information_schema is in MySQL, which has certain reference value. Interested friends can refer to it. I hope you will gain a lot after reading this article. Let Xiaobian take you to understand it together.
In MySQL, the information_schema is thought of as a database, specifically an information database. It holds information about all other databases maintained by MySQL Server. Such as database name, database table, table column data type and access rights, etc.
information_schema Introduction
In INFORMATION_SCHEMA, there are several read-only tables. They are actually views, not base tables, so you won't be able to see any files associated with them.
information_schema Database table description:
SCHEMATA table: Provides information about all databases in the current instance of mysql. The results of showdatabases are taken from this table.
TABLES tables: Provides information about tables in the database, including views. Details which schema a table belongs to, table type, table engine, creation time and other information. The results of showtables from schema are taken from this table.
COLUMNS Table: Provides column information in the table. Details all columns of a table and information about each column. The results of showcolumnsfromschemaname.tablename are taken from this table.
STATISTICS Table: Provides information about the table index. Results for showindexfromschemaname.tablename are taken from this table.
USER_PRIVILEGES table: Gives information about global permissions. This information is derived from the mysql.user authorization table. Non-standard table.
SCHEMA_PRIVILEGES table: Gives information about schema (database) permissions. This information comes from the mysql.db authorization table. Non-standard table.
TABLE_PRIVILEGES table: Gives information about table permissions. This information is derived from the mysql.tables_priv authorization table. Non-standard table.
COLUMN_PRIVILEGES table: Gives information about column permissions. This information is derived from the mysql.columns_priv authorization table. Non-standard table.
CHARACTER_SETS table: Provides information about the character sets available for mysql instances. Yes SHOWCHARACTERSET result set taken from this table.
COLLATIONS table: Provides information about the collation of character sets.
COLLATION_CHARACTER_SET_APPLICATION table: Indicates the character set available for collation. These columns are equivalent to the first two display fields of SHOWCOLLATION.
TABLE_CONSTRAINTS table: Describes the table where constraints exist. And the constraint type of the table.
KEY_COLUMN_USAGE table: Describes key columns with constraints.
ROUTINES table: Provides information about stored subroutines (stored procedures and functions). At this point, the ROUTINES table does not contain custom functions (UDFs). A column named "mysql.procname" indicates the mysql.proc table column corresponding to the INFORMATION_SCHEMA.ROUTINES table.
VIEWS table: Gives information about views in the database. View information cannot be viewed unless you have showviews permission.
TRIGGERS table: provides information about triggers. You must have super permission to view this table
Thank you for reading this article carefully. I hope that the article "What is information_schema in MySQL" shared by Xiaobian will be helpful to everyone. At the same time, I hope that everyone will support you a lot and pay attention to the industry information channel. More relevant knowledge is waiting for you to learn!
Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.
Views: 0
*The comments in the above article only represent the author's personal views and do not represent the views and positions of this website. If you have more insights, please feel free to contribute and share.
Continue with the installation of the previous hadoop.First, install zookooper1. Decompress zookoope
"Every 5-10 years, there's a rare product, a really special, very unusual product that's the most un
© 2024 shulou.com SLNews company. All rights reserved.