error on rename of

[richard white]

Hi, i have a table that has a column referencing another table. it makes sense that if i try to delete the parent table then i am not allowed, but i am trying to drop the column that has the reference to the parent and it tells me error on rename of....

if i show create table i get the following result

qu_41_tb_24 | CREATE TABLE `qu_41_tb_24` (
`subjectID` bigint(20) NOT NULL,
`questionnaireID` bigint(20) NOT NULL,
`q_27` bigint(20) default NULL,
`q_29` date default NULL,
PRIMARY KEY (`subjectID`,`questionnaireID`),
KEY `q_27` (`q_27`),
CONSTRAINT `qu_41_tb_24_ibfk_1` FOREIGN KEY (`subjectID`, `questionnaireID`) R
EFERENCES `subjectquestionnaires` (`subjectID`, `questionnaireID`) ON DELETE CAS
CADE ON UPDATE CASCADE,
CONSTRAINT `qu_41_tb_24_ibfk_2` FOREIGN KEY (`q_27`) REFERENCES `lookup_qcompl
etor` (`lookupValue`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |

why cant i just delete the column q_27 without getting the error message:

mysql> alter table qu_41_tb_24 drop q_27;
ERROR 1025 (HY000): Error on rename of '.\portexunitich\#sql-17bc_a' to '.\portexunitich\qu_41_tb_24' (errno:150)

thanks very much for your help