Business Key Generation

[Tom Goring]

Hi,

I have a table that I need to migrate some data into:

CREATE TABLE `employee` (
  `employeeid` bigint(20) NOT NULL auto_increment,
..
  `reference` varchar(20) default NULL,
  `fkcompanyid` bigint(20) default NULL,
  PRIMARY KEY  (`employeeid`),
 KEY `FK4722E6AE82D7E095` (`fkcompanyid`),
CONSTRAINT `FK4722E6AE82D7E095` FOREIGN KEY (`fkcompanyid`) REFERENCES
`company` (`companyid`),
...
) ENGINE=InnoDB AUTO_INCREMENT=1000000000001585 DEFAULT CHARSET=latin1 |


My question is I want to generate a reference business key (a number) as the
migrated data is blank.

something like

update employee set reference = ROWNUM where fkcompanyid = X

I think in Oracle ROWNUM would help me do this.
I.e. generate a reference based on the position in the result set.

any Ideas ?

-- 
Tom Goring