% mysql test
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Your MySQL connection id is 183
Server version: 5.1.41-3ubuntu12.6 (Ubuntu)
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> \W
Show warnings enabled.
mysql> create table foo(foo_id int primary key) engine=InnoDB;
Query OK, 0 rows affected (0.00 sec)
mysql> create table bar(
-> foo_id int references foo (foo_id)
-> ) engine=InnoDB;
Query OK, 0 rows affected (0.01 sec)
mysql> show create table bar\G
*************************** 1. row ***************************
Table: bar
Create Table: CREATE TABLE `bar` (
`foo_id` int(11) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1
1 row in set (0.00 sec)
/* ^ Notice the glaring lack of foreign key constraint?!?
* No errors, no warnings, no constraint.
*
* http://dev.mysql.com/doc/refman/5.1/en/innodb-foreign-key-constraints.html
*
* "Furthermore, InnoDB does not recognize or support “inline REFERENCES
* specifications” (as defined in the SQL standard) where the references are defined
* as part of the column specification. InnoDB accepts REFERENCES clauses only when
* specified as part of a separate FOREIGN KEY specification."
*/