MySQL外键级联删除不起作用，完全陷入困境

Question

I have read a bunch of other threads on this but I am still stumped. I have created a two very simple tables as a sanity check and unable to get them to preform a cascade delete so need some help at this point.

CREATE TABLE `test1` (
  `test1_ID` int(11) NOT NULL AUTO_INCREMENT,
  `test1_name` char(15) DEFAULT NULL,
  PRIMARY KEY (`test1_ID`),
  UNIQUE KEY `test1_ID_UNIQUE` (`test1_ID`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

CREATE TABLE `test2` (
  `test2_ID` int(11) NOT NULL AUTO_INCREMENT,
  `test2_FK_test1` int(11) NOT NULL,
  `test2_name` char(15) DEFAULT NULL,
  PRIMARY KEY (`test2_ID`),
  UNIQUE KEY `test2_ID_UNIQUE` (`test2_ID`),
  KEY `IDX_test2_FK_test1` (`test2_FK_test1`),
  CONSTRAINT `FK_test2__test1` FOREIGN KEY (`test2_FK_test1`) REFERENCES `test1` (`test1_ID`) ON DELETE CASCADE ON UPDATE NO ACTION
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

Table data used for testing

Test 1 Table Data:
+----------+------------+
| test1_ID | test1_name |
+----------+------------+
|        1 | test1 r1   |
|        2 | test1 r2   |
+----------+------------+

Test 2 Table Data:
+----------+----------------+----------------+
| test2_ID | test2_FK_test1 | test2_name     |
+----------+----------------+----------------+
|        1 |              1 | Test2 R1 - FK1 |
|        2 |              1 | Test2 R2 - FK1 |
|        3 |              1 | Test2 R3 - FK1 |
+----------+----------------+----------------+

Insert statements:
INSERT INTO `test1` VALUES (1,'test1 r2'),(2,'test1 r2');
INSERT INTO `test2` VALUES (1,1,'Test2 R1 - FK1'),(2,1,'Test2 R2 - FK1'),(3,1,'Test2 R3 - FK1');

If I delete the first row from the test1 table nothing happens to the test2 table data

DELETE FROM test1 WHERE test1_ID = 1;

Answer 1

It turned out to be a bug in the version of MySQL I was using, 5.5.28. I just upgraded to 5.6.13 and everything works now. Thanks for the help.

Answer 2

Make sure mysql "foreign key checks" is enabled:

select @@FOREIGN_KEY_CHECKS;

set FOREIGN_KEY_CHECKS=1;

Answer 3

I've found that calling PDO::exec('SET FOREIGN_KEY_CHECKS=1') is necessary for PDO to respect ON DELETE and ON UPDATE actions. For some reason, foreign key constraints are disabled by default on my system.