hello, look at new patch from developer and found strange construction, here
I’ll try to reproduce what they want to do:
create table tt as select level id from dual connect by level <=100;
alter table tt add flag varchar2(50) default '' not null ;
Table altered.
select dump (flag,8 ) as dmp from tt ;
DMP
----------
NULL
NULL
…..
NULL
select count (*) from tt where flag is null;
COUNT(*)
----------
0
select count (*) from tt where flag is not null;
COUNT(*)
----------
100
How it is possible ? =)))
ps: if I add default null, then all goes well:
alter table tt add flag varchar2(50) default null not null ;
alter table tt add flag varchar2(50) default null not null
*
ERROR at line 1:
ORA-01758: table must be empty to add mandatory (NOT NULL) column
create table tt as select level id from dual connect by level <=100;
alter table tt add flag varchar2(50) default null not null ;
alter table tt add flag varchar2(50) default null not null
*
ERROR at line 1:
ORA-01758: table must be empty to add mandatory (NOT NULL) column
ps: sorry for my English
