sqlobject-discuss

[SQLObject] Default value

[Hong Y. <ob...@21...>]

Hi,

I have a field in a PostgreSQL database table for which I would like the 
database to calculate the default value. The field itself is declared as 
NOT NULL DEFAULT (some function)

When defining the SQLObject class, if I use

  field = Col()

and then try to create an item I get the error that the field must have 
a value.

If I use instead:

  field = Col(default=None)

I am not required to give a value but it is translated into INSERT ... 
SET FIELD VALUE NULL, which is not allowed by the table definition.

How can I make SQLObject create an INSERT statement without the field 
'FIELD' so that the database will take over the calculation of the 
default value? It wouldn't make sense to duplicate the database logic of 
default value calculation in Python to be used in Col(default = ...)

Your help is appreciated.

Hong Yuan

Re: [SQLObject] Default value

[Oleg B. <ph...@ma...>]

On Fri, Dec 24, 2004 at 05:33:54PM +0800, Hong Yuan wrote:
> I have a field in a PostgreSQL database table for which I would like the 
> database to calculate the default value.

   SQLObject cannot do it yet.

Oleg.
-- 
     Oleg Broytmann            http://phd.pp.ru/            ph...@ph...
           Programmers don't die, they just GOSUB without RETURN.

Re: [SQLObject] Default value

[Stuart B. <st...@st...>]

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Hong Yuan wrote:
| Hi,
|
| I have a field in a PostgreSQL database table for which I would like the
| database to calculate the default value. The field itself is declared as
| NOT NULL DEFAULT (some function)

| I am not required to give a value but it is translated into INSERT ...
| SET FIELD VALUE NULL, which is not allowed by the table definition.
|
| How can I make SQLObject create an INSERT statement without the field
| 'FIELD' so that the database will take over the calculation of the
| default value? It wouldn't make sense to duplicate the database logic of
| default value calculation in Python to be used in Col(default = ...)

This works for PostgreSQL (and should for all ANSI complient databases).
First, define this small helper:

class Default(object):
~    def __sqlrepr__(self, dbName):
~        return "DEFAULT"
DEFAULT = Default()


Then define your field as:

~    field = Col(default=DEFAULT)

- --
Stuart Bishop <st...@st...>
http://www.stuartbishop.net/
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