Klucz obcy na kilku polach Opcje

[Indeo]

Czy da się w mysql zbudować klucz obcy będący kombinacją kilku pól?
Są dwie tabele
Nadrzędna A:

Kod

col1,col2,col3
   1|   1| Ala
   1|   2| Kasia
   2|   1| Basia
   2|   2| Zosia
PRIMARY KEY on (col1,col2)

Podrzędna B:

Kod

col1,col2,col4
   1|  1| 34
   1|  1| 12
   1|  2| 67
   2|  1| 98
PRIMARY KEY on (col1,col2,col4)

i chcę teraz żeby usuwając rekord z tabeli A o danej wartości klucza (col1,col2)
osunięte zostały z tabeli B wszystkie rekordy dla których B(col1,col2)=A(col1,col2)
Jak to zapisać?

[nospor]

a czy zajrzenie do manuala:
http://dev.mysql.com/doc/refman/5.1/en/inn...onstraints.html
i wyczytanie czy jest to możliwe czy nie to tak cięzko?

[Indeo]

Mam taki kod sql tworzący dwie tabele i na końcu foreign key:

[SQL] pobierz, plaintext 
 CREATE TABLE IF NOT EXISTS `app_forms` (
  `window_id` varchar(255) COLLATE utf8_polish_ci NOT NULL,
  `form_id` varchar(255) COLLATE utf8_polish_ci NOT NULL,
  `form_title` varchar(255) COLLATE utf8_polish_ci NOT NULL,
  `form_width` int(4) NOT NULL DEFAULT '300',
  `action` varchar(255) COLLATE utf8_polish_ci NOT NULL DEFAULT 'index.php',
  `method` enum('GET','POST') COLLATE utf8_polish_ci NOT NULL DEFAULT 'GET',
  PRIMARY KEY (`window_id`(64),`form_id`(64)),
  KEY `window_id` (`window_id`),
  KEY `form_id` (`form_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_polish_ci;
 
 CREATE TABLE IF NOT EXISTS `app_datasets` (
  `window_id` varchar(255) COLLATE utf8_polish_ci NOT NULL,
  `form_id` varchar(255) COLLATE utf8_polish_ci NOT NULL,
  `data_id` varchar(255) COLLATE utf8_polish_ci NOT NULL,
  `query` text COLLATE utf8_polish_ci NOT NULL,
  `klucz` varchar(255) COLLATE utf8_polish_ci DEFAULT NULL,
  `outer_klucz` varchar(255) COLLATE utf8_polish_ci NOT NULL,
  `readonly` enum('yes','no') COLLATE utf8_polish_ci NOT NULL DEFAULT 'no',
  PRIMARY KEY (`window_id`(64),`form_id`(64),`data_id`(64)),
  KEY `window_id` (`window_id`),
  KEY `form_id` (`form_id`),
  KEY `data_id` (`data_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_polish_ci;
 
 ALTER TABLE `app_datasets` ADD 
CONSTRAINT `app_datasets_window_id_form_id_fk` 
 FOREIGN KEY (`window_id`,`form_id`)
 REFERENCES 
 `app_forms` (`window_id`,`form_id`) 
 ON DELETE CASCADE;
[SQL] pobierz, plaintext 

i dostaje error:

Kod

#1005 - Can't create table 'test.#sql-848_1cb' (errno: 150)

i wielki płacz
Co robię nie tak?

[nospor]

NIe zebym sie czepial, ale na stronie do ktorej dalem ci linka masz ten problem opisany...

Also, it is interesting to note that while this query works (Note the PRIMARY KEY line):

CREATE TABLE `ffxi_characterJob` (
`serverID` int(11) NOT NULL,
`userid` int(10)unsigned NOT NULL,
`characterName` varchar(255) NOT NULL,
`jobAbbr` char(4) NOT NULL,
`jobLevel` int(11) default '0',
PRIMARY KEY (`serverID`,`userid`,`characterName`,`jobAbbr`),
INDEX (`jobAbbr`),
CONSTRAINT FOREIGN KEY (`serverID`,`userid`,`characterName`) REFERENCES `ffxi_characters` (`serverID`,`userid`,`characterName`) ON DELETE CASCADE ON UPDATE CASCADE,
CONSTRAINT FOREIGN KEY (`jobAbbr`) REFERENCES `ffxi_jobType` (`jobAbbr`) ON DELETE CASCADE ON UPDATE CASCADE
) TYPE=InnoDB;

This query will give you an error 1005 and errno 150:

CREATE TABLE `ffxi_characterJob` (
`serverID` int(11) NOT NULL,
`userid` int(10)unsigned NOT NULL,
`characterName` varchar(255) NOT NULL,
`jobAbbr` char(4) NOT NULL,
`jobLevel` int(11) default '0',
PRIMARY KEY (`jobAbbr`,`serverID`,`userid`,`characterName`),
INDEX (`jobAbbr`),
CONSTRAINT FOREIGN KEY (`serverID`,`userid`,`characterName`) REFERENCES `ffxi_characters` (`serverID`,`userid`,`characterName`) ON DELETE CASCADE ON UPDATE CASCADE,
CONSTRAINT FOREIGN KEY (`jobAbbr`) REFERENCES `ffxi_jobType` (`jobAbbr`) ON DELETE CASCADE ON UPDATE CASCADE
) TYPE=InnoDB;

In order to make the second one work, you have to add:
INDEX (`serverID`,`userid`,`characterName`)
before the the foreign key is made.

Jakby co to podane tu rozwiązanie działa.