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  • Persistent (purely functional) Red-Black trees on disk performance

    - by Waneck
    I'm studying the best data structures to implement a simple open-source object temporal database, and currently I'm very fond of using Persistent Red-Black trees to do it. My main reasons for using persistent data structures is first of all to minimize the use of locks, so the database can be as parallel as possible. Also it will be easier to implement ACID transactions and even being able to abstract the database to work in parallel on a cluster of some kind. The great thing of this approach is that it makes possible implementing temporal databases almost for free. And this is something quite nice to have, specially for web and for data analysis (e.g. trends). All of this is very cool, but I'm a little suspicious about the overall performance of using a persistent data structure on disk. Even though there are some very fast disks available today, and all writes can be done asynchronously, so a response is always immediate, I don't want to build all application under a false premise, only to realize it isn't really a good way to do it. Here's my line of thought: - Since all writes are done asynchronously, and using a persistent data structure will enable not to invalidate the previous - and currently valid - structure, the write time isn't really a bottleneck. - There are some literature on structures like this that are exactly for disk usage. But it seems to me that these techniques will add more read overhead to achieve faster writes. But I think that exactly the opposite is preferable. Also many of these techniques really do end up with a multi-versioned trees, but they aren't strictly immutable, which is something very crucial to justify the persistent overhead. - I know there still will have to be some kind of locking when appending values to the database, and I also know there should be a good garbage collecting logic if not all versions are to be maintained (otherwise the file size will surely rise dramatically). Also a delta compression system could be thought about. - Of all search trees structures, I really think Red-Blacks are the most close to what I need, since they offer the least number of rotations. But there are some possible pitfalls along the way: - Asynchronous writes -could- affect applications that need the data in real time. But I don't think that is the case with web applications, most of the time. Also when real-time data is needed, another solutions could be devised, like a check-in/check-out system of specific data that will need to be worked on a more real-time manner. - Also they could lead to some commit conflicts, though I fail to think of a good example of when it could happen. Also commit conflicts can occur in normal RDBMS, if two threads are working with the same data, right? - The overhead of having an immutable interface like this will grow exponentially and everything is doomed to fail soon, so this all is a bad idea. Any thoughts? Thanks! edit: There seems to be a misunderstanding of what a persistent data structure is: http://en.wikipedia.org/wiki/Persistent_data_structure

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  • NHibernate GenericADO Exception

    - by Ris90
    Hi, I'm trying to make simple many-to-one association, using NHibernate.. I have class Recruit with this mapping: <class name="Recruit" table="Recruits"> <id name="ID"> <generator class="native"/> </id> <property name="Lastname" column="lastname"/> <property name="Name" column="name"/> <property name="MedicalReport" column="medicalReport"/> <property name="DateOfBirth" column ="dateOfBirth" type="Date"/> <many-to-one name="AssignedOnRecruitmentOffice" column="assignedOnRecruitmentOffice" class="RecruitmentOffice"/> which is many-to-one connected to RecruitmentOffices: <class name="RecruitmentOffice" table="RecruitmentOffices"> <id name="ID" column="ID"> <generator class="native"/> </id> <property name="Chief" column="chief"/> <property name="Name" column="name"/> <property name ="Address" column="address"/> <set name="Recruits" cascade="save-update" inverse="true" lazy="true"> <key> <column name="AssignedOnRecruitmentOffice"/> </key> <one-to-many class="Recruit"/> </set> And create Repository class with method Insert: public void Insert(Recruit recruit) { using (ITransaction transaction = session.BeginTransaction()) { session.Save(recruit); transaction.Commit(); } } then I try to save new recrui to base: Recruit test = new Recruit(); RecruitmentOffice office = new RecruitmentOffice(); ofice.Name = "test"; office.Chief = "test"; test.AssignedOnRecruitmentOffice = office; test.Name = "test"; test.DateOfBirth = DateTime.Now; RecruitRepository testing = new RecruitRepository(); testing.Insert(test); And have this error GenericADOException could not insert: [OSiUBD.Models.DAO.Recruit][SQL: INSERT INTO Recruits (lastname, name, medicalReport, dateOfBirth, assignedOnRecruitmentOffice) VALUES (?, ?, ?, ?, ?); select SCOPE_IDENTITY()] on session.Save

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  • Error Handling for Application in PHP

    - by Zubair1
    I was wondering if someone can show me a good way to handle errors in my PHP app, that i am also easily able to reuse in my codes. So far i have been using the following functions: Inline Errors function display_errors_for($fieldname) { global $errors; if (isset($errors[$fieldname])) { return '<label for="' .$fieldname. '" class="error">' . ucfirst($errors[$fieldname]). '</label>'; } else { return false; } } All Errrors function display_all_errors($showCounter = true) { global $errors; $counter = 0; foreach ($errors as $errorFieldName => $errorText) { if ($showCounter == true) { $counter++; echo '<li>' . $counter . ' - <label for="' .$errorFieldName. '">' .$errorText. '</label></li>'; } else { echo '<li><label for="' .$errorFieldName. '">' .$errorText. '</label></li>'; } } } I have a $errors = array(); defined on the top of my global file, so it is appended to all files. The way i use it is that if i encounter an error, i push a new error key/value to the $errors array holder, something like the following: if (strlen($username) < 3) { $errors['username'] = "usernames cannot be less then 3 characters."; } This all works great and all, But i wondering if some one has a better approach for this? with classes? i don't think i want to use Exceptions with try/catch seems like an overkill to me. I'm planning to make a new app, and i'll be getting my hands wet with OOP alot, though i have already made apps using OOP but this time i'm planning to go even deeper and use OOP approach more extensively. What i have in mind is something like this, though its just a basic class i will add further detail to it as i go deeper and deeper in my app to see what it needs. class Errors { public $errors = array(); public function __construct() { // Initialize Default Values // Initialize Methods } public function __destruct() { //nothing here too... } public function add($errorField, $errorDesc) { if (!is_string($errorField)) return false; if (!is_string($errorDesc)) return false; $this->errors[$errorField] = $errorDesc; } public function display($errorsArray) { // code to iterate through the array and display all errors. } } Please share your thoughts, if this is a good way to make a reusable class to store and display errors for an entire app, or is getting more familiar with exceptions and try/catch my only choice?

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  • How to use the Value of a Selected Value from a DropDownList populated with AJAX/PHP

    - by mouthpiec
    Hi, I have form with two dropdownlists (lets say A and B). When I select a value from A, B is being populated accordingly using AJAX In the same page I have a button, that when pressed, posts the values of the selected items of the dropdownlists to another PHP page. The problem I am having is that the selected value of B is returned as Blank/Empty. Is there a way to store the selected value of a dropdownlist populated using AJAX? Code below: (Main FORM) <form name="NewBar" method="post" onsubmit="return validateFormOnSubmit(this)" action="AssignContactDetailToBar_f.php"> <tr> <td width="150"><b>Bar:</b></td> <td> <select name = "bar" onChange="getContact('AssignContactDetailToBar_f_getContacts.php?bar='+this.value)" size = 1 style = "width:190px"> <option value = "">---Select---</option> <?php while ($data = mysql_fetch_array($r_getBarsDetails)) { echo "<option value=\"".$data['bar_id']."\">".$data['bar_name']." (".$data['town_name'].")</option>"; } ?> </td> </tr> <tr> <td width="150"><b>Contact Person:</b></td> <td> <div id="persondiv"><select name = "person" size = 1 style = "width:190px"> <option value = "">--Select Bar--</option> </td> </tr> <tr> <td> <input name="security" type="text" size="15"> </td> <td> <input type="submit" name="Submit" value="Submit"> </td> </tr> </form> FORM to populate the 2nd Dropdownlist <select name="person" size = 1 style = "width:190px"> <option value = "">--Select Person--</option> <?php while($data=mysql_fetch_array($result)) { echo "<option value=\"".$data['person_id']."\">".$data['person_name']." ".$data['person_surname']." (".$data['town_name'].")</option>"; } ?> if you would like to see the complete code download from here

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  • Unable to install gem "pg" on Ubuntu 12.10 (AMD64)

    - by Lynx_Eyes
    I've been (unsuccessfully) trying to install the "pg" gem on my ruby 1.9.3-p286 but nothing seems to work. I've already installed postgresql (9.1), libpq-dev and a few others like postgresql-server-dev-9.1. I've tried to pass the "with-pg-config" flag to the gem install but simply nothing seems to work. Every time I try to install the gem it outputs something like this: Building native extensions. This could take a while... ERROR: Error installing pg: ERROR: Failed to build gem native extension. /home/lynux/.rvm/rubies/ruby-1.9.3-p286/bin/ruby extconf.rb checking for pg_config... yes Using config values from /usr/bin/pg_config checking for libpq-fe.h... yes checking for libpq/libpq-fs.h... yes checking for pg_config_manual.h... yes checking for PQconnectdb() in -lpq... no checking for PQconnectdb() in -llibpq... no checking for PQconnectdb() in -lms/libpq... no Can't find the PostgreSQL client library (libpq) *** extconf.rb failed *** Could not create Makefile due to some reason, probably lack of necessary libraries and/or headers. Check the mkmf.log file for more details. You may need configuration options. Provided configuration options: --with-opt-dir --with-opt-include --without-opt-include=${opt-dir}/include --with-opt-lib --without-opt-lib=${opt-dir}/lib --with-make-prog --without-make-prog --srcdir=. --curdir --ruby=/home/lynux/.rvm/rubies/ruby-1.9.3-p286/bin/ruby --with-pg --without-pg --with-pg-dir --without-pg-dir --with-pg-include --without-pg-include=${pg-dir}/include --with-pg-lib --without-pg-lib=${pg-dir}/lib --with-pg-config --without-pg-config --with-pg_config --without-pg_config --with-pqlib --without-pqlib --with-libpqlib --without-libpqlib --with-ms/libpqlib --without-ms/libpqlib Gem files will remain installed in /home/lynux/.rvm/gems/ruby-1.9.3-p286@phisiodata/gems/pg-0.14.1 for inspection. Results logged to /home/lynux/.rvm/gems/ruby-1.9.3-p286@phisiodata/gems/pg-0.14.1/ext/gem_make.out What am I doing wrong? Is there something else that I should do before trying to install the gem? Thank you in advance. [EDIT] Ok, so joelparkerhenderson's answer set me to think that there might me something wrong with paths and libraries and a went on digging a little bit further.. I've found this awesome post and it solved! Basically the problem lies with RVM. So, my problem is solved and for anyone out there that might suffer from the same thing, follow the link!

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  • current location too slow for view

    - by Christian
    Hi, I make an App with a Map in the App and a button to change to the google.Map-App. The code for my position is: -(void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation { float avgAccuracy = (newLocation.verticalAccuracy + newLocation.horizontalAccuracy)/2.0; if (avgAccuracy < 500) { [locationManager stopUpdatingLocation]; locationManager.delegate = nil; } storedLocation = [newLocation coordinate]; The code for the view is: - (void)viewDidLoad { [super viewDidLoad]; UIImage *image = [UIImage imageNamed: @"LogoNavBar.png"]; UIImageView *imageview = [[UIImageView alloc] initWithImage: image]; UIBarButtonItem *button = [[UIBarButtonItem alloc] initWithCustomView: imageview]; self.navigationItem.rightBarButtonItem = button; [imageview release]; [button release]; locationManager=[[CLLocationManager alloc] init]; locationManager.delegate = self; locationManager.desiredAccuracy = kCLLocationAccuracyBest; locationManager.distanceFilter = kCLDistanceFilterNone; [locationManager startUpdatingLocation]; mapView.showsUserLocation = YES; NSLog(@"storedLocation-latitude für MKregion: %f", storedLocation.latitude); MKCoordinateRegion region; region.center.latitude = (storedLocation.latitude + 45.58058)/2.0; region.center.longitude = (storedLocation.longitude - 0.546835)/2.0; region.span.latitudeDelta = ABS(storedLocation.latitude - 45.58058); region.span.longitudeDelta = ABS(storedLocation.longitude + 0.546835); [mapView setRegion:region animated:TRUE]; MKCoordinateRegion hotel; hotel.center.latitude = 45.58058; hotel.center.longitude = -0.546835; HotelPositionMarker* marker = [[HotelPositionMarker alloc] initWithCoordinate:hotel.center]; [mapView addAnnotation:marker]; [marker release]; } My problem: when the "viewDidLoad" start, the "storedLocation" is still 0.0000 it takes a bit longer to get the own position than to start the view. The Log for the "storedLocation" in the "viewDidLoad"-section is 0 while the Log of the "storedLocation" in the "-(IBAction)" when the map is visible contains the right values. How can I manage it to have my coordinates before the view load? I need them to center the view concerning the own position and the position given by me. MKCoordinateRegion region; region.center.latitude = (storedLocation.latitude + 45.58058)/2.0; region.center.longitude = (storedLocation.longitude - 0.546835)/2.0; region.span.latitudeDelta = ABS(storedLocation.latitude - 45.58058); region.span.longitudeDelta = ABS(storedLocation.longitude + 0.546835); [mapView setRegion:region animated:TRUE];

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  • How to solve Python memory leak when using urrlib2?

    - by b_m
    Hi, I'm trying to write a simple Python script for my mobile phone to periodically load a web page using urrlib2. In fact I don't really care about the server response, I'd only like to pass some values in the URL to the PHP. The problem is that Python for S60 uses the old 2.5.4 Python core, which seems to have a memory leak in the urrlib2 module. As I read there's seems to be such problems in every type of network communications as well. This bug have been reported here a couple of years ago, while some workarounds were posted as well. I've tried everything I could find on that page, and with the help of Google, but my phone still runs out of memory after ~70 page loads. Strangely the Garbege Collector does not seem to make any difference either, except making my script much slower. It is said that, that the newer (3.1) core solves this issue, but unfortunately I can't wait a year (or more) for the S60 port to come. here's how my script looks after adding every little trick I've found: import urrlib2, httplib, gc while(true): url = "http://something.com/foo.php?parameter=" + value f = urllib2.urlopen(url) f.read(1) f.fp._sock.recv=None # hacky avoidance f.close() del f gc.collect() Any suggestions, how to make it work forever without getting the "cannot allocate memory" error? Thanks for advance, cheers, b_m update: I've managed to connect 92 times before it ran out of memory, but It's still not good enough. update2: Tried the socket method as suggested earlier, this is the second best (wrong) solution so far: class UpdateSocketThread(threading.Thread): def run(self): global data while 1: url = "/foo.php?parameter=%d"%data s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.connect(('something.com', 80)) s.send('GET '+url+' HTTP/1.0\r\n\r\n') s.close() sleep(1) I tried the little tricks, from above too. The thread closes after ~50 uploads (the phone has 50MB of memory left, obviously the Python shell has not.) UPDATE: I think I'm getting closer to the solution! I tried sending multiple data without closing and reopening the socket. This may be the key since this method will only leave one open file descriptor. The problem is: import socket s=socket.socket(socket.AF_INET, socket.SOCK_STREAM) socket.connect(("something.com", 80)) socket.send("test") #returns 4 (sent bytes, which is cool) socket.send("test") #4 socket.send("test") #4 socket.send("GET /foo.php?parameter=bar HTTP/1.0\r\n\r\n") #returns the number of sent bytes, ok socket.send("GET /foo.php?parameter=bar HTTP/1.0\r\n\r\n") #returns 0 on the phone, error on Windows7* socket.send("GET /foo.php?parameter=bar HTTP/1.0\r\n\r\n") #returns 0 on the phone, error on Windows7* socket.send("test") #returns 0, strange... *: error message: 10053, software caused connection abort Why can't I send multiple messages??

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  • UTF-8 GET using Indy 10.5.8.0 and Delphi XE2

    - by Bogdan Botezatu
    I'm writing my first Unicode application with Delphi XE2 and I've stumbled upon an issue with GET requests to an Unicode URL. Shortly put, it's a routine in a MP3 tagging application that takes a track title and an artist and queries Last.FM for the corresponding album, track no and genre. I have the following code: function GetMP3Info(artist, track: string) : TMP3Data //<---(This is a record) var TrackTitle, ArtistTitle : WideString; webquery : WideString; [....] WebQuery := UTF8Encode('http://ws.audioscrobbler.com/2.0/?method=track.getcorrection&api_key=' + apikey + '&artist=' + artist + '&track=' + track); //[processing the result in the web query, getting the correction for the artist and title] // eg: for artist := Bucovina and track := Mestecanis, the corrected values are //ArtistTitle := Bucovina; // TrackTitle := Mestecani?; //Now here is the tricky part: webquery := UTF8Encode('http://ws.audioscrobbler.com/2.0/?method=track.getInfo&api_key=' + apikey + '&artist=' + unescape(ArtistTitle) + '&track=' + unescape(TrackTitle)); //the unescape function replaces spaces (' ') with '+' to comply with the last.fm requests [some more processing] end; The webquery looks in a TMemo just right (http://ws.audioscrobbler.com/2.0/?method=track.getInfo&api_key=e5565002840xxxxxxxxxxxxxx23b98ad&artist=Bucovina&track=Mestecani?) Yet, when I try to send a GET() to the webquery using IdHTTP (with the ContentEncoding property set to 'UTF-8'), I see in Wireshark that the component is GET-ing the data to the ANSI value '/2.0/?method=track.getInfo&api_key=e5565002840xxxxxxxxxxxxxx23b98ad&artist=Bucovina&track=Mestec?ni?' Here is the full headers for the GET requests and responses: GET /2.0/?method=track.getInfo&api_key=e5565002840xxxxxxxxxxxxxx23b98ad&artist=Bucovina&track=Mestec?ni? HTTP/1.1 Content-Encoding: UTF-8 Host: ws.audioscrobbler.com Accept: text/html, */* Accept-Encoding: identity User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.23) Gecko/20110920 Firefox/3.6.23 SearchToolbar/1.22011-10-16 20:20:07 HTTP/1.0 400 Bad Request Date: Tue, 09 Oct 2012 20:46:31 GMT Server: Apache/2.2.22 (Unix) X-Web-Node: www204 Access-Control-Allow-Origin: * Access-Control-Allow-Methods: POST, GET, OPTIONS Access-Control-Max-Age: 86400 Cache-Control: max-age=10 Expires: Tue, 09 Oct 2012 20:46:42 GMT Content-Length: 114 Connection: close Content-Type: text/xml; charset=utf-8; <?xml version="1.0" encoding="utf-8"?> <lfm status="failed"> <error code="6"> Track not found </error> </lfm> The question that puzzles me is am I overseeing anything related to setting the property of the tidhttp control? How can I stop the well-formated URL i'm composing in the application from getting wrongfully sent to the server? Thanks.

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  • Serious Memory Clash: Variables clashing in C

    - by Soham
    int main(int argc, char*argv[]) { Message* newMessage; Asset* Check; //manipulation and initialization of Check, so that it holds proper values. newMessage = parser("N,2376,01/02/2011 09:15:01.342,JPASSOCIAT FUTSTK 24FEB2011,B,84.05,2000,0,0",newMessage); // MessageProcess(newMessage,AssetMap); printf("LAST TRADE ADDRESS %p LAST TRADE TIME %s\n",Check->TradeBook,Check->Time); } Message* parser(char *message,Message* new_Message) { char a[9][256]; char* tmp =message; bool inQuote=0; int counter=0; int counter2=0; new_Message = (Message*)malloc(sizeof(Message)); while(*tmp!='\0') { switch(*tmp) { case ',': if(!inQuote) { a[counter][counter2]='\0'; counter++; counter2=0; } break; case '"': inQuote=!inQuote; break; default: a[counter][counter2]=*tmp; counter2++; break; } tmp++; } a[counter][counter2]='\0'; new_Message->type = *a[0]; new_Message->Time = &a[2][11]; new_Message->asset = a[3]; if(*a[4]=='S') new_Message->BS = 0; else new_Message->BS = 1; new_Message->price1=atof(a[5]); new_Message->shares1=atol(a[6]); new_Message->price2=atof(a[7]); new_Message->shares2=atol(a[8]); new_Message->idNum = atoi(a[1]); return(new_Message); } Here there is a serious memory clash, in two variables of different scope. I have investigated using gdb and it seems the address of new_Message->Time is equalling to the address of Check->Time. They both are structures of different types I am trying to resolve this issue, because, when parser changes the value of new_Message->Time it manipulates the contents of Check-Time Please do suggest how to solve this problem. I have lost(spent) around 10 hours and counting to resolve this issue, and tons of hair. Soham

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  • Error while sending email to Multiple Addresses From MYSQL Database using PHP

    - by user1751581
    I am trying to send an email to multiple email addresses which are contained in a database and sorted into a recordset... The recordset has multiple columns, but I only need one: "Email". I know that if I have them in an array I can implode them and separate them by commas, but I'm not sure how I could do that with a recordset column. Anyone know how? BTW I know I have the mail function commented out... The echo is returning null... Heres the code that I tried: $colname_rsAllLeads = "-1"; if (isset($_SESSION['MM_Username'])) { $colname_rsAllLeads = $_SESSION['MM_Username']; } mysql_select_db($database_myBackOfficeConn, $myBackOfficeConn); $query_rsAllLeads = sprintf("SELECT Email FROM Leads WHERE `User` = %s ORDER BY FullName ASC", GetSQLValueString($colname_rsAllLeads, "text")); $rsAllLeads = mysql_query($query_rsAllLeads, $myBackOfficeConn) or die(mysql_error()); $row_rsAllLeads = mysql_fetch_assoc($rsAllLeads); $totalRows_rsAllLeads = mysql_num_rows($rsAllLeads); $editFormAction = $_SERVER['PHP_SELF']; if (isset($_SERVER['QUERY_STRING'])) { $editFormAction .= "?" . htmlentities($_SERVER['QUERY_STRING']); } if ((isset($_POST["MM_insert"])) && ($_POST["MM_insert"] == "form")) { $startcode = $_POST['messagefield']; $replaced = preg_replace( '/\\\\(?="|\')/', '', $startcode ); echo $replaced; $collectedleads = implode(',', $row_rsAllLeads['Email']); echo $collectedleads; /* $to = $collectedleads; $subject = $_POST['subjectfield']; $body = $replaced; $headers = "MIME-Version: 1.0\r\n"; $headers .= "Content-type: text/html; charset=iso-8859-1\r\n"; $headers .= "From: " . $row_rs_CurrentUser['FirstName'] . " " . $row_rs_CurrentUser['LastName'] . " <" . $row_rs_CurrentUser['Email'] . ">"; if (mail($to, $subject, $body, $headers)) { } else { echo("<p>Message delivery failed...</p>"); } */ $insertSQL = sprintf("INSERT INTO PendingEmails (`to`, subject, message) VALUES (%s, %s, %s)", GetSQLValueString($row_rsAllLeads['Email'], "text"), GetSQLValueString($_POST['subjectfield'], "text"), GetSQLValueString($_POST['messagefield'], "text")); mysql_select_db($database_myBackOfficeConn, $myBackOfficeConn); $Result1 = mysql_query($insertSQL, $myBackOfficeConn) or die(mysql_error()); $insertGoTo = "Email Sent.php"; if (isset($_SERVER['QUERY_STRING'])) { $insertGoTo .= (strpos($insertGoTo, '?')) ? "&" : "?"; $insertGoTo .= $_SERVER['QUERY_STRING']; } header(sprintf("Location: %s", $insertGoTo)); } When I use var_dump($row_rsAllLeads['Email']) it outputs string(16) "[email protected]" but I know that there is no error in my SQL query because when I put them in a select box, they all show up...

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  • php paypal ipn membership error

    - by aleksander haugas
    hello I integrated the membership subscription in the website, but I fail to insert data to the database. checking out all the function I make a txt file with php with data and generates me correctly. but I can not verify any data and less insert. <?php // read the post from PayPal system and add 'cmd' $req = 'cmd=_notify-validate'; foreach ($_POST as $key => $value) { $value = urlencode(stripslashes($value)); $req .= "&$key=$value"; } // Post back to PayPal system to validate $header .= "POST /cgi-bin/webscr HTTP/1.0\r\n"; $header .= "Content-Type: application/x-www-form-urlencoded\r\n"; $header .= "Content-Length: " . strlen($req) . "\r\n\r\n"; $fp = fsockopen ('ssl://www.paypal.com', 443, $errno, $errstr, 30); // Assign posted variables to local variables $item_name = $_POST['item_name']; $item_number = $_POST['item_number']; $payment_status = $_POST['payment_status']; $payment_amount = $_POST['mc_gross']; $payment_currency = $_POST['mc_currency']; $txn_id = $_POST['txn_id']; $receiver_email = $_POST['receiver_email']; $payer_email = $_POST['payer_email']; $user_id = $_POST['custom']; //Here i make the txt file and it works correctly //but after this does not work or make a txt file //Insert and update data if (!$fp) { // HTTP ERROR } else { fputs ($fp, $header . $req); while (!feof($fp)) { $res = fgets ($fp, 1024); if (strcmp ($res, "VERIFIED") == 0) { //Verificamos el estado del pedido if ($payment_status == 'Completed') { $txn_id_check = mysql_query("SELECT Transaction_ID FROM ".$db_table_prefix."Users_Payments WHERE Transaction_ID='".$txn_id."'"); if (mysql_num_rows($txn_id_check) !=1) { //Si el pago se ha realizado al dueño especificado y coincide con el dueño if ($receiver_email == $website_Payment_Email) { //Tipo de cuenta segun pagado if ($payment_amount == '10.00' && $payment_currency == 'EUR') { //add txn_id to database $log_query = mysql_query("INSERT INTO `".$db_table_prefix."Users_Payments` VALUES ('','".$txn_id."','".$payer_email."')"); //update premium to 3 $update_premium = mysql_query("UPDATE ".$db_table_prefix."Users SET Group_ID='3' WHERE User_ID='".$user_id."'"); } } } } } else if (strcmp ($res, "INVALID") == 0) { // log for manual investigation } } fclose ($fp); } ?> I call this file with require_once () with the connection to the database any ideas? thanks

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  • Stored procedure error when use computed column for ID

    - by Hari
    I got the error: Procedure or function usp_User_Info3 has too many arguments specified When I run the program. I don't know the error in SP or in C# code. I have to display the Vendor_ID after the user clicks the submit button. Where the thing going wrong here ? Table structure : CREATE TABLE User_Info3 ( SNo int Identity (2000,1) , Vendor_ID AS 'VEN' + CAST(SNo as varchar(16)) PERSISTED PRIMARY KEY, UserName VARCHAR(16) NOT NULL, User_Password VARCHAR(12) NOT NULL, User_ConPassword VARCHAR(12) NOT NULL, User_FirstName VARCHAR(25) NOT NULL, User_LastName VARCHAR(25) SPARSE NULL, User_Title VARCHAR(35) NOT NULL, User_EMail VARCHAR(35) NOT NULL, User_PhoneNo VARCHAR(14) NOT NULL, User_MobileNo VARCHAR(14)NOT NULL, User_FaxNo VARCHAR(14)NOT NULL, UserReg_Date DATE DEFAULT GETDATE() ) Stored Procedure : ALTER PROCEDURE [dbo].[usp_User_Info3] @SNo INT OUTPUT, @Vendor_ID VARCHAR(10) OUTPUT, @UserName VARCHAR(30), @User_Password VARCHAR(12), @User_ConPassword VARCHAR(12), @User_FirstName VARCHAR(25), @User_LastName VARCHAR(25), @User_Title VARCHAR(35), @User_OtherEmail VARCHAR(30), @User_PhoneNo VARCHAR(14), @User_MobileNo VARCHAR(14), @User_FaxNo VARCHAR(14) AS BEGIN SET NOCOUNT ON; INSERT INTO User_Info3 (UserName,User_Password,User_ConPassword,User_FirstName, User_LastName,User_Title,User_OtherEmail,User_PhoneNo,User_MobileNo,User_FaxNo) VALUES (@UserName,@User_Password,@User_ConPassword,@User_FirstName,@User_LastName, @User_Title,@User_OtherEmail,@User_PhoneNo,@User_MobileNo,@User_FaxNo) SET @SNo = Scope_Identity() SELECT Vendor_ID From User_Info3 WHERE SNo = @SNo END C# Code : protected void BtnUserNext_Click(object sender, EventArgs e) { cmd.CommandType = CommandType.StoredProcedure; cmd.CommandText = "usp_User_Info3"; System.Data.SqlClient.SqlParameter SNo=cmd.Parameters.Add("@SNo",System.Data.SqlDbType.Int); System.Data.SqlClient.SqlParameter Vendor_ID=cmd.Parameters.Add("@Vendor_ID", System.Data.SqlDbType.VarChar,10); cmd.Parameters.Add("@UserName", SqlDbType.VarChar).Value = txtUserName.Text; cmd.Parameters.Add("@User_Password", SqlDbType.VarChar).Value = txtRegPassword.Text; cmd.Parameters.Add("@User_ConPassword", SqlDbType.VarChar).Value = txtRegConPassword.Text; cmd.Parameters.Add("@User_FirstName", SqlDbType.VarChar).Value = txtRegFName.Text; cmd.Parameters.Add("@User_LastName", SqlDbType.VarChar).Value = txtRegLName.Text; cmd.Parameters.Add("@User_Title", SqlDbType.VarChar).Value = txtRegTitle.Text; cmd.Parameters.Add("@User_OtherEmail", SqlDbType.VarChar).Value = txtOtherEmail.Text; cmd.Parameters.Add("@User_PhoneNo", SqlDbType.VarChar).Value =txtRegTelephone.Text; cmd.Parameters.Add("@User_MobileNo", SqlDbType.VarChar).Value =txtRegMobile.Text; cmd.Parameters.Add("@User_FaxNo", SqlDbType.VarChar).Value =txtRegFax.Text; cmd.Connection = SqlCon; try { Vendor_ID.Direction = System.Data.ParameterDirection.Output; SqlCon.Open(); cmd.ExecuteNonQuery(); string VendorID = cmd.ExecuteScalar() as string; } catch (Exception ex) { throw new Exception(ex.Message); } finally { string url = "../CompanyBasicInfo.aspx?Parameter=" + Server.UrlEncode(" + VendorID + "); SqlCon.Close(); } }

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  • Accessing Content Page elements

    - by Abdel Olakara
    Hi all, I am facing a strange problem.. may be i am overlooking something and not able to find the silly issue. Need your help! I have a Master page and a Content Page: <form id="AccountForm" runat="server"> <div> <asp:ContentPlaceHolder ID="MenuHolder" runat="server"> </asp:ContentPlaceHolder> </div> <hr /> <div> <asp:ContentPlaceHolder ID="ContentHolder" runat="server"> </asp:ContentPlaceHolder> </div> And my content page has some form elements: <asp:Content ID="Content3" ContentPlaceHolderID="ContentHolder" runat="server"> First Name: <asp:TextBox ID="fName" runat="server"></asp:TextBox> <br /> Middle Name: <asp:TextBox ID="mName" runat="server"></asp:TextBox> <br /> Family Name: <asp:TextBox ID="lName" runat="server"></asp:TextBox> <br /> Birthday: <asp:TextBox ID="birthday" runat="server"></asp:TextBox> <br /> Mobile Phone: <asp:TextBox ID="mobile" runat="server"></asp:TextBox> <br /> Alternate Phone: <asp:TextBox ID="phone" runat="server"></asp:TextBox> <br /> I also have the code for submit button in the content page where i try to retrieve the values from the form elements and persist it into DB. Here is the SubmitButton_Click code: protected void SubmitButton_Click(object sender, EventArgs e) { log.Info("From Submit button: " + customerObject.first_name + " " + customerObject.family_name); if (fName != null) log.Info("First Name is not null"); log.Info("First Name:" + fName.Text); log.Info("Middle Name:" + mName.Text); log.Info("Family Name:" + fName.Text); log.Info("Mobile:" + mobile.Text); log.Info("Phone: " + phone.Text); log.Info("Address:" + bAddressL1.Text + bAddressL2.Text); Strangly.. i don't get any data that is filled into my text fields? Their objects are not null as well!! why is this behaviour happening? I am not trying to access elements in master page or other.. all the fields are in the content page.. only thing is there is no form element in the content page and the form element is in master page! Thanks in advance for your suggestions and answers. Abdel Raoof Olakara

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  • Unmanaged Code calling leads to heavy memory leak!!

    - by konnychen
    Maybe I need change the title as "Unmanaged Code calling leads to heavy memory leak!" The leak is around 30M/hour I think maybe I need complete my code here because the memory leak maybe not from a static string whereas my real code derive this string from external device (see new code attached). so I handle also unmanaged code. Could it be possible the leak comes from unmanaged code? But I freed the resouce by Marshal.FreeCoTaskMem(pos); oThread2 = new Thread(new ThreadStart(Cyclic_Call)); oThread2.Start(); delegate void SetText_lab_Statubar(string text); private void m_SetText_lab_Statubar(string text) { if (this.lab_Statubar.InvokeRequired) { SetText_lab_Statubar d = new SetText_lab_Statubar(m_SetText_lab_Statubar); this.Invoke(d, new object[] { text }); } else { this.lab_Statubar.Text = text; } } private void Cyclic_Call() { do { //... ... ReadMatrixCode(Station6, 0, str_Code); this.m_SetText_lab_Statubar(str_Code[4]); Thread.Sleep(100); } while (!b_AbortThraed); } private void ReadMatrixCode(Station st, int ItemNr, string[] str_Code) { IntPtr pItemStates = IntPtr.Zero; IntPtr pErrors = IntPtr.Zero; int NumItems = itemServerHandles.Length; m_SyncIO.Read(DataSrc, NumItems, itemServerHandles, out pItemStates, out pErrors); // This calls external dll which has some of "out IntPtr" errors = new int[NumItems]; Marshal.Copy(pErrors, errors, 0, NumItems); IntPtr pos = pItemStates; // Now get the read values and check errors for (int dwCount = 0; dwCount < NumItems; dwCount++) { result[dwCount] = (ITEMSTATE)Marshal.PtrToStructure(pos, typeof(ITEMSTATE)); pos = (IntPtr)(pos.ToInt32() + Marshal.SizeOf(typeof(ITEMSTATE))); } // Free allocated COM-ressouces Marshal.FreeCoTaskMem(pItemStates); Marshal.FreeCoTaskMem(pErrors); pItemStates = IntPtr.Zero; pErrors = IntPtr.Zero; } m_syncIO is a class and finally it will call COM component which is defined below [Guid("39C12B52-011E-11D0-9675-1020AFD8ADB3")] [InterfaceType(1)] [ComConversionLoss] public interface ISyncIO { void Read(DATASOURCE dwSource, int dwCount, int[] phServer, out IntPtr ppItemValues, out IntPtr ppErrors); void Write(int dwCount, int[] phServer, object[] pItemValues, out IntPtr ppErrors); }

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  • SQL Server 2005 - query with case statement

    - by user329266
    Trying to put a single query together to be used eventually in a SQL Server 2005 report. I need to: Pull in all distinct records for values in the "eventid" column for a time frame - this seems to work. For each eventid referenced above, I need to search for all instances of the same eventid to see if there is another record with TaskName like 'review1%'. Again, this seems to work. This is where things get complicated: For each record where TaskName is like review1, I need to see if another record exists with the same eventid and where TaskName='End'. Utimately, I need a count of how many records have TaskName like 'review1%', and then how many have TaskName like 'review1%' AND TaskName='End'. I would think this could be accomplished by setting a new value for each record, and for the eventid, if a record exists with TaskName='End', set to 1, and if not, set to 0. The query below seems to accomplish item #1 above: SELECT eventid, TimeStamp, TaskName, filepath FROM (SELECT eventid, TimeStamp, filepath, TaskName, ROW_NUMBER() OVER(PARTITION BY eventid ORDER BY TimeStamp DESC) AS seq FROM eventrecords where ((TimeStamp >= '2010-4-1 00:00:00.000') and (TimeStamp <= '2010-4-21 00:00:00.000'))) AS T WHERE seq = 1 order by eventid And the query below seems to accomplish #2: SELECT eventid, TimeStamp, TaskName, filepath FROM (SELECT eventid, TimeStamp, filepath, TaskName, ROW_NUMBER() OVER(PARTITION BY eventid ORDER BY TimeStamp DESC) AS seq FROM eventrecords where ((TimeStamp >= '2010-4-1 00:00:00.000') and (TimeStamp <= '2010-4-21 00:00:00.000')) and TaskName like 'Review1%') AS T WHERE seq = 1 order by eventid This will bring back the eventid's that also have a TaskName='End': SELECT eventid, TimeStamp, TaskName, filepath FROM (SELECT eventid, TimeStamp, filepath, TaskName, ROW_NUMBER() OVER(PARTITION BY eventid ORDER BY TimeStamp DESC) AS seq FROM eventrecords where ((TimeStamp >= '2010-4-1 00:00:00.000') and (TimeStamp <= '2010-4-21 00:00:00.000')) and TaskName like 'Review1%') AS T WHERE seq = 1 and eventid in (Select eventid from eventrecords where TaskName = 'End') order by eventid So I've tried the following to TRY to accomplish #3: SELECT eventid, TimeStamp, TaskName, filepath FROM (SELECT eventid, TimeStamp, filepath, TaskName, ROW_NUMBER() OVER(PARTITION BY eventid ORDER BY TimeStamp DESC) AS seq FROM eventrecords where ((TimeStamp >= '2010-4-1 00:00:00.000') and (TimeStamp <= '2010-4-21 00:00:00.000')) and TaskName like 'Review1%') AS T WHERE seq = 1 and case when (eventid in (Select eventid from eventrecords where TaskName = 'End') then 1 else 0) as bit end order by eventid When I try to run this, I get: "Incorrect syntax near the keyword 'then'." Not sure what I'm doing wrong. Haven't seen any examples anywhere quite like this. I should mention that eventrecords has a primary key, but it doesn't seem to help anything when I include it, and I am not permitted to change the table. (ugh) I've received one suggestion to use a cursor and temporary table, but am not sure how badley that would bog down performance when the report is running. Thanks in advance.

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  • how to use jquery autocomplete?

    - by kyrogue
    hi, i am creating a web project using JSP, and is trying to implement a simple search for users from my database using jquery autocomplete, however i am having trouble understanding how it works. i have little to no knowledge on jquery and ajax just to let you know. i have done the following code and am stuck. <%@page contentType="text/html" pageEncoding="UTF-8" import="ewa.dbConnect,ewa.sendEmail,ewa.pwGen,ewa.hashPw,java.sql.*" %> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <link rel="stylesheet" type="text/css" href="css/jquery.autocomplete.css" /> <script src="js/jquery.autocomplete.js"></script> <script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.4.4/jquery.min.js"></script> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>JSP Page</title> </head> <body> <input type="text" id="search" name="search"/> <script> $("#search").autocomplete("getdata.jsp"); </script> </body> </html> <%@page contentType="text/html" pageEncoding="UTF-8" import="ewa.dbConnect,java.sql.*" %> <%! dbConnect db = new dbConnect(); %> <% String query = request.getParameter("q"); db.connect(); Statement stmt = db.getConnection().createStatement(); ResultSet rs = stmt.executeQuery("SELECT username FROM created_accounts WHERE username LIKE "+query); while(rs.next()) { out.println(rs.getString("username")); } db.disconnect %> if i am not wrong i read from a website, the parameter q is default and is just there, however how do i display the data? how do i pass the values from getdata.jsp into the autocomplete?

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  • select option in Safari ?

    - by Karandeep Singh
    < select size="2" multiple> < option value="1">1< /option> < option value="2">2< /option> < option value="3">3< /option> < option value="4">4< /option> < option value="5">5< /option> < option value="6">6< /option> < option value="7">7< /option> < option value="8">8< /option> < option value="9">9< /option> < option value="10">10< /option> < option value="11">11< /option> < option value="12">12< /option> < option value="13">13< /option> < /select> size attribute of Select tag is not working properly in Safari. if size attribute's value is greater than four then there have no problem, its working. But when I set the value of size less than four then it show four values. above example displays four options in safari but I want two options. What is the reason for this ?

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  • Python. How to iterate through a list of lists looking for a partial match

    - by Becca Millard
    I'm completely stuck on this, without even an idea about how to wrap my head around the logic of this. In the first half of the code, I have successfully generation a list of (thousands of) lists of players names and efficiency scores: eg name_order_list = [["Bob", "Farley", 12.345], ["Jack", "Donalds", 14.567], ["Jack", "Donalds", 13.421], ["Jack", "Donalds", 15.232],["Mike", "Patricks", 10.543]] What I'm trying to do, is come up with a way to make a list of lists of the average efficiency of each player. So in that example, Jack Donalds appears multiple times, so I'd want to recognize his name somehow and average out the efficiency scores. Then sort that new list by efficiency, rather than name. So then the outcome would be like: average_eff_list = [[12.345, "Bob", "Farley"], [14.407, "Jack", "Donalds"], [10.543, "Mike", "Patricks"]] Here's what I tried (it's kind of a mess, but should be readable): total_list = [] odd_lines = [name_order_list[i] for i in range(len(name_order_list)) if i % 2 == 0] even_lines = [name_order_list[i] for i in range(len(name_order_list)) if i % 2 == 1] i = 0 j = i-1 while i <= 10650: iteration = 2 total_eff = 0 while odd_lines[i][0:2] == even_lines[i][0:2]: if odd_lines[i][0:2] == even_lines[j][0:2]: if odd_lines[j][0:2] != even_lines[j][0:2]: total_eff = even_lines[j][2]/(iteration-1) iteration -= 1 #account fr the single (rather than dual) additional entry else: total_eff = total_eff if iteration == 2: total_eff = (odd_lines[i][2] + even_lines[i][2]) / iteration else: total_eff = ((total_eff * (iteration - 2)) + (odd_lines[i][2] + even_lines[i][2])) / iteration iteration += 2 i += 1 j += 1 if i > 10650: break else: if odd_lines[i][0:2] == even_lines[j][0:2]: if odd_lines[j][0:2] != even_lines[j][0:2]: total_eff = (odd_lines[i][2] + even_lines[j][2]) / iteration else: total_eff = ((total_eff * (iteration -2)) + odd_lines[i][2]) / (iteration - 1) if total_eff == 0: #there's no match at all total_odd = [odd_lines[i][2], odd_lines[i][0], odd_lines[i][1]] total_list.append(total_odd) if even_lines[i][0:2] != odd_lines[i+1][0:2]: total_even = [even_lines[i][2], even_lines[i][0], even_lines[i][1]] else: total = [total_eff, odd_lines[i][0], odd_lines[i][1]] total_list.append(total) i += 1 if i > 10650: break else: print(total_list) Now, this runs well enough (doesn't get stuck or print someone's name multiple times) but the efficiency values are off by a large amount, so I know that scores are getting missed somewhere. This is a problem with my logic, I think, so any help would be greatly appreciated. As would any advice about how to loop through that massive list in a smarter way, since I'm sure there is one... EIDT: for this exercise, I need to keep it all in a list format. I can make new lists, but no using dictionaries, classes, etc.

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  • What benefits are there to storing Javascript in external files vs in the <head>?

    - by RenderIn
    I have an Ajax-enabled CRUD application. If I display a record from my database it shows that record's values for each column, including its primary key. For the Ajax actions tied to buttons on the page I am able to set up their calls by printing the ID directly into their onclick functions when rendering the HTML server-side. For example, to save changes to the record I may have a button as follows, with '123' being the primary key of the record. <button type="button" onclick="saveRecord('123')">Save</button> Sometimes I have pages with Javascript generating HTML and Javascript. In some of these cases the primary key is not naturally available at that place in the code. In these cases I took a shortcut and generate buttons like so, taking the primary key from a place it happens to be displayed on screen for visual consumption: ... <td>Primary Key: </td> <td><span id="PRIM_KEY">123</span></td> ... <button type="button" onclick="saveRecord(jQuery('#PRIM_KEY').text())">DoSomething</button> This definitely works, but it seems wrong to drive database queries based on the value of text whose purpose was user consumption rather than method consumption. I could solve this by adding a series of additional parameters to various methods to usher the primary key along until it is eventually needed, but that also seems clunky. The most natural way for me to solve this problem would be to simply situate all the Javascript which currently lives in external files, in the <head> of the page. In that way I could generate custom Javascript methods without having to pass around as many parameters. Other than readability, I'm struggling to see what benefit there is to storing Javascript externally. It seems like it makes the already weak marriage between HTML/DOM and Javascript all the more distant. I've seen some people suggest that I leave the Javascript external, but do set various "custom" variables on the page itself, for example, in PHP: <script type="text/javascript"> var primaryKey = <?php print $primaryKey; ?>; </script> <script type="text/javascript" src="my-external-js-file-depending-on-primaryKey-being-set.js"></script> How is this any better than just putting all the Javascript on the page in the first place? There HTML and Javascript are still strongly dependent on each other.

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  • Box Shadow on only 3 sides

    - by Connor
    I have two overlapping divs that have css3 box shadows. The trouble is that even when I set the z-index I will still need to eliminate one of the div's box-shadow. I have seen cases where negative spreads and zero values are used but I don't think that would work here. The code I have now is: #bulb-top { position: relative; width: 280px; height: 280px; background-color: #E5F7A3; -webkit-border-radius: 280px; -moz-border-radius: 280px; border-radius: 280px; border: 8px solid #FFF40C; top: -430px; margin-left: auto; margin-right: auto; -webkit-box-shadow: 0px 0px 15px 1px #FFF40C; -moz-box-shadow: 0px 0px 15px 1px #FFF40C; box-shadow: 0px 0px 15px 1px #FFF40C; z-index: 4; } #bulb-bottom { position: relative; width: 140px; height: 120px; background-color: #E5F7A3; -moz-border-radius-topleft: 0px; -moz-border-radius-topright: 0px; -moz-border-radius-bottomright: 30px; -moz-border-radius-bottomleft: 30px; -webkit-border-radius: 0px 0px 30px 30px; border-radius: 0px 0px 30px 30px; border-left: 8px solid #FFF40C; border-right: 8px solid #FFF40C; border-bottom: 8px solid #FFF40C; top: -455px; margin-left: auto; margin-right: auto; -webkit-box-shadow: 0px 0px 15px 1px #FFF40C; -moz-box-shadow: 0px 0px 15px 1px #FFF40C; box-shadow: 0px 0px 15px 1px #FFF40C; z-index: 5; } http://jsfiddle.net/minitech/g42vq/3/

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  • PHP 5.2 Function needed for GENERIC sorting of a recordset array

    - by donbriggs
    Somebody must have come up with a solution for this by now. We are using PHP 5.2. (Don't ask me why.) I wrote a PHP class to display a recordset as an HTML table/datagrid, and I wish to expand it so that we can sort the datagrid by whichever column the user selects. In the below example data, we may need to sort the recordset array by Name, Shirt, Assign, or Age fields. I will take care of the display part, I just need help with sorting the data array. As usual, I query a database to get a result, iterate throught he result, and put the records into an assciateiave array. So, we end up with an array of arrays. (See below.) I need to be able to sort by any column in the dataset. However, I will not know the column names at design time, nor will I know if the colums will be string or numeric values. I have seen a ton of solutions to this, but I have not seen a GOOD and GENERIC solution Can somebody please suggest a way that I can sort the recordset array that is GENERIC, and will work on any recordset? Again, I will not know the fields names or datatypes at design time. The array presented below is ONLY an example. UPDATE: Yes, I would love to have the database do the sorting, but that is just not going to happen. The queries that we are running are very complex. (I am not really querying a table of Star Trek characters.) They include joins, limits, and complex WHERE clauses. Writing a function to pick apart the SQL statement to add an ORDER BY is really not an option. Besides, sometimes we already have the array that is a result of the query, rather than the ability to run a new query. Array ( [0] => Array ( [name] => Kirk [shrit] => Gold [assign] => Bridge ) [1] => Array ( [name] => Spock [shrit] => Blue [assign] => Bridge ) [2] => Array ( [name] => Uhura [shrit] => Red [assign] => Bridge ) [3] => Array ( [name] => Scotty [shrit] => Red [assign] => Engineering ) [4] => Array ( [name] => McCoy [shrit] => Blue [assign] => Sick Bay ) )

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  • Opinion on "loop invariants", and are these frequently used in the industry?

    - by Michael Aaron Safyan
    I was thinking back to my freshman year at college (five years ago) when I took an exam to place-out of intro-level computer science. There was a question about loop invariants, and I was wondering if loop invariants are really necessary in this case or if the question was simply a bad example... the question was to write an iterative definition for a factorial function, and then to prove that the function was correct. The code that I provided for the factorial function was as follows: public static int factorial(int x) { if ( x < 0 ){ throw new IllegalArgumentException("Parameter must be = 0"); }else if ( x == 0 ){ return 1; }else{ int result = 1; for ( int i = 1; i <= x; i++ ){ result*=i; } return result; } } My own proof of correctness was a proof by cases, and in each I asserted that it was correct by definition (x! is undefined for negative values, 0! is 1, and x! is 1*2*3...*x for a positive value of x). The professor wanted me to prove the loop using a loop invariant; however, my argument was that it was correct "by definition", because the definition of "x!" for a positive integer x is "the product of the integers from 1... x", and the for-loop in the else clause is simply a literal translation of this definition. Is a loop invariant really needed as a proof of correctness in this case? How complicated must a loop be before a loop invariant (and proper initialization and termination conditions) become necessary for a proof of correctness? Additionally, I was wondering... how often are such formal proofs used in the industry? I have found that about half of my courses are very theoretical and proof-heavy and about half are very implementation and coding-heavy, without any formal or theoretical material. How much do these overlap in practice? If you do use proofs in the industry, when do you apply them (always, only if it's complicated, rarely, never)?

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  • Killing Mysql prcoesses staying in sleep command.

    - by Shino88
    Hey I am connecting a MYSQL database through hibernate and i seem to have processes that are not being killed after they are finished in the session. I have called flush and close on each session but when i check the server the last processes are still there with a sleep command. This is a new problem which i am having and was not the case yesterday. Is there any way i can ensure the killng of theses processes when i am done with a session. Below is an example of one of my classes. public JSONObject check() { //creates a new session needed to add elements to a database Session session = null; //holds the result of the check in the database JSONObject check = new JSONObject(); try{ //creates a new session needed to add elements to a database SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory(); session = sessionFactory.openSession(); if (justusername){ //query created to select a username from user table String hquery = "Select username from User user Where username = ? "; //query created Query query = session.createQuery(hquery); //sets the username of the query the values JSONObject contents query.setString(0, username); // executes query and adds username string variable String user = (String) query.uniqueResult(); //checks to see if result is found (null if not found) if (user == null) { //adds false to Jobject if not found check.put("indatabase", "false"); } else { check.put("indatabase", "true"); } //adds check to Jobject to say just to check username check.put("justusername", true); } else { //query created to select a username and password from user table String hquery = "Select username from User user Where username = :user and password = :pass "; Query query = session.createQuery(hquery); query.setString("user", username); query.setString("pass", password); String user = (String) query.uniqueResult(); if(user ==null) { check.put("indatabase", false); } else { check.put("indatabase", true); } check.put("justusername", false); } }catch(Exception e){ System.out.println(e.getMessage()); //logg.log(Level.WARNING, " Exception", e.getMessage()); }finally{ // Actual contact insertion will happen at this step session.flush(); session.close(); } //returns Jobject return check; }

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  • Problem in Fetching Table contents when adding rows in same table

    - by jasmine
    Im trying to write a function for adding category: function addCategory() { $cname = mysql_fix_string($_POST['cname']); $kabst = mysql_fix_string($_POST['kabst']); $kselect = $_POST['kselect']; $kradio = $_POST['kradio']; $ksubmit = $_POST['ksubmit']; $id = $_POST['id']; if($ksubmit){ $query = "INSERT INTO category VALUES (' ', '{$cname}', '{$kabst}', {$kselect}, {$kradio}, ' ') "; $result = mysql_query($query); if ($result) { echo "ok"; } else{ echo $query ; } } $text .= '<div class="form"> <h2>ADD new category</h2> <form action="?page=addCategory" method="post"> <ul> <li><label>Category</label></li> <li><input name="cname" type="text" class="inp" /></li> <li><label>Description</label></li> <li><textarea name="kabst" cols="40" rows="10" class="inx"></textarea></li> <li>Published:</li> <li> <select name="kselect" class="ins"> <option value="1">Active</option> <option value="0">Passive</option> </select> </li> <li>Show in home page:</li> <li> <input type="radio" name="kradio" value="1" /> yes <input type="radio" name="kradio" value="0" /> no </li> <li>Subcategory of</li> <li> <select>'; while ($row = mysql_fetch_assoc(mysql_query("SELECT * FROM category"))){ $text .= '<option>'.$row['name'].'</option>'; } $text .= '</select> </li> <li><input name="ksubmit" type="submit" value="ekle" class="int"/></li> </ul> </form> '; return $text;} And the error: Fatal error: Maximum execution time of 30 seconds exceeded What is wrong in my function?

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  • Cross-thread operation not valid: Control accessed from a thread other than the thread it was create

    - by SilverHorse
    I have a scenario. (Windows Forms, C#, .NET) There is a main form which hosts some user control. The user control does some heavy data operation, such that if I directly call the Usercontrol_Load method the UI become nonresponsive for the duration for load method execution. To overcome this I load data on different thread (trying to change existing code as little as I can) I used a background worker thread which will be loading the data and when done will notify the application that it has done its work. Now came a real problem. All the UI (main form and its child usercontrols) was created on the primary main thread. In the LOAD method of the usercontrol I'm fetching data based on the values of some control (like textbox) on userControl. The pseudocode would look like this: //CODE 1 UserContrl1_LOadDataMethod() { if(textbox1.text=="MyName") <<======this gives exception { //Load data corresponding to "MyName". //Populate a globale variable List<string> which will be binded to grid at some later stage. } } The Exception it gave was Cross-thread operation not valid: Control accessed from a thread other than the thread it was created on. To know more about this I did some googling and a suggestion came up like using the following code //CODE 2 UserContrl1_LOadDataMethod() { if(InvokeRequired) // Line #1 { this.Invoke(new MethodInvoker(UserContrl1_LOadDataMethod)); return; } if(textbox1.text=="MyName") //<<======Now it wont give exception** { //Load data correspondin to "MyName" //Populate a globale variable List<string> which will be binded to grid at some later stage } } BUT BUT BUT... it seems I'm back to square one. The Application again become nonresponsive. It seems to be due to the execution of line #1 if condition. The loading task is again done by the parent thread and not the third that I spawned. I don't know whether I perceived this right or wrong. I'm new to threading. How do I resolve this and also what is the effect of execution of Line#1 if block? The situation is this: I want to load data into a global variable based on the value of a control. I don't want to change the value of a control from the child thread. I'm not going to do it ever from a child thread. So only accessing the value so that the corresponding data can be fetched from the database.

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