How can one trigger an event locally when a field in a connected database changes? I've done some research but it seems like there there are varying and inconclusive answers to the question.
I'm building an application where users rate comments, and I'd like to have the ratings change live when they are modified by a different user. For example: users A and B are both viewing the comment feed. Say user A uprates a comment, causing the "rating" field for that comment's row in my database table to be incremented. Without having a timer for periodic refreshing, I'd like to have user B see the change in comment (updated on his page) as soon as A has rated it. Is there a way to do this using just PHP, SQL, and JavaScript/jQuery, or applicable plugins/libraries?
Examples, ideas, links, etc. all appreciated. Thanks so much for the help.
The technique is called Comet, a play on words to Ajax. There are many ways to accomplish it. See here: http://en.wikipedia.org/wiki/Comet_(programming)
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I'm developing an Online Judge as part of my university project. Done setting up the compiler. But the problem is I want to insert all the user inputs in one queue and compile and execute them one by one. This question may seem funny too you but as a noob I don't even know what to write in google search engine. Tried many ways to search in google. Elaborative ways as I should say. Even facebook groups were no help at all.
I repeat my problem again, suppose there are 100 users submitting 100 codes at the same time. I need to put all of them in a single queue then process them one by one.
If you just tell me the name of this procedure that'll be very much helpful. I'll study the rest.
thank you. please don't get offended for such silly question.
regards!
Create a database (mysql or whatsoever) and a table that meets the data you need to store.
For each form submit, store the data in the table.
Run a cronjob task and fetch rows from the database. Mark these rows as "processing" just once you fetch them and "completed" once you process them.
Voila!
I want to add functionality to a website I am building for a client that allows him to log on to a secure page and add new job listings. He will be the only one modifying this so I don't need to worry about concurrent access or anything like that. At this point I don't even have a database set up for him but I understand that might need to be implemented soon, for other features if not this one.
He doesn't have any knowledge of HTML so I can't just create a template job posting and have him manually fill in the information (although that is also unprofessional, I suppose.) I was planning on just making a simple php/html page where he could put the title of the job along with all details through submission of a form. Once I have that, though, I don't know how to deal with adding that job title to a list of current job postings and also have that link to a new page with all the details of the job.
My memory from early undergraduate classes are hinting that the adding jobs to a list would be object-oriented. However, I can also see something where I would just add the title to an array which the list then dynamically filled from.
Another recommendation I have received is to look into implementing a django/python solution. The problem is I have about a week to work on this and I ahve no python experience. If that is something that would be possible to learn and implement in that time, I will go for it. I just don't want to waste time on something that takes a week or two to learn and then still have nothing implemented.
Basically, I would appreciate a point in the right direction and some reassurance that I am considering all possibilities. If it would be easier to implement some kind of simple wiki, that is another option as well.
Do any of these ideas sound like the right choice? Is there anything I am missing?
I apologize if this is a trivial question but I have stumped myself and would appreciate any help you can offer.
A possible and easy solution would be using an appropriate CMS module, like Job Manager or Resume Submissions and Job Posting for WordPress. I haven't tested them personally, but they should handle everything for you through a Web interface, no coding needed (you should just adapt the WordPress CSS to match the existing client's Website style).
For reference, here's what I would have done in case no such CMS module existed.
Create a database with a table that will hold all job postings. The table should have the following columns: id, title, description, validityDate (names are self-explanatory). Add more if appropriate.
Write a script that queries the database for all current job postings using the following query: SELECT id, title FROM postings WHERE validityDate >= NOW(). To manage database connections, use the PHP PDO extension (look at its page on the PHP manual website for examples). This will return a list of all current job postings. For each result, let the script output HTML code like this: echo "$title<br />$description";, where $id, $title and $description are the variables holding the ID, title and description of the current record.
Write the post.php script that will fetch the details of the job posting with the ID specified in the id parameter.
Write another script where the client will input the details for a new posting into a form. After submission, the script should just insert the data into the table.
Ok. I didn't know how to put this question in Title so here is a quick description.
Let's say I have site with some promotional stuff to give for free (or not:).
When I have something to give I announce this on facebook and twitter etc. and people can come to website and fill quick form, couple quick questions and of course name and address.
But the problem is I have for example 20 pieces of this thing to give for free.
When you submit the form this goes automatically to database table.
I know how to display current status for this offer with some PHP (like: there's only 12 items left.hurry up!), there is also no problem with refreshing this every couple seconds with AJAX. But problem I see in here is when let's say this will become more popular and I will have many offers during short time.
I don't want database to be overloaded with queries from hundreds of people every two seconds.
Is there any way to send just one query every two seconds (somewhere on the sever?) and just somehow update value from this query in any browser currently visiting the website?
I'm not sure if this is clear question but what I'm asking is what would be the best practice for this kind of situation.
Is my concern about overloading the database even reasonable?
And extra problem...
In this particular situation - with the limit for amount of people that can participate - is there any threat that I can have strange behavior when two people will send form in exactly the same time when there is only one item left?
I would love to see any directions in this subject. Even general one will do :)
PS: No, english is not my first language :)
Thx
Can't you have one script loading from the database and save it somewhere that isn't the database (a file, preferably) and then it can be extracted from there? This will include a cronjob for that script to be run every 5 second.
For reference, here is a question on SO that I asked recently that is relevant to this question: How to model Friendship relationships
On that question, we figured out a way to display news feed items only if posted by friends. However, what I need is advice on how to check for friendship in a more dynamic way so it can be used throughout several site functions.
For example, I've just installed a comment system, allowing users to post comments on news posts. However, this isn't restricted to friends, and it should be (and later should be made optional by the author of the post).
Posting news items only by friends was slightly different because I was getting data directly from the database, and using SELECT subqueries to only get posts by friends of the current user. However, in the example of the commenting, I only want to display the comment post form if the person is a friend. I'm not actually pulling anything from the database to pick, sort, and display.
Knowing issues like this will arise many times throughout the site, what would be the simplest way to check for friendship? Could I somehow pull all the friends' user IDs from the database into a session array of some kind and then do an if(in_array($friends)) whenever I needed to determine if the person in question is a friend of the currently logged in user? Off the top of my head, this sounds like it would work fine, but I'd like your input first.
The question I linked to above explains how my friendship table works, in case that help you help me with this.
Actually, it is a very bad idea to stor the friend array in the session. What happens if some you add a new friend after the session variable is created? It does not get updated in the session.
Since you will be checking the list of friends a lot of times on the same page, why not just query it out and store it in a local array that you can keep using on the same page.
When the page finish executing, the array will be discarded.
So basically, you will only query the list out once.
A recommended implementation would be to follow the advise of "pst" in the above comment, and just query for every time you need to find the relationship first, as that is simple to implement. Later, when the speed of the query starts to become a issue, you can just change the internal of that method to cache the friend list in a local array when it is first called to speed things up. (exchange memory usage for processor usage).
Using PHP5 and the latest version of MySQL I want to be able to track impressions and clicks for business listings. My question is if I did this myself what would be the best method in storing it so I can run reports? Before I just had a table that had the listing id, user ip address and if it was a click or impression as well as the date it was tracked. However the database itself is approaching 2GB of data and its very slow, part of the problem is its a pretty simple script that includes impressions and clicks from anyone including search engines and basically anyone or anything that accesses the listing page.
Is there an api or file out there that has an update to date list that can detect if the person viewing is a actually person and not a spider so I dont fill up the database with unneeded stats? Just looking for suggestions, do I just have a raw database that gets just the hits then a cron job at night tally up for the day for each listing for each ip and store the cumulative stats in a different table?
Also what type of database should it be? Innodb? MyISAM?
I would think that you will never create something better then what is already out there. I'd use Google's analytics. If you want to use it in an admin side of a site (for a client to run may-be) you can always use googles api and pull the data as you need. here is where I'd look.. http://code.google.com/intl/en-US/apis/analytics/
hth Cheers -Jeremy
Just in case you need to distinguish real users from bots, here's a simple solution: use javascript for sending reports to the server.
Let's say you have a link and you want to track when it's clicked. Then add an onclick handler, which will send a decent report to the server. Here's an example:
Some page
The track function would look like this one:
function track(action, data) {
var Img = new Image();
Img.src = '/track.php?action=' + action + '&data=' + data;
}
So in this case when a user clicks the link, the information about this click will be sent to the server by this piece of javascript code. Bots can't run javascript, so they won't be counted. There is one drawback though, if a user has disabled javascript in his browser, your tracking script won't count such a user. Obviously, you'll need to implement the track.php script in order to store the data.
Concerning your MySQL question, I'd pick MyIsam as it seems to be more tolerant to lots of intserts. Also, you can look at INSERT DELAYED statement, and your idea about nightly cron jobs seems reasonable to me. You can split your statistics table by days, weeks, or months as well.
99.999% of the time, you will juste write into the database.
So for this kind of work, daily partitioned MySQL tables will do the job.
Each day write on the same partition, and run an ANALYZE PARTITION on your yesterday partition.