Column Value Corrupted After DDL Operations (Doc ID 1924931.1)

Last updated on FEBRUARY 25, 2019

Applies to:

Symptoms

Adding new column after dropping column with default value leads to values corruption.

Steps to reproduce:

SQL> drop table xx;
create table xx (x number);
insert into xx (x) values (1);
commit;

alter table xx add (
  c varchar2 (100),
  cx varchar2 (100),
  f char (1) default 'n' not null,
  fx char (1) default 'n' not null);

alter table xx drop (
  cx,
  fx);

alter table xx add (
  na number (10),
  nb number (4));

select nb from xx;
select dump (nb) from xx;

Table dropped.

SQL>
Table created.

SQL>
1 row created.

SQL>
Commit complete.

SQL> SQL> 2 3 4 5
Table altered.

SQL> SQL> 2 3
Table altered.

SQL> SQL> 2 3
Table altered.

SQL> SQL>
  NB
----------


SQL>
DUMP(NB)
----------------------------------------
Typ=2 Len=1: 110

SQL>

Now "na" and "nb" are expected to be null, but they have the values from removed columns, filled previously by default values.

Changes

Cause

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