Re: [PHP] Re: About XSLT/XML Pagination


""Nathan Nobbe"" <quickshiftin@xxxxxxxxx> wrote in message
news:7dd2dc0b0707221103x7e8c7c8dw9439ab5fd0801c55@xxxxxxxxxxxxxxxxx
thanks for your reply tony.
i started reading about xsl almost 2 years ago, but only started
experimenting using it in conjuction w/
php about 6 months ago, so im quite new to it still.
the greatest thing ive learned from your articles so far is a
modularization
approach for the xsl files.
my first attempt is pretty pathetic, i have just one xsl file per page,
and
since the pages generally look
the same each xsl file has a large amount of overlapping code.

Every programming language, including XSL, has the ability to take common
code and put it in a subroutine so that it can be written just once and
referenced many times instead of being duplicated every time. Once you know
that in XSL these "subroutines" are called "templates" the rest is easy.

i knew there
was a way to avoid this,
but i wasnt sure how until you hopped on the list and pointed us to your
articles and framework.
though ive been busy with other things im looking forward to getting back
into xsl and doing it right.

ive also been building the xml data in memory, but the internal validation
came to mind when i started
pondering what the benefit of incorporating DTDs or XMLSchemas would be.
to
illustrate what im
imagining take some simple xml data, but imagine it has a DTD or XMLSchema
associated with it. now
as part of the process of building this xml datum in memory *the system*
would,
as a last step, validatate the
datum against its DTD or XMLSchema. the rationale here being the
structure
of the memory resident
xml may be faulty. what im going for here is a system where developers
would be given the responsibility
of wrting code that would build the xml data that would in turn be handed
to
the xslt processor.

If individual programmers wll have the responsibility of writing the code to
create their own XML documents for transformation into HTML then I would
suggest that your approach is wrong. If you look at my framework you will
see that all XML generation is performed by a single pre-written subroutine.
All the programmer has to do is ensure that the business object is populated
with the correct data and everything else is automatic. There is also no
need to write any XSL as it has already been written (and therefore tested).
That is the benefit of a well-crafted framework.

i know
we all try to do our best in life, but i imagine there would be mistakes
in
the generation of said xml data
at some point, and rather than have this impact the output of a dynamic
page
wouldnt it be better for the system
to realize an error ahead of time and handle it gracefully?

There is no point in vaidating an XML document against a DTD or XMLSchema if
the document is going to be transformed into HTML immediately after it has
been created as any mistakes will immediately be obvious in the HTML output.
Either the HTML is correct, or it is not. It is as simple as that.

--
Tony Marston
http://www.tonymarston.net
http://www.radicore.org

-nathan

On 7/22/07, Tony Marston <tony@xxxxxxxxxxxxxxxxxxxxxxxx> wrote:


""Nathan Nobbe"" <quickshiftin@xxxxxxxxx> wrote in message
news:7dd2dc0b0707220819l3ac2579aw90a8a2f9b3f1bfb1@xxxxxxxxxxxxxxxxx
Tony,

what are the trade offs between creating xml files and creating objects
in
memory to
pass to the xslt processor? if arbitrary xml data is only going to be
used
on a single
dynamic page, then is it necessary to create a file?

Although I say XML file I actually build and process it in memory. I only
write a copy to disk for debugging purposes. The contents of the file (or
document) is the same wherever it exists.

also, is there any reason to leverage the validation features of xml
while
building a dynamic page? for instance assume data was drawn from a
database to create 1 or more xml files. would it make sense to
validate
those new xml files prior to invoking the xslt processor, and
optionally
not invoke the transformation process if the xml data is found to be
invalid?

This would be overkill. If you are going to build and consume an XML
document yourself there is no point in validating it. Remember that XML
was
originally designed as a format for data interchange, so validation is
only
necessary when you receive an XML document from a third party.

--
Tony Marston
http://www.tonymarston.net
http://www.radicore.org

thanks,

-nathan

On 7/22/07, Tony Marston <tony@xxxxxxxxxxxxxxxxxxxxxxxx> wrote:

You misunderstand that article. All pagination is done within the
program
code in order to construct the SQL query with the relevant LIMIT and
OFFSET
values. The entire result set is then extracted from the database and
written to an XML file, and the XSL transforms the whole XML file into
a
single HTML document, after which the XML document is discarded. The
HTML
document contains hyperlinks which allow the user to select the number
of
rows per page and the desired page number and these selections are
processed
within the PHP code. There is no process which goes back to the
previous
XML
file to extract just a subset of the rows that need to be displayed as
each
page is extracted directly from the database.

--
Tony Marston
http://www.tonymarston.net
http://www.radicore.org

"Kelvin Park" <kelvinpark86@xxxxxxxxx> wrote in message
news:46A3180B.3020900@xxxxxxxxxxxx
http://www.tonymarston.net/php-mysql/xsl.html#a1
This site generally explains how pagination is done with xslt and
xml.
However it does not fully explain how to paginate the data when a
certain
number of rows are printed.
For example, it wouldn't make another page after 100 item names were
printed out where total there are 1000 items that need to be printed
out,
making it total 10 pages.
Do you know what should be added in order to make it work?

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