I'm doing some massive (internal company) applications using PHP, which
query extensive PostgreSQL tables. This is fine, but obviously it often
requires multiple web pages to get something done. Supposedly, AJAX
promises to make web pages more interactive. But from what I understand,
I'd have to have bindings from Javascript into PostgreSQL to make this work.
Here's an example: The user wants to enter a bill (accounts payable)
into the system. He first has to pick a vendor. Normally, this would
entail a PHP page that generates a PostgreSQL query. The user would then
get a second page with various vendor information (like number of due
days for that vendor), and various other payable info. But wouldn't it
be nice to have vendor information filled in on the original page,
directly after the user picks a vendor? Theoretically, AJAX might allow
something like this. But from what I can see, it would require
PostgreSQL bindings in Javascript, and some way to pass the data back so
that PHP could use it.
Is this even possible? Is it being worked on? Is there a different
solution I don't know about? I can see where Javascript can alter the
look of a page, but I can't work out how it would allow interactive use
of a PostgreSQL table.

Paul M Foster <paulf (AT) quillandmouse (DOT) comwrites:

Here's an example: The user wants to enter a bill (accounts payable) into the
system. He first has to pick a vendor. Normally, this would entail a PHP page
that generates a PostgreSQL query. The user would then get a second page with
various vendor information (like number of due days for that vendor), and
various other payable info. But wouldn't it be nice to have vendor information
filled in on the original page, directly after the user picks a vendor?
Theoretically, AJAX might allow something like this. But from what I can see,
it would require PostgreSQL bindings in Javascript, and some way to pass the
data back so that PHP could use it.

I'd do it the reverse: Javascript would call a PHP-enabled URL, PHP would get
the data, return to JS, JS would then populate the form.

This way all your logic is contained within PG and PHP. JS would only be used
to manipulate the interface.

The way to handle this is to make your ajax call PHP scripts which
handle your data and return your XML for the Javascript (or HTML).

AJAX makes HTTP requests, it does not talk directly to the database
server.

In essence to do what you're asking you would need a JavaScript
implementation of the pgsql protocol. This would at the *very* least
make for the possibility of security issues with your database
backend, where every client hitting your website would need to be
able to access it.

Hope this helps,

Gavin

Aug 5, 2006, at 3:42 PM, Paul M Foster wrote:

I'm doing some massive (internal company) applications using PHP,
which query extensive PostgreSQL tables. This is fine, but
obviously it often requires multiple web pages to get something
done. Supposedly, AJAX promises to make web pages more interactive.
But from what I understand, I'd have to have bindings from
Javascript into PostgreSQL to make this work.

Here's an example: The user wants to enter a bill (accounts
payable) into the system. He first has to pick a vendor. Normally,
this would entail a PHP page that generates a PostgreSQL query. The
user would then get a second page with various vendor information
(like number of due days for that vendor), and various other
payable info. But wouldn't it be nice to have vendor information
filled in on the original page, directly after the user picks a
vendor? Theoretically, AJAX might allow something like this. But
from what I can see, it would require PostgreSQL bindings in
Javascript, and some way to pass the data back so that PHP could
use it.

Is this even possible? Is it being worked on? Is there a different
solution I don't know about? I can see where Javascript can alter
the look of a page, but I can't work out how it would allow
interactive use of a PostgreSQL table.

Paul M Foster wrote:
I'm doing some massive (internal company) applications using PHP, which
query extensive PostgreSQL tables. This is fine, but obviously it often
requires multiple web pages to get something done. Supposedly, AJAX
promises to make web pages more interactive. But from what I understand,
I'd have to have bindings from Javascript into PostgreSQL to make this
work.

Here's an example: The user wants to enter a bill (accounts payable)
into the system. He first has to pick a vendor. Normally, this would
entail a PHP page that generates a PostgreSQL query. The user would then
get a second page with various vendor information (like number of due
days for that vendor), and various other payable info. But wouldn't it
be nice to have vendor information filled in on the original page,
directly after the user picks a vendor? Theoretically, AJAX might allow
something like this. But from what I can see, it would require
PostgreSQL bindings in Javascript, and some way to pass the data back so
that PHP could use it.

Is this even possible? Is it being worked on? Is there a different
solution I don't know about? I can see where Javascript can alter the
look of a page, but I can't work out how it would allow interactive use
of a PostgreSQL table.

No - AJAX is really talking about the ability to use client-side JavaScript to
request XML documents from a server.

In this case if you want to have a page show vendor information when a user
selects a specific vendor, then your client-side JavaScript would request a
resource on your server that will return that information in XML.

If you're using PHP then the request you might make might be something like:

The PHP request on the server goes to Postgres and retrieves the appropriate
information, formats it as XML and writes it out like any other page.

The client-side Javascript gets the XML response, uses client-side DM to decode
the response and changes the page HTML to include the appropriate information
without having the page do a refresh.

this is often not much faster than getting a different page, and is
one of the fundamental problems with things like AJAX and SA - each remote
request is remote - it has to go over the internet and suffers not only the
processing time at the database but also the network latency.

But to answer your question - there is *not* coupling between JavaScript and
Postgres. The JavaScript runs on the client, Postgres on the server and PHP as
your intermediary.

Best regards
Pete

Aug 5, 2006, at 3:42 PM, Paul M Foster wrote:

But from what I can see, it would require PostgreSQL bindings in
Javascript, and some way to pass the data back so that PHP could
use it.

No, you should be able to this all within PHP with a AJAX library.
99% of my ajax experience has been with Rails and there is no need
to make javascript talk directly to PostgreSQL.

Robby

If you take a peek at the CVS version of phpPgAdmin, you will see the
"autocomplete" functionality for foreign keyed columns when doing
"insert row" or "edit row". You can easily get started with that by
using the pagila database and trying to insert some data into
film_category.

$ cvs -d:pserver:anonymous@
login

$ cvs -z3 -d:pserver:anonymous@
co -P webdb

Pagila:

Files of interest is "autocomplete.php", this was part of my Google SoC project.

Regards,
John

8/5/06, Paul M Foster <paulf (AT) quillandmouse (DOT) comwrote:
I'm doing some massive (internal company) applications using PHP, which
query extensive PostgreSQL tables. This is fine, but obviously it often
requires multiple web pages to get something done. Supposedly, AJAX
promises to make web pages more interactive. But from what I understand,
I'd have to have bindings from Javascript into PostgreSQL to make this work.

Here's an example: The user wants to enter a bill (accounts payable)
into the system. He first has to pick a vendor. Normally, this would
entail a PHP page that generates a PostgreSQL query. The user would then
get a second page with various vendor information (like number of due
days for that vendor), and various other payable info. But wouldn't it
be nice to have vendor information filled in on the original page,
directly after the user picks a vendor? Theoretically, AJAX might allow
something like this. But from what I can see, it would require
PostgreSQL bindings in Javascript, and some way to pass the data back so
that PHP could use it.

Is this even possible? Is it being worked on? Is there a different
solution I don't know about? I can see where Javascript can alter the
look of a page, but I can't work out how it would allow interactive use
of a PostgreSQL table.