I have this trigger:

CREATE OR REPLACE TRIGGER TBLWCONT_AI_ROW AFTER
INSERT OR
UPDATE OF CONTENT, IDDOCUMENT,IDUSERWHOCREATE,
IDWORKINGCONTENT
ON TBLWORKINGCONTENT
FOR EACH ROW begin
if inserting then
INSERT INTO tblworkingcontentversion (idworkingcontentversion,content,IdWorkingContent,IdUser,MinorVersion, idDocument) values
(sq_tblwcontvers.nextval,:new.content,:new.idworkingcontent,:new.iduserwhocreate,1,:new.iddocument);
end if;
if UPDATING then
INSERT INTO tblworkingcontentversion (idworkingcontentversion,Content,IdWorkingContent,IdUser, idDocument) values
(sq_tblwcontvers.nextval,:new.content,:new.idworkingcontent,:new.iduserwhocreate,:new.iddocument);
end if;
end;



content is a clob type.

And I had the following error:

ORA-25006: cannot specify this column in UPDATE OF clause
Cause: Attempt to create a trigger on update of a column whose datatype is disallowed in the clause, such as LOB and nested table.

I don't know how to do this because that's just what I want to do.
A trigger that trggers on the update of the clob datattype.

Please help

Edli