'commit' not having immediate effect

Table t1 (f1, f2). Primary key (f1, f2) Contents : ('1', 'one') and ('2' , 'two')
Table t2. Same as t1. Same key, same data.

I ran : select t1.f1 from t1 t1, t2 t2
  where exists (

     select 1 from dual where t1.f1 = t2.f1   )
I used 'dual' because 'null' did not work in its place; I was just trying out things.
This TOAD query/window hanged.

I opened another window, and ran :
update t1 set f1 = 'new' ;
commit ;
insert into t1 select * from t2 ;

I get the error : Primary Key Constraint Violation. I suspect that that hanged query has something to do with this problem.

Please advise. TIA. Received on Sat Apr 01 2006 - 08:33:40 CST