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/