Empty string in NOT NULL column

I'm migrating data to Oracle 9i from a database engine that supports emtpy strings in column with NOT NULL specified in the DDL. I would have thought Oracle would support this, but any attempt to put empty string data into a column created with NOT NULL is returning a 'column does not support nulls'-type error.
Is there an option to allow this, or does Oracle simply not support this and assumes blank is null?
Thanks

I would have thought Oracle would support this, but any attempt to put empty string data into a column created with NOT NULL is returning a 'column does not support nulls'-type error.In Oracle Null means null nothing not even an empty String.
Yes DB's like Ingress supports this. But I think Oracle is right.
Is there an option to allow this, or does Oracle simply not support this and assumes blank is null?I am not aware of any options as it is against the basic principles.
you can find work arounds to do the migration. But storing a blank NO.
Good Luck
Vij

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Problem: textbox leave empty string("") instead of null

Hello, I have a problem with textboxes. By default, they always are initialized to null, but when I start entering and removing data from textboxes, many times they leave an empty string "" instead of null.
And, of course, it's not the same a null value as an empty string and thus, I haven't got the expected result in queries to database.
Thus, I always have to compare textbox values with "" and null. It's very tedious and not elegant solution. I would like to know if there is another way to get the values as null instead of empty strings.

Yes. Once you entered and remove the text it will evaluated as you told .
For ur case u can Try the condition as
if ( instance !=null && instance.length !=0)
be sure instance != null check b4 other wise u can get NullPointerException

Oracle BPEL - Does not cater for not null columns and use of "default".

Oracle BPEL - Does not cater for not null columns and use of "default".
BPEL fails with message:
ORA-01400: cannot insert NULL into ("EDDB"."SEISMIC_LINES"."COORD_SYSTEM_ID")
But SQL*PLUS command works:
INSERT into EDDB.SEISMIC_LINES
(etc)
regards
Allan Ford
Analyst / Programmer - IT Application Services, IT Services, Shared Business Services
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note: BPEL keeps it's own "offline" copy of table and database items. A column that is marked not null in the database can be marked as nullable in this area. (if you kmow that a trigger is going to cater for this ..)
One workaround is to use a trigger to provide value rather than use the column default ..

ORA-01400 - not null column with default value and item with authorization

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I should add - I guess I can always put my own custom process in to replace the DML. Just seems like a simple thing - if the value doesn't appear on the debug, isn't set with any default value... don't include it in the DML.

Do we have a function in oracle to select not null columns at the begining

Hi,
I have 8 columns. Some of them might be null.
I want to display all 8 columns in my result. Not null columns will be first and null at the end.
Here is a sample data :
Employee table :
Employee_id   Emp_fname emp_lname emp_mname dept salary emp_height emp_weight
   1               aaa        ddd                d1   100      6           180
   2               bbb                ccc             120                 169
   3               dfe                           d2            5.9         223The expected result is :
result1 result2   result3 result4 result5 result6 result7 result8
1        aaa        ddd     d1       100     6        180
2        bbb        ccc     120      169
3        dfe        d2      5.9      223Thanks.
Edited by: BluShadow on 12-Jul-2012 16:12
added {noformat}{noformat} tags for readability. Please read {message:id=9360002} and do this yourself in future.

The requirement doesn't make a lot of sense and tends to imply that you have an incorrect data model. If that's the case, you'd be much better off fixing the data model than in trying to write this sort of query (particularly since a poor data model is going to force you to write a bunch of creative SQL).
If you define a type and a function
CREATE TYPE num_tbl AS TABLE OF NUMBER;
create or replace function count_null( l_nums in num_tbl )
return number
is
l_cnt integer := 0;
begin
for i in 1..l_nums.count
loop
    if( l_nums(i) is null )
    then
      l_cnt := l_cnt + 1;
    end if;
end loop;
return l_cnt;
end;Then you can do something like this
SQL> ed
Wrote file afiedt.buf
1 select product,
2         coalesce( q1, q2, q3, q4 ) col1,
3         (case when count_null( num_tbl( q1 ) ) = 0
4               then coalesce( q2, q3, q4 )
5               when count_null( num_tbl( q1, q2 ) ) = 1
6               then coalesce( q3, q4 )
7               when count_null( num_tbl( q1, q2, q3 ) ) = 1
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12               then coalesce( q3, q4 )
13               when count_null( num_tbl(q1, q2, q3) ) = 1
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15               else null
16           end) col3,
17         (case when count_null( num_tbl( q1, q2, q3 ) ) = 0
18               then q4
19               else null
20           end) col4
21*   from saleshist
SQL> /
PRODUCT                              COL1       COL2       COL3       COL4
Oracle EE                             100        123        128
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Script to add not null columns to all tables in database

Hello,
I need to add 5 not null columns to my existing database (all tables).
The problem is that i do not want to loose the current data.
I need a script so that i need not do this manually for each table.
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Vishal

Hello,
I need to add 5 not null columns to my existing database (all tables).
The problem is that i do not want to loose the current data.
I need a script so that i need not do this manually for each table.
Can u suggest?
Vishal I always follow this step
1) Alter table <<tablename>> add(<<columnname>> <<datatype>>)
2) Update <<tablename>> set <<columnname>>=<<anyvalue>>
3) Alter table <<tablename>> modify(<<columnname>> <<datatype>> not null)
else
1) rename <<tablename>> to <<tablenamebk>>
2) drop table <<tablename>>
3) Alter table <<tablenamebk>> add(<<columnname>> <<datatype>>)
4) update <<tablenamebk>> set <<columnname>>=<<anyvalue>>
5) create table <<tablename>> (with additional columns with not null)
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String is not null forever?

String a = "";
String b = new String();
a==null? false
b==null? false
why?

you mean a.b are Strings with length 0 but they are
exist so not equal Null?Not quite.
a and b are variables. They hold references. Those references could be null (which means they don't point to an object) but here they're not. They both point to String objects. Those String objects don't happen to contain any characters in their char arrays (the arrays themselves also exist, and have length zero), but the String objects still exist.
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Remember the finger-pointing and paper-writing examples from your other thread? Setting a reference to null is making a fist and pointing at nothing, or erasing whatever is written on a piece of paper. It has nothing to do with any objects. Setting a variable to the empty string "" is pointing your finger at a book that has only a front and back cover, but no pages inside.

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Hi,
I am trying to run a C program in which I am inserting a space character into a database table, where the column has been defined as CHAR(1) NOT NULL.
I am initialising a variable defined in C as: char, with a blank but after running the insert statement I get an error: ORA-01400: cannot insert NULL into �. .
create table nullTest ( col1 char(1) NOT NULL );
Sample code:
EXEC SQL BEGIN DECLARE SECTION;
char dbo_cValue;
EXEC SQL END DECLARE SECTION;
dbo_cValue = � �;
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INSERT
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col1
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I tried STRING and other options and I cannot get this to work.
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Thank you.

Since you did not post a sample of the code that produces an error, its hard to speculate what might be wrong with it.
But, the following sample works, and successfully inserts a space into the table.
#include <sys/types.h>
#include <stdio.h>
EXEC SQL INCLUDE SQLCA ;
EXEC SQL BEGIN DECLARE SECTION ;
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EXEC SQL END DECLARE SECTION ;
int main(void)
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Script or query to generate a report of null or not null columns

I need a script/query it should pick up all the tables from user_tab_columns and produce a report for all the tables which are the columns are null and not null.

As long as the columns were defined as NOT NULL on table create, or ALTERed NOT NULL, you can do this:
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2 FROM user_tab_columns
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DESCR                          T                              Y
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Table altered.
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2 FROM user_tab_columns
3 WHERE table_name = 'T';
COLUMN_NAME                    TABLE_NAME                     N
ID                             T                              N
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HTH
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Empty strings morphed to NULL ???

Hi all,
I am executing the following SQL-statement (short version):
statement = (OraclePreparedStatement)
connection.prepareStatement(
"INSERT INTO TEST VALUES (?)");
statement.defineColumnType(1, OracleTypes.VARCHAR);
statement.setString (1,"");
statement.execute();
statement.close();
connection.commit();
Then I have a look into the table TEST (with SQL-PLUS) and see
that my stringValue "" morphed to a NULL-value !!!
Why are "" Strings mapped to NULL ???
Is there a configuration-parameter to turn this "feature" off ???
"" is not the same as NULL, is it ???
Thank You in advance,
Ralf.
null

Ralf Severloh (guest) wrote:
: Why are "" Strings mapped to NULL ???
This is a known Oracle feature / bug (depending on your
perspective). Null strings are equal to null. Try "SELECT 1 FROM
dual WHERE '' IS NULL;" to prove it.
: Is there a configuration-parameter to turn this "feature" off
Not as far as I know.
: "" is not the same as NULL, is it ???
Not to my way of thinking, however Oracle disagrees.
--> Steve
null

NULL in not null column

Hi,
I have a table
SQL> desc tabula.M$$USERS;
Name Null? Type
USERLOGIN NOT NULL VARCHAR2(20)
PASSWORD NOT NULL VARCHAR2(30)
T$USER NOT NULL NUMBER(38)
USERNAME NOT NULL VARCHAR2(30)
USERID NOT NULL NUMBER(38)
USERGROUP NOT NULL NUMBER(38)
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password column is not null.
Application get ORA-01400 (can't insert to null into not null colum) and also when I run -
Edited by: user10237262 on Nov 29, 2011 12:54 AM

Hi welcome to forum
see below example
SQL> create table t(empno number(4) not null, ename varchar2(10))
2 /
Table created.
SQL> insert into t values(100,'abc');
1 row created.
SQL> insert into t values(200,'def');
1 row created.
SQL> insert into t values(null,'def');
insert into t values(null,'def')
ERROR at line 1:
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SQL> desc t
Name                                      Null?    Type
EMPNO                                     NOT NULL NUMBER(4)
ENAME                                              VARCHAR2(10)
SQL>"Null?" tells the perticular column is null or not...
Usage
The description for tables, views, types and synonyms contains the following information:
each column's name
whether or not null values are allowed (NULL or NOT NULL) for each column
refer:
http://docs.oracle.com/cd/B19306_01/server.102/b14357/ch12019.htm
Edited by: newbie on Nov 29, 2011 12:54 AM

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NOT NULL,
S_RECORDCREATED DATE DEFAULT (SYSDATE) NOT NULL,
S_RECORDCREATOR NUMBER (4) DEFAULT (UID) NOT NULL,
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Hi.
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Null and not null columns

Hi,
I want to specify that if an ID is 0 or null to do something... I am not sure if I am writing the code properly since it does not display anything when the coulmn has data(not null)
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do something
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do something else
<%%>
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Remember the functionality of logical OR operator. IF the first statement evaluated is TRUE, the next are not evaluated.

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hi,
I am getting the following error when i run the below query,
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ERROR at line 2:
ORA-01407: cannot update
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Query
UPDATE /*+ PARALLEL(a,6) */ master_adrs_rate_center_xref a
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SELECT /*+ PARALLEL(b,6) */
b.rate_center_nm
,b.rate_center_state_cd
,'4'
FROM
xref_temp b
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I would change your WHERE EXISTS clause to look exactly like your subquery (except for the column list of course):
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I am using Oracle 11.2, have one table tb_class as following:
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1, ,212
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Justin

Empty string in NOT NULL column

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