narasingu

 Profile Answers by narasingu 

• Jul 15th, 2008

 

No. You canot add a NULL Column. See the error below:
ERROR at line1:
ORA-01758: table must be empty to add mandatory(NOT NULL) column

rethishr

 Profile Answers by rethishr 

• Aug 1st, 2008

 

Yes But we have to Specify a Default value for the column

gtomar

 Profile Answers by gtomar 

• Aug 7th, 2008

 

Hi,

Yes you can alter table after creation for adding not null constraint.

syntax is :-

ALTER TABLE tablename

MODIFY (column name) (datatype) NOT NULL;

for eg :-

ALTER TABLE EMP

MODIFY ename VARCHAR2(10) NOT NULL

Thanks,
Gunjan

svaparna08

 Profile Answers by svaparna08 

• Oct 21st, 2008

 

We can add a not null column but it should be defaulted to some value.

kantri

 Profile Answers by kantri Questions by kantri

• Dec 16th, 2008

 

Yes, we can add a not null constraint to a column, but every row should have a data for that column.

Nattamai

 Profile Answers by Nattamai 

• Apr 7th, 2009

 

1. Create the new column
2. Insert dummy value
3. Enable the NOT NULL constraint.

MAjay

 Profile Answers by MAjay 

• Jun 6th, 2009

 

Yes

ALTER TABLE <Table Name>
MODIFY <Column Name> NOT NULL;

Ex:
ALTER TABLE scfg MODIFY scfg1 VARCHAR2(10) NOT NULL;

If you have null values in the column then you have to update all with some
default value using update script otherwise it will give you error: Null Value
Found

dj_dj_dj

 Profile Answers by dj_dj_dj 

• Jun 8th, 2009

 

Yes you can add NOT NULL column to a table that already contains data. There would not be any error such that. But only the new records inserted would be affected.

neelapu

 Profile Answers by neelapu 

• Jun 8th, 2009

 

NOT NULL constraint cannot be added at table level
To add the constraint you need to modify the column
Ex:-
ALTER TABLE emp MODIFY ename NOT NULL;

javedans

 Profile Answers by javedans 

• Jul 7th, 2009

 

1. By default you cannot add not null constraints, which already have null value in the column.
2. You need replace some dummy values to null value to meet requirement and then add constraint to that column.

Rabindra_Kumar

 Profile Answers by Rabindra_Kumar 

• Mar 20th, 2010

 

Yes a not null column can be added by using the enable novalidate option.
enable novalidate option will not validate the previous data.

ravi_oracle

 Profile Answers by ravi_oracle 

• Oct 9th, 2010

 

Hi to all..


 We can add Not NULL column to the table . But the that column must not have null value. if so u will get an error..

ORA-02296: cannot enable (Schema_name.) - null values found

So if we want to add not null columns to existed data , we must make sure that the column has no null data..


Thanks and Regards,

S.Ravi Chythanya.

kiran_marla

 Profile Answers by kiran_marla 

• Oct 9th, 2010

 

Yes, we can add not null column to table already containing data, provided that column should not contain null values.

If that colmn contains null values, then it is not possible to add constraint.

monoranjang

 Profile Answers by monoranjang 

• Jan 24th, 2011

 

Yes possible, try the below query:

ALTER TABLE test add c1 VARCHAR2(10) DEFAULT ('a') not null

Thanks

Monoranjan

Radha

• Jul 13th, 2011

 

Yes we can add NOT NULL constraint for the column already containing data
as:
If the data doesn't have null values then -
Alter table modify constraint ;
If the data contains null values then -
1)Here first to add the not null constraint with out
accepting the existing values (null values) by disable command init
Alter table modify constraint
not null disable;
2)Then the consrtaint will be enable with out validating the previous data which are nulls
Alter table enable novalidate constraint ;