[database] [Database] Toward better databases

[Barry Jaspan]

David,

On Jul 7, 2008, at 11:02 PM, David Timothy Strauss wrote:
> MySQL requires non-null defaults for non-null columns. What's the  
> problem?

Ummmm.. really?  My understanding is that MySQL provides implicit  
default values for NOT NULL columns that are not given a default value  
when not in strict mode, but that isn't the same as requiring that a  
non-null default be provided.

During the D6 switch to Schema API, I tried to remove all the  
unnecessary/incorrect default values on columns.  For the variable  
table, a default name of '' is semantically ridiculous; we should  
never have a variable whose name is the empty string and there should  
never be an INSERT statement into that table that does not provide a  
value for name.  So why have the default value at all?

Barry



>
>
> ----- "Joshua D. Drake" <jd at commandprompt.com> wrote:
>
>> On Mon, 2008-07-07 at 20:42 -0500, Larry Garfield wrote:
>>> On Monday 07 July 2008 8:44:40 am you wrote:
>>>> Howdy, everyone.  Here's my current brain-dump:
>>
>>> CREATE TABLE variable (
>>> 	name varchar(128) NOT NULL default '',
>>> 	value text NOT NULL,
>>> 	PRIMARY KEY (name)
>>> )
>>>
>>
>> I would also note that the above is horribly bad.
>>
>> You just said that your primary key is name but that its default is
>> '',
>> that protects against NOT NULL but allows a single '' as well as a
>> single ' ' or '  ' or '    ' etc...
>>
>> Sincerely,
>>
>> Joshua D. Drake
>>
>>
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