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Information Schema INNODB_SYS_FOREIGN Table

The Information Schema INNODB_SYS_FOREIGN table contains information about InnoDB foreign keys.

The PROCESS privilege is required to view the table.

It has the following columns:

Column	Description
`ID`	Database name and foreign key name.
`FOR_NAME`	Database and table name of the foreign key child.
`REF_NAME`	Database and table name of the foreign key parent.
`N_COLS`	Number of foreign key index columns.
`TYPE`	Bit flag providing information about the foreign key.

The TYPE column provides a bit flag with information about the foreign key. This information is OR'ed together to read:

Bit Flag	Description
`1`	`ON DELETE CASCADE`
`2`	`ON UPDATE SET NULL`
`4`	`ON UPDATE CASCADE`
`8`	`ON UPDATE SET NULL`
`16`	`ON DELETE NO ACTION`
`32`	`ON UPDATE NO ACTION`

Example

SELECT * FROM INNODB_SYS_FOREIGN\G
*************************** 1. row ***************************
      ID: mysql/innodb_index_stats_ibfk_1
FOR_NAME: mysql/innodb_index_stats
REF_NAME: mysql/innodb_table_stats
  N_COLS: 2
    TYPE: 0
...

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https://mariadb.com/kb/en/information-schema-innodb_sys_foreign-table/