Can't write Null into nullable field?

Hello everyone. Using SQL Worksheet, I typed the following :

SQLWKS> describe content

Column Name                    Null?    Type

......blah blah foo biz baz

PREV_CONTENT_ID                         NUMBER(9)
NEXT_CONTENT_ID                         NUMBER(9)

Fine. I then attempt the following :

update content set prev_content_id = 'Null' where content_id = 3070

...and get the following error message : ORA-01722: invalid number

From the looks of the description of this table, prev_content_id is nullable, yet I get an error trying to save Null into this field. Could someone please shed some light on this one?

Thanks very much in advance,

Rich Received on Thu Jan 06 2000 - 14:06:09 CST