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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