I'm using db_query() to select data from a PostgreSQL database. Is there a way to incrementally extract data from a query result created from an AJAX-linked PHP file? Here's an example attempt that uses a simplified variable assignment:
PHP file:
<?php
if (isset($test_var)) {
echo $test_var;
}
else {
echo "undefined";
$test_var = "Variable has been set";
//$test_var = db_query("...");
}
Source (main page):
<input type="submit" name="submit" value="Submit" onclick='click_query()'/>
<div id="myDivD" style="display: none;"></div>
<script>
function click_query() {
if (window.XMLHttpRequest) {
// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp=new XMLHttpRequest();
}
else {
// code for IE6, IE5
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange=function() {
if (this.readyState==4 && this.status==200) {
document.getElementById("myDivD").innerHTML=this.responseText;
alert(this.responseText);
}
}
xmlhttp.open("GET","/sites/all/modules/afb/afb.php, true);
xmlhttp.send();
}
</script>
I was optimistic this might work, but not terribly surprised that it failed. Only "undefined" was returned.
I've previously attempted doing everything client side (with PHP/Javascript) which resulted in slow load times. My dataset has since increased substantially (nearly x100). I'm trying to perform more processing server-side with AJAX. Ideally, I'd be able to run a custom SQL query, dictated by a user, a single time and pull select rows from the query result to populate a page. However, I haven't been able to figure out a way to keep the SQL query results saved in memory without passing everything to the client's side. This would make re-running the query necessary, which would produce impractical load times.
The queries are complex enough that saving specific query results server-side isn't realistic. Unless perhaps data could be compressed and incrementally decompressed client side to save memory and maximize performance? Is there a way to keep the PHP file linked via AJAX until the main page is refreshed or changed (to prevent losing assigned variables)? Although I don't have much experience in jQuery, I am also interested in possible jQuery solutions (which seems to be the preferred method for implementing AJAX).
