Nsert/Update and Add Column at the same Table and at the "same" Time

Question

Hello,
I want Insert/Update and Add Column at the same Table and at the "same" Time but in different sessions.
Example:
At first the "insert/update" statement:
Insert into TestTable (Testid,Value) values (1,5105);
After that the "add" statement:
Alter table TestTable add TestColumn number;
- sadly now I get the message: ORA-00054: resource busy and acquire with NOWAIT specified
"insert/update" statement:
Insert into TestTable (Testid,Value) values (2,1135);
After that the execute commit.
I don't know when the first session set the commit statement so I want that the DB the "Alter Table..." statement execute if it's possible.
If it's possible I want to save a repeat loop with the "Alter Table..." statemtent.
Thanks for ideas

Answer 1

Well I want to walk in the rain without and umbrella and still stay dry, but it ain't gonna happen.
You can't run a DDL statement against a table with transactions pending. Session 2 has to wait until session commits or rollbacks (or until the session is killed). That's just the way it is.
This makes sense if you think about it. The data dictionary has to be consistent across all sessions. If session 2 was allowed to change the table structure whilst session 1 has a pending transaction then the database is in an inconsistent state. This is easier to see if you consider the reverse situation - the ALTER TABLE statement run by session 2 does a DROP COLUMN TESTID rather than adding a column: now what should happen to session 1's INSERT statement? You have retrospectively invalidated a statement that was perfectly legal when it was executed.
If it's possible I want to save a repeat loop with the "Alter Table..." statemtent.Fnord.
Cheers, APC