I'm trying to draw a real time graph as my mysql table is constantly being inserted with values, like a moving graph referenced from
http://kalanir.blogspot.com/2009/11/how-to-plot-moving-graphs-using-flot.html
The values actually come from a carbon dioxide sensor which updates the value of the table with co2 values with positions id. I changed her Math.Random to the code below:
<?php $result = mysql_query("SELECT * FROM node1 ORDER BY id DESC LIMIT 1")or die(mysql_error());?>
<?php $row = mysql_fetch_array( $result );?>
var j = "<?php echo $row['co2'];?>";
var next = "<?php echo $row['id'];?>";
for (var i = 0; i < this.xscale - 1; i++)
{
this.array[i] = [i,this.array[i+1][1]]; // (x,y)
}
this.array[this.xscale - 1] = [this.xscale - 1,j];
However, when i run this code, the first value changes, after which it remains constant, even though the last row of the table is being updated.
I heard it is because in php, the server is only polled once. Therefore i only get a constant reading of the first data. Is there any way in which i can make the graph update to the last value of the table? with ajax?
Thanks for your help
Yes, you can use Periodic refresh (Polling)
or
HTTP Streaming.
Note that both of these options can be quite bandwidth demanding.
you have to do some sort of polling. But even before you do that,
1. create a php file that retrieves all the important data from the db.
2. let that file echo/return that data in a formatted way.
3. have js function poll that file at intervals (a function that runs in setInterval() )
and yes.. there would be some bandwith issues but i think its manageable.
Related
I am attempting to create a progress bar from numeric values within a database. I have two fields within the database, one is called 'NEXT_STEP' and the other is called 'MAX_STEPS' - When NEXT_STEP = MAX_STEPS + 1, then all the steps have been completed and the progress bar should be full (100%). These steps will happen in real time, and the NEXT_STEP will increment as a process in the background progresses. The web page displaying the progress will hopefully update along with it, so use of AJAX will be required.
To do this, I am trying to retrieve these numeric values from the database, store them to PHP variables, so I can then calculate the percentage and display a progress bar with an accurate percentage. Then, making use of AJAX and a time interval, I can call the method repeatedly to update the progress bars.
So, my questions are:
How can I retrieve a field from a database and store it to a PHP variable?
How would I go about retrieving multiple rows of data, and then selecting the relevant fields and calculating the percentage? (I assume a while loop, but not entirely certain)
I have tried to make use of oci_define_by_name() to store the fields to PHP variables.
Also, I have tried to use oci_fetch() alongside oci_result() to retrieve the relevant data from the array that is fetched when the DB is queried but to no prevail.
$sql='select * from lookout_status order by TIMESTAMP_1 DESC';
$stid= oci_parse($conn, $sql);
echo $sql;
oci_define_by_name($stid, 'NEXT_STEP', $next);
echo $next;
oci_execute($stid);
I don't get an output where I expect a value to be echoed, so I'm quite lost.
Thanks for any help provided in advance.
EDIT:
I managed to solve it - For future reference if anyone comes across this question, use oci_define_by_name() to define the values from the DB to PHP variables. Then, execute the sql query, and make use of oci_fetch() inside a while loop to retrieve the values for each row of data. You can then do whatever you need to do with the data.
Thanks for the help received.
Use oci_define_by_name() to define the values from the DB to PHP variables. Then, execute the sql query, and make use of oci_fetch() inside a while loop to retrieve the values for each row of data. You can then do whatever you need to do with the data.
$stid= oci_parse($conn, $sql);
echo $sql;
echo "<br>";
oci_define_by_name($stid, 'NEXT_STEP', $next);
oci_define_by_name($stid, 'MAX_STEPS', $max);
oci_execute($stid);
while (oci_fetch($stid)){
//Some code omitted here...
$val = round($percent, 0);
echo $val;
$prog = "<progress value='$val' max='100'></progress>";
echo $prog;
echo "<br>";
echo "<br>";
}
You use PDO class to get result set from database. And then get loop over fetched result and calculate which you want.
I need to come up with a way to make a large task faster to beat the timeout.
I have very limited access to the server due to the restrictions of the hosting company.
I have a system set up where a cron visits a PHP file that grabs a csv that contains data on some products. The csv does not contain all of the fields that the product would have. Just a handful of essential ones.
I've read a fair number of articles on timeouts and handling csv's and currently (in an attempt to shave time) I have made a table (let's call it csv_data) to hold the csv data. I have a script that truncates the csv_data table then inserts data from the csv so each night the latest recordset from the csv is in that table (the csv file gets updated nightly). So far, no timeout problems..the task only takes about 4-5 seconds.
The timeouts occur when I have to sift through the data to make updates to the products table. The steps that it is running right now is like this
1. Get the sku from csv_data table (that holds thousands of records)
2. Select * from Products where products.sku = csv.sku (products table also holds thousands of records to loop through)
3. Get numrows.
If numrows<0{no record in products, so skip}.
If numrows>1{duplicate entries, don't change anything, but later on report the sku}
If numrows==1{Update selected fields in the products table with csv data}
4. Go to the next record in csv_data all over again
(I figured outlining the process is shorter and easier than dropping in the code.)
I looked into MySQl views and stored procedures but I am not skilled enough in it to know if it will handle the 'if' statement portion.
Is there anything I can do to make this faster to avoid the timeouts?
edit:
I should mention that set_time_limit(0); isn't doing it. And if it helps, the server uses IIS7 and fastcgi
Thanks for your help.
Update after using suggestions from Jakob and Shawn:
I'm doing something wrong. The speed is definitely faster and the csv sku is incrementing,
but when I tried to implement Shawn's solution; the query is giving me a PHP Warning: mysql_result() expects parameter 1 to be resource, boolean error.
Can you help me spot what I am doing wrong?
Here is the section of code:
$csvdata="SELECT * FROM csv_update";
$csvdata_result=mysql_query($csvdata);
mysql_query($csvdata);
$csvdata_num = mysql_num_rows($csvdata_result);
$i=0;
while($i<$csvdata_num){
$csv_code=#mysql_result($csvdata_result,$i,"skucode");
$datacheck=NULL;
$datacheck=substr($csv_code,0,1);
if($datacheck>='0' && $datacheck<='9'){
$csv_price=#mysql_result($csvdata_result,$i,"price");
$csv_retail=#mysql_result($csvdata_result,$i,"retail");
$csv_stock=#mysql_result($csvdata_result,$i,"stock");
$csv_weight=#mysql_result($csvdata_result,$i,"weight");
$csv_manufacturer=#mysql_result($csvdata_result,$i,"manufacturer");
$csv_misc1=#mysql_result($csvdata_result,$i,"misc1");
$csv_misc2=#mysql_result($csvdata_result,$i,"misc2");
$csv_selectlist=#mysql_result($csvdata_result,$i,"selectlist");
$csv_level5=#mysql_result($csvdata_result,$i,"level5");
$csv_frontpage=#mysql_result($csvdata_result,$i,"frontpage");
$csv_level3=#mysql_result($csvdata_result,$i,"level3");
$csv_minquantity=#mysql_result($csvdata_result,$i,"minquantity");
$csv_quantity1=#mysql_result($csvdata_result,$i,"quantity1");
$csv_discount1=#mysql_result($csvdata_result,$i,"discount1");
$csv_quantity2=#mysql_result($csvdata_result,$i,"quantity2");
$csv_discount2=#mysql_result($csvdata_result,$i,"discount2");
$csv_quantity3=#mysql_result($csvdata_result,$i,"quantity3");
$csv_discount3=#mysql_result($csvdata_result,$i,"discount3");
$count_check="SELECT COUNT(*) AS totalCount FROM products WHERE skucode = '$csv_code'";
$count_result=mysql_query($count_check);
mysql_query($count_check);
$totalCount=#mysql_result($count_result,0,'totalCount');
$loopCount = ceil($totalCount / 25);
for($j = 0; $j < $loopCount; $j++){
$prod_check="SELECT skucode FROM products WHERE skucode = '$csv_code' LIMIT ($loopCount*25), 25;";
$prodresult=mysql_query($prod_check);
mysql_query($prod_check);
$prodnum =#mysql_num_rows($prodresult);
$prod_id=#mysql_result($prodresult,0,"catalogid");
if($prodnum<1){
echo "NOT FOUND:$csv_code<br>";
$count_sku_not_found=$count_sku_not_found+1;
$list_sku_not_found=$list_sku_not_found." $csv_code";}
if($prodnum>1){
echo "DUPLICATE:$csv_ccode<br>";
$count_duplicate_skus=$count_duplicate_skus+1;
$list_duplicate_skus=$list_duplicate_skus." $csv_code";}
if ($prodnum==1){
///This prevents an overwrite from happening if the csv file doesn't produce properly
if ($csv_price!="" OR $csv_price!=NULL)
{$sql_price='price="'.$csv_price.'"';}
if ($csv_retail!="" OR $csv_retail!=NULL)
{$sql_retail=',retail="'.$csv_retail.'"';}
if ($csv_stock!="" OR $csv_stock!=NULL)
{$sql_stock=',stock="'.$csv_stock.'"';}
if ($csv_weight!="" OR $csv_weight!=NULL)
{$sql_weight=',weight="'.$csv_weight.'"';}
if ($csv_manufacturer!="" OR $csv_manufacturer!=NULL)
{$sql_manufacturer=',manufacturer="'.$csv_manufacturer.'"';}
if ($csv_misc1!="" OR $csv_misc1!=NULL)
{$sql_misc1=',misc1="'.$csv_misc1.'"';}
if ($csv_misc2!="" OR $csv_misc2!=NULL)
{$sql_pother2=',pother2="'.$csv_misc2.'"';}
if ($csv_selectlist!="" OR $csv_selectlist!=NULL)
{$sql_selectlist=',selectlist="'.$csv_selectlist.'"';}
if ($csv_level5!="" OR $csv_level5!=NULL)
{$sql_level5=',level5="'.$csv_level5.'"';}
if ($csv_frontpage!="" OR $csv_frontpage!=NULL)
{$sql_frontpage=',frontpage="'.$csv_frontpage.'"';}
$import="UPDATE products SET $sql_price $sql_retail $sql_stock $sql_weight $sql_manufacturer $sql_misc1 $sql_misc2 $sql_selectlist $sql_level5 $sql_frontpage $sql_in_stock WHERE skucode='$csv_code'";
mysql_query($import) or die(mysql_error("error updating in products table"));
echo "Update ".$csv_code." successful ($i)<br>";
$count_success_update_skus=$count_success_update_skus+1;
$list_success_update_skus=$list_success_update_skus." $csv_code";
//empty out variables
$sql_price='';
$sql_retail='';
$sql_stock='';
$sql_weight='';
$sql_manufacturer='';
$sql_misc1='';
$sql_misc2='';
$sql_selectlist='';
$sql_level5='';
$sql_frontpage='';
$sql_in_stock='';
$prodnum=0;
}
}
$i++;
}
Is it timing out before the first row is returned or is it between rows during the read? One good practice bit would be to handle your query in chunks; do a count first to see how many records you are dealing with for the SKU, the loop through smaller chunks (the size of these chunks would depend on how many things you have to do with each row). Your updated workflow would look more like this:
Get next SKU from CSV
Get a total count: SELECT COUNT(*) AS totalCount FROM products WHERE products.sku = csv.sku
Determine chunk size (using 25 for this demo)
loopCount = ceil(totalCount / 25)
Loop through all results using a loop like this: for($i = 0; $i < loopCount; $i++)
Inside your loop you should be running a query like this: SELECT * FROM products WHERE products.sku = csv.sku LIMIT (loopCount*25), 25
You will want to use a constant order for your SELECT chunks; your unique ID would probably be best.
I think you can solve this problem with cron. http://en.wikipedia.org/wiki/Cron . It has never had timeout.
Is it possible to keep checking a MySQL database and then update text? I'm using this to get the number of rows and then it's echo-ed:
$result = mysql_query("SELECT * FROM socialacc WHERE transid='$transID' AND access='$access'");
$i = 0;
while($row = mysql_fetch_array($result)) {
$i = $i + 1;
}
echo $i;
I want this code to be repeated so that if there's ever another row that matches, the text would be updated without the page being reloaded. Would I use Javascript to repeat the check? Any idea's how I would go about it? Thanks for the help.
First of all, you can let the database count for you:
$result = mysql_query("SELECT COUNT(*) FROM socialacc WHERE transid='$transID' AND access='$access'");
$result = mysql_fetch_array($result);
echo $result[0];
Then, you'll probably want to repeat this query every so often through an AJAX call, but not so often that it'll kill your database.
You have two choices here: server push or AJAX.
Server push is probably simpler to program at the client side but quite complicated to write the server side in a way that won't eat some system resource or other on your server. AJAX more complicated at the client side, but simpler and easier to implement overall.
I would recommend the AJAX route for this job.
I have a mysql query that retrieves all my topic results. I then have a pagination system where results are separated into pages and the query's limit #,# changes based on what page you are on.
What I want to do is put all those results into two separate div containers. I want 21 results on each page. The first 9 I will put in one div. The next 12 will go in the other. Does anyone know an efficient way to do this? Should I use two queries, or javascript, or another way? I am just looking for the best most efficient way to do this. Unfortunately the pagination system makes two queries difficult. Any suggestions highly appreciated.
$sql = "SELECT * FROM topics LIMIT ?,?";
$stmt2 = $conn->prepare($sql);
$result=$stmt2->execute(array(somenumber,somenumber2));
I don't see any reason why you can't do a single MySQL query and use JavaScript to sort the results. Understand that I don't understand here what your data is coming back looking like, so any example I provide will have to remain pretty agnostic in this regard.
I will, however, assert as an assumption that you have a JavaScript array of length 21 with some data that is the basis for your display.
Assuming that we're just talking about the first 9, and the last 12, the sorting code is as simple as:
// assume my_array is the array mentioned above
for (var i = 0; i < 9; i += 1) {
var html = code_to_transform_data_from_array(array[i]);
$('.div1').append($(html));
}
for (var i = 9; i < 21; i += 1) {
var html = code_to_transform_data_from_array_b(array[i]);
$('.div2').append($(html));
}
If your sorting condition is any more complicated, then you'd be better off with something like...
while (my_array.length > 0) {
var item = my_array.pop();
if (sorting_condition) {
$('.div1').append(f1(item));
}
else {
$('.div2').append(f2(item));
}
}
(In the second example, I became a lazy typist and assumed f1 and f2 to be complete transformation functions. sorting_condition is your criteria for determining in which bucket something goes.
Hope that sets you off on the right track.
I have a table in database that has 2 columns Name | Age, I display it in a HTML page.
I want to sort the table in HTML page based on a field when the user clicks on it.
I have a PHP function to do the sorting based on a field.
But after obtaining the rows in sorted order in PHP, I'm looking for ways by which I can update the HTML table without navigating away from the page.
You do not need to communicate between the client and server to do this, just sort the table on the client directly.
There is a jQuery plug-in for this that works quite well:
http://tablesorter.com/docs/
You can do sorting in javascript, without having to communicate with the server. For example, this code will sort a table based on the content of the Nth column:
function sortTable(table, column, skipHeader) {
// Stick each row into an array.
var rows = [];
for (var i = skipHeader ? 1 : 0; i < table.rows.length; i++) {
rows.push(table.rows[i]);
}
// Sort the array based on the innerText of the column'th cell in each row
rows.sort(function(a, b){
a = a.cells[column].innerText;
b = b.cells[column].innerText;
return a < b ? -1 : (b < a ? 1 : 0);
});
// Re-order the rows by removing/appending in the sort order
for (var i = 0; i < rows.length; i++) {
var row = rows[i];
var container = row.parentElement;
container.removeChild(row);
container.appendChild(row);
}
}
For example, to sort the first table in the document, on the first column, and skip the header row:
sortTable(document.getElementsByTagName('table')[0], 0, true);
Obviously you'll want to modify this to suit your own tastes, especially the sorting, but it's a lot simpler than having to post the data back to the server, which I think is what you're proposing.
Since others have covered the fact that client-side sorting would work just fine here, I'll just point you to the resource with which I've had the most sucess doing this kind of thing: Google Data Tables, part of their Visualization Library. Here are the deets on what you can do (spoiler: everything you want and more).
Here is a link to a javascript library to make your tables sortable using javascript instead of php. I've used it many times, it works great.
Javascript Sortable Tables by: Stuart Langridge