Re: [chiPHPug-discuss] Data Models

[CM L. <cmc...@gm...>]

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Mudslinging is pointless.

What Anacreo proposes requires that the "schema" be handled by the
script rather than the database (a more traditional schema). There's
certainly cases where that could be useful, in the same way that there
are cases where Google's file system makes sense. I think we can agree
that it's not a common design and probably wouldn't be needed for small
to medium scale projects.

I do see large similarities with document oriented databases, but
Anacreo's proposition has the added benefit of proper foreign keys
(though replication/horizontal scaling is, of course, more difficult).
In any event, it's just a different, specialized tool and I appreciate
hearing the thought (though I don't appreciate the derisive comments
Anacreo's made.)

Back to junkmail's question about user-created fields:
I've seen two options:

First, the PHP serves more or less as a front for ALTER TABLE ADD COLUMN
x commands (with checks for column name length, uniqueness, etc).
Whenever such a column is added, an entry in a "field list" table is
also inserted so that, whenever loading a model of that type, the extra
fields are also grabbed. With proper caching this query-per-instance can
be avoided almost all together.

Second, a table serves as the "custom fields" table, with a column for
associated model, a column for field name, and a column for value. This
is used by Trac (ticket management software) for example, and either
requires a left join for each additional field (obviously taxing), code
that is smart enough to handle the duplicate data returned by a single
left join (somewhat complex), or two separate queries (one for the
model's base data and one for the custom field data). If you go the
"custom fields" table route, I'd highly suggest you use multiple "value"
columns, one for each type and/or foreign key (i.e. value_int,
value_varchar, etc.), otherwise the "value" column has to be the most
generic of the types you put in to it (often becoming a text field),
which is highly inefficient, difficult to compare, etc.

Best of Luck,
CM Lubinski
- ---
http://cmlubinski.info


matt donohue wrote:
> I'm missing the simple in your explanation or the reality of 3000 columns (Seriously???).
> Do you project the schema on the side of buildings? 
> 
> 
> 
> ________________________________
> From: Anacreo <an...@gm...>
> To: Chicago PHP User Group <chi...@li...>
> Sent: Tue, April 20, 2010 8:40:23 PM
> Subject: Re: [chiPHPug-discuss] Data Models
> 
> Yeah I don't have time for this...  I've received similar poo poo
> responses from this group on similar type discussions.
> 
> I'll tell you I'm a performance EXPERT and have been designing large
> scale systems for over 15 years.
> 
> The general arguments have always been that the approach is too simple
> or too not what you guys are doing.  Try working on a large scale and
> you'll realize ruby on rails and PHP with training wheels isn't quite
> the only answer.
> 
> As for arbitrary numbers its not so arbitrary your code should meet
> your demands.  When I signed up I didn't realize this group was PHP
> for pea-pod size projects with a pea-pod brained Arlo.
> 
> Alec
> 
> On 4/20/10, matt donohue <mm_...@ya...> wrote:
>> I'm resisting the urge to respond to this... or the 3000 columns.
>>
>>
>>
>> ________________________________
>> From: Steve Gadlin <sg...@wc...>
>> To: Chicago PHP User Group <chi...@li...>
>> Sent: Tue, April 20, 2010 4:40:22 PM
>> Subject: Re: [chiPHPug-discuss] Data Models
>>
>> I'm a big fan of one table design.  When I need a second table, I often
>> create an entirely separate database for it, just to keep things separate.
>> I don't like it when my tables "touch."  Viruses spread easier when they do.
>>
>> Hi Arlo.
>>
>> Steve
>>
>>
>> On 4/20/10 4:37 PM, "Arlo Leach" <ar...@ar...> wrote:
>>
>>>> I wasn't being sarcastic at all Arlo I was giving you a design pattern
>>>> for
>>>> working with very large customizeable and extensible data set, sorry if
>>>> you
>>>> can't wrap your head around this design.
>>>
>>> Well ... sure, I can wrap my head around it, but all the superlatives like
>>> "wonderful," "fascinating," "brilliant" and "fun" plus the arbitrary,
>>> large
>>> numbers and the generality of your "elements" example made it sound like a
>>> joke ... my mistake then. The Onion video is still funny, though.
>>>
>>> Cheers,
>>> -Arlo
>>>
>>> _______________________________
>>>
>>> Arlo Leach
>>> 773.769.6106
>>> http://arlomedia.com
>>>
>>> The killer app for the iPad
>>> http://washboardapp.com
>>>
>>>
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>>> chi...@li...
>>> https://lists.sourceforge.net/lists/listinfo/chiphpug-discuss
>> --
>> Steve Gadlin
>> Web Development Manager
>> Weigel Broadcasting
>> 312.660.8375
>> sg...@wc...
>>
>>
>>
>>
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> 
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