Mysql show create constraint?

Question

Hi,

Is there a easy way to query a table for its constraints(foreignkeys specificaly) like show create table, but for the constraints only?

thanks,

pvgoddijn

Answer 1

SHOW TABLE STATUS FROM db_name LIKE 'tbl_name';

The foreign key constraints are listed in the Comment column of the output.

Answer 2

MySQL 5.1 Manual

SHOW TABLE STATUS FROM db_name LIKE 'tbl_name';

Answer 3

select * from 
information_schema.KEY_COLUMN_USAGE 
where table_schema = <db_name> 
and table_name = <table_name>;

Answer 4

To show only the foreign key constraints you can check the constraint_type in information_schema.table_constraints and get the affected columns in information_schema.key_column_usage via a join

SELECT b.table_name, b.column_name, b.constraint_name,
       b.referenced_table_name, b.referenced_column_name
FROM information_schema.table_constraints a
JOIN information_schema.key_column_usage b
ON a.table_schema = b.table_schema AND a.constraint_name = b.constraint_name
WHERE a.table_schema=database() AND a.constraint_type='FOREIGN KEY'
ORDER BY b.table_name, b.constraint_name;