RE: default constraint updating existing rows

Thanks a lot, If I specify not null then I can understand Oracle need to update existing rows but not sure why they are trying to update existing rows for null column. I tried on other RDBMS and they only update rows if not null is specified otherwise leave the existing rows null.

-----Original Message-----

From: Hostetter, Jay M [mailto:JHostetter_at_decommunications.com] Sent: Tuesday, December 16, 2008 1:44 PM To: Harvinder Singh; oracle-l_at_freelists.org Subject: RE: default constraint updating existing rows

Try splitting the "alter table" into two different statements.

Alter table test add (b int);

Alter table test modify (b int default 3);

Jay

-----Original Message-----

From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Harvinder Singh Sent: Tuesday, December 16, 2008 1:22 PM To: oracle-l_at_freelists.org
Subject: default constraint updating existing rows

Hi,

We are adding a column with default constraint and we only want it to apply to new rows but it is updating existing rows even though column allows null. I am using the following test:

SQL> create table test (a int);

Table created.

SQL> insert into test values(1);

1 row created.

SQL> insert into test values(2);

1 row created.

SQL> alter table test add b int default 3;

Table altered.

SQL> select * from test;

         A B
---------- ----------

         1          3
         2          3

SQL> desc test
 Name                                      Null?    Type
 ----------------------------------------- -------- --------------

 A                                                  NUMBER(38)
 B                                                  NUMBER(38)

Is there any way to add new column with default constraint without updating existing rows?

Thanks
--Harvinder

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http://www.freelists.org/webpage/oracle-l Received on Tue Dec 16 2008 - 14:24:42 CST