Re: [sqlite] Specifying a nullable column

[Paul Medynski]

On 12-Jun-2012 08:08, Richard Hipp wrote:

On Tue, Jun 12, 2012 at 7:04 AM, Paul Medynski  wrote:


Hi Kevin,

I understand the 'NOT NULL' column constraint and the syntax diagram and
text describe it quite well.  What isn't described is whether or not
specifying simply 'NULL' is truly supported.  For example, the following
create table statement is accepted by SQLite and appears to behave as
expected (column 'Id' is not null and column 'Name' is nullable):

create table
(
  Id integer not null,
  Name   text null
);

I would like to know if 'NULL' is meant to be a valid column constraint or
not.  It seems to work, but the documentation doesn't mention it explicitly.


The NULL constraint is parsed and then ignored.
http://www.sqlite.org/src/artifact/f29df90bd3a?ln=299


Perfect!  Thanks Richard.

-Paul


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Re: [sqlite] Specifying a nullable column

[Richard Hipp]

On Tue, Jun 12, 2012 at 7:04 AM, Paul Medynski  wrote:

> Hi Kevin,
>
> I understand the 'NOT NULL' column constraint and the syntax diagram and
> text describe it quite well.  What isn't described is whether or not
> specifying simply 'NULL' is truly supported.  For example, the following
> create table statement is accepted by SQLite and appears to behave as
> expected (column 'Id' is not null and column 'Name' is nullable):
>
> create table
> (
>  Id integer not null,
>  Name   text null
> );
>
> I would like to know if 'NULL' is meant to be a valid column constraint or
> not.  It seems to work, but the documentation doesn't mention it explicitly.
>

The NULL constraint is parsed and then ignored.
http://www.sqlite.org/src/artifact/f29df90bd3a?ln=299


>
> Thanks,
> -Paul
>
>
>
>
> On 11-Jun-2012 15:35, Kevin Benson wrote:
>
>> On Mon, Jun 11, 2012 at 10:35 AM, Paul Medynski
>>  wrote:
>>
>>  Hi folks,
>>>
>>> I notice that the syntax diagram for 'create table' shows the
>>> 'column-constraint' definition as requiring 'null' to always be preceded
>>> by
>>> 'not'.  I don't see any definition that supports just 'null'.  However,
>>> when using SQLite3 3.7.3 or 3.7.9, I can create a table and specify any
>>> column as "Foo  null", and it works as expected allowing the column
>>> to contain null values.
>>>
>>> Is the syntax diagram simply out of date, or am I doing something that
>>> appears to work, but will bite me in the end? :)
>>>
>>>  
>>> http://www.sqlite.org/draft/**lang_createtable.html
>>
>> "A CREATE TABLE command specifies the following attributes of the new
>> table:
>> -
>> -
>> -
>> -
>> - A default value or expression for each column in the table.
>> -
>> -
>> - A set of SQL constraints for each table. SQLite supports UNIQUE, NOT
>> NULL, CHECK and FOREIGN KEY constraints."
>>
>> "A table created using CREATE TABLE AS has no PRIMARY KEY and no
>> constraints of any kind. The default value of each column is NULL."
>>
>> --
>>--
>>   --
>>  --Ô¿Ô--
>> K e V i N
>> __**_
>> sqlite-users mailing list
>> sqlite-users@sqlite.org
>> http://sqlite.org:8080/cgi-**bin/mailman/listinfo/sqlite-**users
>>
>
> --
>
> --**--
> Paul Medynski BlackBerry Messenger Group
> Senior Software Developer Research In Motion
> pmedyn...@rim.com50 Innovation Drive
> Phone:  +1 902 982 6134  Bedford, NS
> Fax:+1 902 482 4380  B4B 0G4
>
>
> __**_
> sqlite-users mailing list
> sqlite-users@sqlite.org
> http://sqlite.org:8080/cgi-**bin/mailman/listinfo/sqlite-**users
>



-- 
D. Richard Hipp
d...@sqlite.org
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Re: [sqlite] Specifying a nullable column

[Paul Medynski]

Hi Kevin,

I understand the 'NOT NULL' column constraint and the syntax diagram and 
text describe it quite well.  What isn't described is whether or not 
specifying simply 'NULL' is truly supported.  For example, the following 
create table statement is accepted by SQLite and appears to behave as 
expected (column 'Id' is not null and column 'Name' is nullable):


create table
(
  Id integer not null,
  Name   text null
);

I would like to know if 'NULL' is meant to be a valid column constraint 
or not.  It seems to work, but the documentation doesn't mention it 
explicitly.


Thanks,
-Paul



On 11-Jun-2012 15:35, Kevin Benson wrote:

On Mon, Jun 11, 2012 at 10:35 AM, Paul Medynski  wrote:


Hi folks,

I notice that the syntax diagram for 'create table' shows the
'column-constraint' definition as requiring 'null' to always be preceded by
'not'.  I don't see any definition that supports just 'null'.  However,
when using SQLite3 3.7.3 or 3.7.9, I can create a table and specify any
column as "Foo  null", and it works as expected allowing the column
to contain null values.

Is the syntax diagram simply out of date, or am I doing something that
appears to work, but will bite me in the end? :)


http://www.sqlite.org/draft/lang_createtable.html

"A CREATE TABLE command specifies the following attributes of the new table:
-
-
-
-
- A default value or expression for each column in the table.
-
-
- A set of SQL constraints for each table. SQLite supports UNIQUE, NOT
NULL, CHECK and FOREIGN KEY constraints."

"A table created using CREATE TABLE AS has no PRIMARY KEY and no
constraints of any kind. The default value of each column is NULL."

--
--
   --
  --Ô¿Ô--
 K e V i N
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--


Paul Medynski BlackBerry Messenger Group
Senior Software Developer Research In Motion
pmedyn...@rim.com50 Innovation Drive
Phone:  +1 902 982 6134  Bedford, NS
Fax:+1 902 482 4380  B4B 0G4

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Re: [sqlite] Specifying a nullable column

[Kevin Benson]

On Mon, Jun 11, 2012 at 10:35 AM, Paul Medynski  wrote:

> Hi folks,
>
> I notice that the syntax diagram for 'create table' shows the
> 'column-constraint' definition as requiring 'null' to always be preceded by
> 'not'.  I don't see any definition that supports just 'null'.  However,
> when using SQLite3 3.7.3 or 3.7.9, I can create a table and specify any
> column as "Foo  null", and it works as expected allowing the column
> to contain null values.
>
> Is the syntax diagram simply out of date, or am I doing something that
> appears to work, but will bite me in the end? :)
>
http://www.sqlite.org/draft/lang_createtable.html

"A CREATE TABLE command specifies the following attributes of the new table:
-
-
-
-
- A default value or expression for each column in the table.
-
-
- A set of SQL constraints for each table. SQLite supports UNIQUE, NOT
NULL, CHECK and FOREIGN KEY constraints."

"A table created using CREATE TABLE AS has no PRIMARY KEY and no
constraints of any kind. The default value of each column is NULL."

--
   --
  --
 --Ô¿Ô--
K e V i N
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