[Dbix-class] Re: '' != NULL for great sadness

[Ryan Cone]

On Jul 9, 2009, at 9:21 PM, fREW Schmidt wrote:
> Anyway, I'm reading up on what another poster said about nulls in  
> the db.  So far I'm not convinced, but give me a while to read up on  
> some of this stuff.  I'd appreciate any other, more complete links  
> relating to nulls in the database.
>
> It just seems to me that it make sense to have undefined values in a  
> field, but I need to think through that some more.
>

Both sides of this allow/disallow NULL issue are well represented  
online.  I find that we generally pick one camp to fall into and  
rationalize our choices accordingly.

For what it's worth, here is my rationalization...When using any ORM,  
I strive to create data objects that closely resemble my programmed  
ones.  When I find myself "needing" a NULL, it often means I have not  
really defined my class properly.

 From your original example you defined QCParts as having Fixtures.

If a QCPart can exist without a Fixture, then the Fixture does not  
belong in the QCPart class.  And you might need q_c_part_id in  
Fixtures or a Fixtures_QCParts table depending on the reverse  
relationship.

If a QCPart cannot exist without a Fixture, then it seems that it  
should not be allowed to be unknown but may be allowed to be undefined- 
because per Darren Duncan's suggestion.

-Ryan