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Posted by Michael Austin on 01/18/08 21:45
Steve wrote:
> "Gary L. Burnore" <gburnore@databasix.com> wrote in message
> news:fmr27l$666$4@blackhelicopter.databasix.com...
>> On Fri, 18 Jan 2008 20:51:38 +0100, "Rik Wasmus"
>> <luiheidsgoeroe@hotmail.com> wrote:
>>
>>> On Fri, 18 Jan 2008 20:46:01 +0100, Michael Austin
>>> <maustin@firstdbasource.com> wrote:
>>>
>>>> Gary L. Burnore wrote:
>>>>> [Carolyn's post left intact and comp.lang.php added]
>>>>> On Fri, 18 Jan 2008 09:27:47 -0500, Carolyn Marenger
>>>>> <cajunk@marenger.com> wrote:
>>>>>
>>>>>> I am new to PHP/MySQL. I would like some of your thoughts on when to
>>>>>> use php code and when to use mysql queries.
>>>>>>
>>>>>> In the case I am working on, a learning project for myself, I am
>>>>>> writing a contact management application. Basically a phone book
>>>>>> with a many to many relationship between individuals and
>>>>>> organizations, and one to many between individuals/organizations and
>>>>>> the relevant data such as phone numbers.
>>>>>>
>>>>>> I am working on a page which lists all the individuals. I have a
>>>>>> horizontal listing at the top containing all the unique surname
>>>>>> initials, which link to headings as the list progresses. ie:
>>>>>>
>>>>>> -----
>>>>>> A B N
>>>>>>
>>>>>> A
>>>>>> Abnew, Georgina
>>>>>> Adwit, Dave
>>>>>>
>>>>>> B
>>>>>> Biltmore, Garth
>>>>>>
>>>>>> N
>>>>>> Niles, Paulina
>>>>>> Norton, Alicia
>>>>>> -----
>>>>>>
>>>>>> Currently, I have MySQL select all the unique initials and process
>>>>>> that into an array. The array is dumped to the screen as the index at
>>>>>> the top. Next the array is used for MySQL selects of surnames with
>>>>>> that initial.
>>>>>>
>>>>>> In the above example that would result in 6 MySQL queries. Assuming
>>>>>> only English based names, no foreign character sets, no numbers, no
>>>>>> symbols, that would result in a maximum of 27 queries.
>>>>>>
>>>>>> I could rewrite the PHP code to select all the names in a single query
>>>>>> . Then use PHP to process the list to make the index, headings, and
>>>>>> list the names.
>>>>>>
>>>>>> For a small private phone book, either way, so what - big deal. In a
>>>>>> public database, there could conceivably be a large amount of network
>>>>>> overhead processing the Mysql queries. However, from the reading I
>>>>>> have been doing, MySQL is very fast, PHP being interpreted, may end up
>>>>>> being slower.
>>>>>>
>>>>>> So, anyone care to enlighten me? I would love your thoughts,
>>>>>> comments, experiences.
>>>>>>
>>>>> I've added the crosspost because I believe this is an extremely good
>>>>> question that doesn't get the attention it deserves. You should get a
>>>>> lot of opinions on this.
>>>>> Here's mine:
>>>>> One query to sql is better than 6 and it's certainly better than 27.
>>>>> PHP could process the list quite quickly. If your DB is on a
>>>>> different server than your web site (good practice to keep your DB
>>>>> behind a firewall>, then you're crossing your network up to 27 times
>>>>> instead of just once.
>>>> I would agree that this may work in this one situation, however, when
>>>> those datasets get too large - with large numbers of request for that
>>>> data, you can do more harm than good.
>>>>
>>>> I recently fixed some code that was causing over 400MB per request to be
>>>> returned for processing - and literally crippled an IBM mainframe. to
>>>> the point that once we shut off the web app - it took the frame more
>>>> than 7 hours to catch up on it's batch processing. One of those - let's
>>>> let the application process the data. Again, in a very small number of
>>>> situations this **may** be okay, in others, it can be crippling.
>>>>
>>>> Things to remember:
>>>> 1) KNOW YOUR DATA - what it is and how much you have.
>>>> 2) KNOW YOUR "customer" - how many, how they might use the data.
>>>> 3) Your "customer" will ALWAYS use your application in ways you never
>>>> dreamed of...
>>> 4) Never ask for more data then you're really sure you're going to use.
>>> The numerous times I've seen 'SELECT *' in production code...
>> Right. As I read her example, she planned on using the data, but
>> parsing it out up to 27 ways. (& btw, we all know how little it
>> takes to bog an IBM mainframe) :)
>
> can you say, as400? :^)
>
>
Sorry, but an AS400 is a LONG way from being a mainframe... (ie 360/390)
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