OK,

Are there a solution to I create a new database using the metadata of my
actual database setting the NOT NULL and defining the default = ''
(empty strings) ???
And how can I migrate the data from my old database (where I can have
null strings) to my new database (where I couldn't have null string)
setting the null string fields to empty strings ''?

Thanks again

Fabrício
-----Mensagem original-----
De: firebird-support@yahoogroups.com
[mailto:firebird-support@yahoogroups.com] Em nome de Jason Dodson
Enviada em: terça-feira, 10 de janeiro de 2006 11:38
Para: firebird-support@yahoogroups.com
Assunto: Re: RES: RES: [firebird-support] String Concatenation with null
field


A rule of thumb that I always follow... never allow a string field to be
null.
Simple. Your alternative is to either coalesce NULLS into something
meaningful
to you (most likely '') or in your where clauses have "Where myfield is
not null
and myfield <> ''".

Having a field ALLOWED to be NULL is simply a referential shortcut
anyway. It
saves you from having a linking table and a join. NULL implies that if
you did
use a linking table, it wouldn't join at that field (just like you would
get a
null with a left join).

Jason

Fabrício Fadel Kammer wrote:

> Hi Helen,
>
> I agree with you, but I've a lot of clients using my software and the
> NULL string field was not important when the software was developed.
> I'll have a lot of work and perhaps problems with validations if I

alter

> my database defining all string fields as NOT NULL and the default

value

> as a empty string.
>
> If I alter the database I'll need to import the actual database to a

new

> and do the validations of null fields.... It'll give me a lot of work!
>
> I stay surprise with this because it doesn't occour in Oracle

databases.

>
> Thanks
>
> Fabrício F. Kammer

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