Let me see if I can re-phrase your comment – please verify that the following is what you are experiencing:

I have a view that accesses several tables, however I cannot issue UPDATE or DELETE statements against the view because I am receiving one of the following error messages:
* ORA-01752: cannot delete from view without exactly one key-preserved table (see page 276 of the “Beginning Oracle SQL” book)
* ORA-01779: cannot modify a column which maps to a non key-preserved table (see page 276 of the “Beginning Oracle SQL” book)

I have not yet tried using Instead-Of-Triggers (http://download.oracle.com/docs/cd/E14072_01/appdev.112/e10472/triggers.htm#i1006376 ). I have tried using the ROWID pseudo column from one of the tables to provide a unique column, but now the query returns no rows. Here is my view definition:

CREATE VIEW MY_VIEW AS
SELECT
  ROWID,
  T1.C1,
  T2.C2
FROM
  T1,
  T2
WHERE
  T1.C1=T2.C1;

Is the above a close representation of what you are trying to do? Please show the exact view definition and what you are trying to do with the view.