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Posted by Steve on 01/18/08 22:54
"Gary L. Burnore" <gburnore@databasix.com> wrote in message
news:fmr8f4$gqf$1@blackhelicopter.databasix.com...
> On Fri, 18 Jan 2008 15:45:52 -0600, Michael Austin
> <maustin@firstdbasource.com> wrote:
>
>>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)
>
> Maybe he meant it only takes an as400 to bog a mainframe? Heh.
exactly. :)
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