Re: Regarding NOT NULL Option for Table Fields....
Hi ashok,
With check, you could do iy, but they don't work with mysql.
The only solution i ican see is an application control or :
drop table if exists tempo;
create table tempo like mine;
insert into tempo values('','');
insert into mine select * from tempo where length(...)0;
drop table tempo;
Mathias
Selon Ashok Kumar [EMAIL PROTECTED]:
hi Mathias,
My question is how can i protect the empty strings
(that contains length 0).
thanks and regards,
Ashok Kumar.P.S.
--- [EMAIL PROTECTED] wrote:
Hi,
'' or empty string is not a null in mysql. This is
true for Oracle !
this simple test lets you understand :
* Without NULLs
mysql create table notnull (t varchar(10) NOT
NULL);
Query OK, 0 rows affected (0.14 sec)
mysql insert into notnull values('test1');
Query OK, 1 row affected (0.01 sec)
mysql insert into notnull values('');
Query OK, 1 row affected (0.02 sec)
mysql insert into notnull values(NULL);
ERROR 1048 (23000): Column 't' cannot be null
mysql select * from notnull;
+---+
| t |
+---+
| test1 |
| |
+---+
2 rows in set (0.02 sec)
mysql select * from notnull where isnull(t);
Empty set (0.02 sec)
* With NULLs
mysql create table isnulle(a varchar(10));
Query OK, 0 rows affected (0.08 sec)
mysql insert into isnulle values(NULL);
Query OK, 1 row affected (0.03 sec)
mysql select * from isnulle where isnull(a);
+--+
| a|
+--+
| NULL |
+--+
1 row in set (0.00 sec)
Hope that helps.
Mathias
Selon Ashok Kumar [EMAIL PROTECTED]:
Hi friends,
I'm having one doubt on NOT NULL specification
for
the table field properties. That is i have created
on
table-mine which contains name(Not Null) and
pwd(Not
Null). Now I intended to execute the following
query.
insert into mine values('','')
This means that i'm trying to insert the null
fields
to the table. but this query is successfully
executed
and 1 row is inserted into table with empty
values.
why it's happening and how can i resolve this
problem.
Pls give me suggestions regarding this.
Thanks and Regards,
Ashok Kumar.P.S
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Re: Regarding NOT NULL Option for Table Fields....
Ashok Kumar wrote:
Hi friends,
I'm having one doubt on NOT NULL specification for
the table field properties. That is i have created on
table-mine which contains name(Not Null) and pwd(Not
Null). Now I intended to execute the following query.
insert into mine values('','')
This means that i'm trying to insert the null fields
to the table. but this query is successfully executed
and 1 row is inserted into table with empty values.
why it's happening and how can i resolve this problem.
Pls give me suggestions regarding this.
Thanks and Regards,
Ashok Kumar.P.S
Because '' is an empty string, not NULL.
Michael
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Re: Regarding NOT NULL Option for Table Fields....
Hi,
'' or empty string is not a null in mysql. This is true for Oracle !
this simple test lets you understand :
* Without NULLs
mysql create table notnull (t varchar(10) NOT NULL);
Query OK, 0 rows affected (0.14 sec)
mysql insert into notnull values('test1');
Query OK, 1 row affected (0.01 sec)
mysql insert into notnull values('');
Query OK, 1 row affected (0.02 sec)
mysql insert into notnull values(NULL);
ERROR 1048 (23000): Column 't' cannot be null
mysql select * from notnull;
+---+
| t |
+---+
| test1 |
| |
+---+
2 rows in set (0.02 sec)
mysql select * from notnull where isnull(t);
Empty set (0.02 sec)
* With NULLs
mysql create table isnulle(a varchar(10));
Query OK, 0 rows affected (0.08 sec)
mysql insert into isnulle values(NULL);
Query OK, 1 row affected (0.03 sec)
mysql select * from isnulle where isnull(a);
+--+
| a|
+--+
| NULL |
+--+
1 row in set (0.00 sec)
Hope that helps.
Mathias
Selon Ashok Kumar [EMAIL PROTECTED]:
Hi friends,
I'm having one doubt on NOT NULL specification for
the table field properties. That is i have created on
table-mine which contains name(Not Null) and pwd(Not
Null). Now I intended to execute the following query.
insert into mine values('','')
This means that i'm trying to insert the null fields
to the table. but this query is successfully executed
and 1 row is inserted into table with empty values.
why it's happening and how can i resolve this problem.
Pls give me suggestions regarding this.
Thanks and Regards,
Ashok Kumar.P.S
__
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Stay in touch with email, IM, photo sharing and more. Check it out!
http://discover.yahoo.com/stayintouch.html
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To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
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