changing columns to not null one or many at a time

Oracle v7.3.2.1
I tested with a large table on AIX with no user access and it appears that

alter table LARGE_TABLE modify
(COLUMN1 not null,COLUMN2 not null,COLUMN3 not null, COLUMN4 not null)
/

completes at the SAME speed as:

alter table LARGE_TABLE modify (COLUMN1 not null)
/

alter table LARGE_TABLE modify (COLUMN2 not null)
/

alter table LARGE_TABLE modify (COLUMN3 not null)
/

alter table LARGE_TABLE modify (COLUMN4 not null)
/

Is this due to the former statement actually fixing one column at a time OR that the tables blocks are in memory for consequent alters on the same table.

thanks

Greg Received on Mon Dec 17 2001 - 19:31:21 CET