Posted by Jerry Stuckle on 01/18/08 01:33

KDawg44 wrote:
> On Jan 17, 7:14 pm, Jerry Stuckle <jstuck...@attglobal.net> wrote:
>> KDawg44 wrote:
>>> Hi,
>>> I have a feeling this is a dumb question, but I am exploring AJAX and
>>> PHP. I would like to write my PHP in an Object Oriented approach.
>>> What is the limitation on what I can return in AJAX? Every example I
>>> find seems to be text, which make sense because it is client side.
>>> So, if I want to try to separate the presentation from the
>>> application, I should call a PHP script using AJAX, and in that PHP
>>> script have objects, call the objects methods and which return to the
>>> PHP script, which returns it to the AJAX script.
>>> So, how do I keep persistent objects throughout the application? Will
>>> each PHP call instantiate a new session or new version of the PHP
>>> script or can I simply put the objects in the $_SESSION?
>>> Thanks for your help as I try to learn/understand this.
>>> Kevin
>> Kevin,
>>
>> Web pages are transaction oriented. Every call to a web page, whether
>> it be via AJAX or a browser request, is a new transaction, and has
>> nothing in it other than what the browser sends.
>>
>> Typically in web programming, you do not keep persistent objects
>> throughout the run. Rather, you create them as needed.
>>
>> Two ways to keep track of things - store things in a cookie (typically
>> small amounts of text data on the browser) or in the session (text or
>> binary data). But either way, you don't want to store large amounts of
>> data, for performance reasons.
>>
>> You can put objects in the session, as long as they don't contain
>> resources. But if there is a large amount of data, i.e. from a
>> database, it's generally better to keep a key in the session and
>> retrieve the data when it is required.
>> --
>> ==================
>> Remove the "x" from my email address
>> Jerry Stuckle
>> JDS Computer Training Corp.
>> jstuck...@attglobal.net
>> ==================
>
> Jerry,
>
> Thanks so much for your responses. You are always such a helpful
> resource. I understand OO programming but as a young professional
> (whose mainstay is sys admin and network engineering and not
> programming) unfortunately putting it into practice with databases is
> something i have not really done and using OO concepts in web
> programming I have not done at all.
>
> So the best bet, if I understand you clearly, is to create a hash
> table with a key and some data (whatever the primary key in the DB is
> maybe?) that allows me to quickly pull that data from the DB again and
> load it back in to the PHP object?
>
> Thanks for the help.
>

That's what I generally do. But no need to create a hash value. Each
table should already have a primary key (typically an automatically
numbered column) which is all you need to identify the data. Just pass
that in the $_SESSION, i.e. as $_SESSION['datakey'];

Transactional programming is quite a bit different from what most
programmers are used to.

--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
jstucklex@attglobal.net
==================

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