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  • how to extract data from excel (apache poi) to put it in mysql table using jsp? [ SOLVED]

    - by Nihad KH
    I want to extract data from excel sheet to insert it into a mysql table using jsp, so far i've done this and its printing data into the outpout(using apache poi),what should i add to this code ? Output : Name Age Adress Mark 35 New york,AA Elise 22 India,bb Charlotte 45 France,cc Readexcel.jsp : <%@page import="java.sql.Statement"%> <%@page import="java.util.ArrayList"%> <%@page import="java.sql.PreparedStatement"%> <%@page import="java.sql.Connection"%> <%@page import="java.util.Date"%> <%@page import="org.apache.poi.ss.usermodel.Cell"%> <%@page import="org.apache.poi.ss.usermodel.Row"%> <%@page import="org.apache.poi.xssf.usermodel.XSSFSheet"%> <%@page import="org.apache.poi.xssf.usermodel.XSSFWorkbook"%> <%@page import="java.io.File"%> <%@page import="org.apache.commons.io.FilenameUtils"%> <%@page import="org.apache.commons.fileupload.FileItem"%> <%@page import="java.util.Iterator"%> <%@page import="java.util.List"%> <%@page import="org.apache.commons.fileupload.servlet.ServletFileUpload"%> <%@page import="org.apache.commons.fileupload.disk.DiskFileItemFactory"%> <%@page import="org.apache.commons.fileupload.FileItemFactory"%> <%@page contentType="text/html" pageEncoding="UTF-8"%> <!DOCTYPE html> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>PRINT DATA FROM EXCEL FILE</title> </head> <body> <% try{ boolean ismultipart=ServletFileUpload.isMultipartContent(request); if(!ismultipart){ }else{ FileItemFactory factory = new DiskFileItemFactory(); ServletFileUpload upload = new ServletFileUpload(factory); List items = null; try{ items = upload.parseRequest(request); }catch(Exception e){ } Iterator itr = items.iterator(); while(itr.hasNext()){ FileItem item = (FileItem)itr.next(); if(item.isFormField()){ }else{ String itemname = item.getName(); if((itemname==null || itemname.equals(""))){ continue; } String filename = FilenameUtils.getName(itemname); File f = checkExist(filename); item.write(f); try{ XSSFWorkbook workbook = new XSSFWorkbook(item.getInputStream()); XSSFSheet sheet = workbook.getSheetAt(0); Iterator<Row> rowIterator = sheet.iterator(); while (rowIterator.hasNext()){ Row row = rowIterator.next(); Iterator<Cell> cellIterator = row.cellIterator(); while (cellIterator.hasNext()) { Cell cell = cellIterator.next(); switch (cell.getCellType()){ case Cell.CELL_TYPE_NUMERIC: out.print(cell.getNumericCellValue() + "t"); break; case Cell.CELL_TYPE_STRING: out.print(cell.getStringCellValue() + "t"); break;} } out.println(""); } }catch (Exception e){ e.printStackTrace(); } } } } }catch(Exception e){ } finally { out.close(); } %> <%! private File checkExist(String fileName){ String saveFile = "D:/upload/"; File f = new File(saveFile+"/"+fileName); if(f.exists()){ StringBuffer sb = new StringBuffer(fileName); sb.insert(sb.lastIndexOf("."),"-"+new Date().getTime()); f = new File(saveFile+"/"+sb.toString()); } return f; } %> </body> </html> I've created a table in my database named EXCELDATA with the header of the excel sheet : ExcelData (Name varchar(50),age int,adress varchar(50)); what should i add to this code to get the data from the excel sheet to the mysql table ??

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  • pagination in php error

    - by fusion
    i've implemented this pagination class for my webpage in a separate file called class.pagination.php, but when i execute the page, nothing happens. it just displays a blank page. this is my search.php file, where i'm calling this class: <?php include 'config.php'; require ('class.pagination.php'); $search_result = ""; $search_result = $_GET["q"]; $search_result = trim($search_result); //Check if the string is empty if ($search_result == "") { echo "<p class='error'>Search Error. Please Enter Your Search Query.</p>" ; exit(); } //search query for multiple keywords if(!empty($search_result)) { // the table to search $table = "thquotes"; // explode search words into an array $arraySearch = explode(" ", $search_result); // table fields to search $arrayFields = array(0 => "cQuotes"); $countSearch = count($arraySearch); $a = 0; $b = 0; $query = "SELECT cQuotes, vAuthor, cArabic, vReference FROM ".$table." WHERE ("; $countFields = count($arrayFields); while ($a < $countFields) { while ($b < $countSearch) { $query = $query."$arrayFields[$a] LIKE '%$arraySearch[$b]%'"; $b++; if ($b < $countSearch) { $query = $query." AND "; } } $b = 0; $a++; if ($a < $countFields) { $query = $query.") OR ("; } } $query = $query.")"; $result = mysql_query($query, $conn) or die ('Error: '.mysql_error()); $totalrows = mysql_num_rows($result); if($totalrows < 1) { echo '<span class="error2">No matches found for "'.$search_result.'"</span>'; } else { ?> <div class="caption">Search Results</div> <div class="center_div"> <table> <?php while ($row= mysql_fetch_array($result, MYSQL_ASSOC)) { $cQuote = highlightWords(htmlspecialchars($row['cQuotes']), $search_result); ?> <tr> <td style="text-align:right; font-size:15px;"><?php h($row['cArabic']); ?></td> <td style="font-size:16px;"><?php echo $cQuote; ?></td> <td style="font-size:12px;"><?php h($row['vAuthor']); ?></td> <td style="font-size:12px; font-style:italic; text-align:right;"><?php h($row['vReference']); ?></td> </tr> <?php } ?> </table> </div> <?php } } else { exit(); } //Setting Pagination $pagination = new pagination(); $pagination->byPage = 5; $pagination->rows = $totalrows; // number of records in a table-back mysql_num_rows () instance or another, you have to play $from = $pagination->fromPagination(); // sql used for applications such LIMIT $ from, $ pagination-> byPage $pages = $pagination->pages(); if(isset($pages)) {?> <div class="pagination"> <?foreach ($pages as $key){?> <?if($key['current'] == 1) {?> <a href="?p=<?=$key['p']?>" class="active"><?=$key['page']?></a> <?} else {?> <a href="?p=<?=$key['p']?>" class="inactive"><?=$key['page']?></a> <?}?> <?}?> </div> <?} //End Pagination ?>

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  • Mouse stops working after changing function

    - by heyohletsgo
    I'm making a console board game on c++, and i've been able to make the mouse work in the first function, the menu one, however, when i get to the getmove function and need to click on a house, it simply doesn't work.. Can anyone help? This is the class with the mouse. #include <cstdlib> #include <iostream> #include <process.h> #include <windows.h> #include <time.h> #include <stdio.h> using namespace std; void Game(); int Chu(); int rato(int &row, int &col) { HANDLE hIn; hIn = GetStdHandle(STD_INPUT_HANDLE); bool Continue = TRUE; INPUT_RECORD InRec; DWORD NumRead; HWND window = GetConsoleWindow(); POINT cursorPos; RECT wpos; int x = 0; int y = 0; //cout << hIn << endl; FlushConsoleInputBuffer(hIn); while (Continue) { ReadConsoleInput(hIn, &InRec, 1, &NumRead); switch (InRec.EventType) { case MOUSE_EVENT: if (GetAsyncKeyState(VK_LBUTTON)) { cout << "RATO"<<endl; GetWindowRect(window, &wpos); GetCursorPos(&cursorPos); cursorPos.x -= wpos.left; cursorPos.y -= wpos.top; x = (cursorPos.x - 5) / 16; y = (cursorPos.y - 25) / 24; cout << x << " " << y << endl; row = x; col = y; return row; } else if (GetAsyncKeyState(VK_RBUTTON)){ GetWindowRect(window, &wpos); GetCursorPos(&cursorPos); cursorPos.x -= wpos.left; cursorPos.y -= wpos.top; x = (cursorPos.x - 5) / 16; y = (cursorPos.y - 25) / 24; cout << x << " " << y << endl; row = x; col = y; return row; } break; } } } int main() { cout << "\n\n\n click on the stars" << endl; cout << " \n\n\n *******" << endl; int z = 0; int x = 0; int y = 0; int xo = 0; switch (rato(x,y)) { case 1: Game(); break; case 2: Game(); break; case 3: Game(); break; case 4: rato(x, y); break; case 5: rato(x, y); break; case 6: Game(); break; case 7: Game(); break; case 8: Game(); break; case 9: Game(); break; default: cout << "click again"; break; } return 0; } void Game() { int x = 0; int y = 0; int i = 0; cout << "GAME" << endl; do{ i++; rato(x, y); } while (i <= 2); Chu(); } int Chu() { int x = 0; int y = 0; int a = 0; int b = 0; int xo = 0; int yo = 0; cout << "\ click on the stars" << endl; HANDLE hConsole; hConsole = GetStdHandle(STD_OUTPUT_HANDLE); do{ xo = rato(x, y); if (0 <= xo && xo <= 5) { a = 1;} else cout << "CLICK AGAIN" << endl; } while (xo!=0); cout << a; return a; system("PAUSE"); }

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  • paging php error - undefined index

    - by fusion
    i've a search form with paging. when the user enters the keyword initially, it works fine and displays the required output; however, it also shows this error: Notice: Undefined index: page in C:\Users\user\Documents\Projects\Pro\search.php on line 21 Call Stack: 0.0011 372344 1. {main}() C:\Users\user\Documents\Projects\Pro\search.php:0 . .and if the user clicks on the 'next' page, it shows no output with this error thrown: Notice: Undefined index: q in C:\Users\user\Documents\Projects\Pro\search.php on line 19 Call Stack: 0.0016 372048 1. {main}() C:\Users\user\Documents\Projects\Pro\search.php:0 this is my code: <?php ini_set('display_errors',1); error_reporting(E_ALL|E_STRICT); include 'config.php'; $search_result = ""; $search_result = trim($_GET["q"]); $page= $_GET["page"]; //Get the page number to show if($page == "") $page=1; $search_result = mysql_real_escape_string($search_result); //Check if the string is empty if ($search_result == "") { echo "<p class='error'>Search Error. Please Enter Your Search Query.</p>" ; exit(); } if ($search_result == "%" || $search_result == "_" || $search_result == "+" ) { echo "<p class='error1'>Search Error. Please Enter a Valid Search Query.</p>" ; exit(); } if(!empty($search_result)) { // the table to search $table = "thquotes"; // explode search words into an array $arraySearch = explode(" ", $search_result); // table fields to search $arrayFields = array(0 => "cQuotes"); $countSearch = count($arraySearch); $a = 0; $b = 0; $query = "SELECT cQuotes, vAuthor, cArabic, vReference FROM ".$table." WHERE ("; $countFields = count($arrayFields); while ($a < $countFields) { while ($b < $countSearch) { $query = $query."$arrayFields[$a] LIKE '%$arraySearch[$b]%'"; $b++; if ($b < $countSearch) { $query = $query." AND "; } } $b = 0; $a++; if ($a < $countFields) { $query = $query.") OR ("; } } $query = $query.")"; $result = mysql_query($query, $conn) or die ('Error: '.mysql_error()); $totalrows = mysql_num_rows($result); if($totalrows < 1) { echo '<span class="error2">No matches found for "'.$search_result.'"</span>'; } else { $limit = 3; //Number of results per page $numpages=ceil($totalrows/$limit); $query = $query." ORDER BY idQuotes LIMIT " . ($page-1)*$limit . ",$limit"; $result = mysql_query($query, $conn) or die('Error:' .mysql_error()); ?> <div class="caption">Search Results</div> <div class="center_div"> <table> <?php while ($row= mysql_fetch_array($result, MYSQL_ASSOC)) { $cQuote = highlightWords(htmlspecialchars($row['cQuotes']), $search_result); ?> <tr> <td style="text-align:right; font-size:15px;"><?php h($row['cArabic']); ?></td> <td style="font-size:16px;"><?php echo $cQuote; ?></td> <td style="font-size:12px;"><?php h($row['vAuthor']); ?></td> <td style="font-size:12px; font-style:italic; text-align:right;"><?php h($row['vReference']); ?></td> </tr> <?php } ?> </table> </div> <?php //Create and print the Navigation bar $nav=""; if($page > 1) { $nav .= "<a href=\"search.php?page=" . ($page-1) . "&string=" .urlencode($search_result) . "\"><< Prev</a>"; } for($i = 1 ; $i <= $numpages ; $i++) { if($i == $page) { $nav .= "<B>$i</B>"; }else{ $nav .= "<a href=\"search.php?page=" . $i . "&string=" .urlencode($search_result) . "\">$i</a>"; } } if($page < $numpages) { $nav .= "<a href=\"search.php?page=" . ($page+1) . "&searchstring=" .urlencode($search_result) . "\">Next >></a>"; } echo "<br /><br />" . $nav; } } else { exit(); } ?>

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  • Why this code is not working on linux server ?

    - by user488001
    Hello Experts, I am new in Zend Framework, and this code is use for downloading contents. This code is working in localhost but when i tried to execute in linux server it shows error file not found. public function downloadAnnouncementsAction() { $file= $this-_getParam('file'); $file = str_replace("%2F","/",$this-_getParam('file')); // Allow direct file download (hotlinking)? // Empty - allow hotlinking // If set to nonempty value (Example: example.com) will only allow downloads when referrer contains this text define('ALLOWED_REFERRER', ''); // Download folder, i.e. folder where you keep all files for download. // MUST end with slash (i.e. "/" ) define('BASE_DIR','file_upload'); // log downloads? true/false define('LOG_DOWNLOADS',true); // log file name define('LOG_FILE','downloads.log'); // Allowed extensions list in format 'extension' => 'mime type' // If myme type is set to empty string then script will try to detect mime type // itself, which would only work if you have Mimetype or Fileinfo extensions // installed on server. $allowed_ext = array ( // audio 'mp3' => 'audio/mpeg', 'wav' => 'audio/x-wav', // video 'mpeg' => 'video/mpeg', 'mpg' => 'video/mpeg', 'mpe' => 'video/mpeg', 'mov' => 'video/quicktime', 'avi' => 'video/x-msvideo' ); // If hotlinking not allowed then make hackers think there are some server problems if (ALLOWED_REFERRER !== '' && (!isset($_SERVER['HTTP_REFERER']) || strpos(strtoupper($_SERVER['HTTP_REFERER']),strtoupper(ALLOWED_REFERRER)) === false) ) { die("Internal server error. Please contact system administrator."); } // Make sure program execution doesn't time out // Set maximum script execution time in seconds (0 means no limit) set_time_limit(0); if (!isset($file) || empty($file)) { die("Please specify file name for download."); } // Nullbyte hack fix if (strpos($file, "\0") !== FALSE) die(''); // Get real file name. // Remove any path info to avoid hacking by adding relative path, etc. $fname = basename($file); // Check if the file exists // Check in subfolders too function find_file ($dirname, $fname, &$file_path) { $dir = opendir($dirname); while ($file = readdir($dir)) { if (empty($file_path) && $file != '.' && $file != '..') { if (is_dir($dirname.'/'.$file)) { find_file($dirname.'/'.$file, $fname, $file_path); } else { if (file_exists($dirname.'/'.$fname)) { $file_path = $dirname.'/'.$fname; return; } } } } } // find_file // get full file path (including subfolders) $file_path = ''; find_file(BASE_DIR, $fname, $file_path); if (!is_file($file_path)) { die("File does not exist. Make sure you specified correct file name."); } // file size in bytes $fsize = filesize($file_path); // file extension $fext = strtolower(substr(strrchr($fname,"."),1)); // check if allowed extension if (!array_key_exists($fext, $allowed_ext)) { die("Not allowed file type."); } // get mime type if ($allowed_ext[$fext] == '') { $mtype = ''; // mime type is not set, get from server settings if (function_exists('mime_content_type')) { $mtype = mime_content_type($file_path); } else if (function_exists('finfo_file')) { $finfo = finfo_open(FILEINFO_MIME); // return mime type $mtype = finfo_file($finfo, $file_path); finfo_close($finfo); } if ($mtype == '') { $mtype = "application/force-download"; } } else { // get mime type defined by admin $mtype = $allowed_ext[$fext]; } // Browser will try to save file with this filename, regardless original filename. // You can override it if needed. if (!isset($_GET['fc']) || empty($_GET['fc'])) { $asfname = $fname; } else { // remove some bad chars $asfname = str_replace(array('"',"'",'\\','/'), '', $_GET['fc']); if ($asfname === '') $asfname = 'NoName'; } // set headers header("Pragma: public"); header("Expires: 0"); header("Cache-Control: must-revalidate, post-check=0, pre-check=0"); header("Cache-Control: public"); header("Content-Description: File Transfer"); header("Content-Type: $mtype"); header("Content-Disposition: attachment; filename=\"$asfname\""); header("Content-Transfer-Encoding: binary"); header("Content-Length: " . $fsize); // download // @readfile($file_path); $file = @fopen($file_path,"rb"); if ($file) { while(!feof($file)) { print(fread($file, 1024*8)); flush(); if (connection_status()!=0) { @fclose($file); die(); } } @fclose($file); } // log downloads if (!LOG_DOWNLOADS) die(); $f = @fopen(LOG_FILE, 'a+'); if ($f) { @fputs($f, date("m.d.Y g:ia")." ".$_SERVER['REMOTE_ADDR']." ".$fname."\n"); @fclose($f); } } please Help...

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  • problem in displays data in one page

    - by user318068
    hi ,,,,, I have a problem in the following code ... The following code works as follows displays the invites for each member so that if he had five invite from supposed to be displayed all on one page But before you code that does not function Proper image is the only display one invite on the page and until the approval or rejection of the invitation displays the invite the other .... But this is not my want to offer all on one page I wish I could solve the problem and I can view all calls in one page I think that the problem is in the order code I think that the problem is in the order code my code : <?php session_start(); if (!isset($_SESSION['user_id'])) { header("Location: login.php"); } $id=$_SESSION['user_id']; ?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>Untitled Document</title> </head> <body> <center> <?php include("connect.php"); $sql =mysql_query("select * from ninvite where recieverMemberID ='$id' and viwed= '0'"); $num =mysql_num_rows($sql); echo $num ; if ($num>0) { while($row=mysql_fetch_array($sql)) { $sender=$row['SenderMemberID']; $room=$row['RoomID']; $sql =mysql_query("select MemberName from members where MemberID ='$sender' "); $sql1 =mysql_query("select RoomName from rooms where RoomID ='$room' "); while($row=mysql_fetch_array($sql)) {$mem =$row['MemberName']; } while($rows=mysql_fetch_array($sql1)) { $Ro =$rows['RoomName']; ?> <form action="join.php" method="post"> <label> </label> <br/> <label> <?php echo " you have invite from $mem to join $Ro"; ?> </label> <br/><br/> <label>accept</label> <input name="radio1" type="radio" value="accpet" /> <label>reject</label> <input name="radio1" type="radio" value="Reject" /><br/> <input type="submit" name="submit" value="done" /> </form> <?php } } } ?> </center> </body> </html> thanks alot. my SQl -- phpMyAdmin SQL Dump -- version 3.2.4 -- http://www.phpmyadmin.net -- Host: localhost -- Generation Time: May 07, 2010 at 12:50 ? -- Server version: 5.1.41 -- PHP Version: 5.3.1 SET SQL_MODE="NO_AUTO_VALUE_ON_ZERO"; /*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT /; /!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS /; /!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION /; /!40101 SET NAMES utf8 */; -- -- Database: tr -- -- Table structure for table joinroom CREATE TABLE IF NOT EXISTS joinroom ( MemberID int(10) NOT NULL, RoomID int(10) NOT NULL, PRIMARY KEY (MemberID,RoomID) ) ENGINE=MyISAM DEFAULT CHARSET=latin1; -- -- Dumping data for table joinroom INSERT INTO joinroom (MemberID, RoomID) VALUES (28, 1); -- -- Table structure for table members CREATE TABLE IF NOT EXISTS members ( MemberID int(10) unsigned NOT NULL AUTO_INCREMENT, MemberName varchar(20) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL, MemberPass varchar(10) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL, MemberEmail varchar(30) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL, MemberLocation text CHARACTER SET utf8 COLLATE utf8_bin NOT NULL, MemberImg text CHARACTER SET utf8 COLLATE utf8_bin NOT NULL, PRIMARY KEY (MemberID) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=34 ; -- -- Dumping data for table members INSERT INTO members (MemberID, MemberName, MemberPass, MemberEmail, MemberLocation, MemberImg) VALUES (28, 'marwa', '1234', '[email protected]', 'mmmmmm', 'dddddddddd'), (29, 'nora', '1234', '[email protected]', 'fffffffffffgg', 'gggggggggggggg'), (30, 'soso', '1234', '[email protected]', 'ffffffff', 'kkkkkkkkkkkkkkkkkk'), (31, 'gege', '1234', '[email protected]', 'kkkkkkkkkkkkkkkk', 'uuuuuuuuuuuuuuuuu'), (32, 'nono', '1234', '[email protected]', 'ggggggggggggaaaaa', 'aaaaaaaaaaaaaaa'), (33, 'nda', '1234', '[email protected]', 'kkkkkkkkkkkkkkkk', 'ooooooooooooooo'); -- -- Table structure for table ninvite CREATE TABLE IF NOT EXISTS ninvite ( SenderMemberID int(11) NOT NULL AUTO_INCREMENT, recieverMemberID varchar(30) NOT NULL, RoomID int(11) NOT NULL, viwed int(11) NOT NULL, PRIMARY KEY (SenderMemberID,recieverMemberID,RoomID) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=33 ; -- -- Dumping data for table ninvite INSERT INTO ninvite (SenderMemberID, recieverMemberID, RoomID, viwed) VALUES (28, '33', 1, 0), (28, '32', 1, 0), (28, '31', 1, 0); /*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT /; /!40101 SET CHARACTER_SET_RESULTS=@OLD_CHARACTER_SET_RESULTS /; /!40101 SET COLLATION_CONNECTION=@OLD_COLLATION_CONNECTION */;

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  • setting up linked list Java

    - by erp
    I'm working on some basic linked list stuff, like insert, delete, go to the front or end of the list, and basically i understand the concept of all of that stuff once i have the list i guess but im having trouble setting up the list. I was wondering of you guys could tell me if im going in the right direction. (mostly just the setup) this is what i have so far: public class List { private int size; private List linkedList; List head; List cur; List next; /** * Creates an empty list. * @pre * @post */ public List(){ linkedList = new List(); this.head = null; cur = head; } /** * Delete the current element from this list. The element after the deleted element becomes the new current. * If that's not possible, then the element before the deleted element becomes the new current. * If that is also not possible, then you need to recognize what state the list is in and define current accordingly. * Nothing should be done if a delete is not possible. * @pre * @post */ public void delete(){ // delete size--; } /** * Get the value of the current element. If this is not possible, throw an IllegalArgumentException. * @pre the list is not empty * @post * @return value of the current element. */ public char get(){ return getItem(cur); } /** * Go to the last element of the list. If this is not possible, don't change the cursor. * @pre * @post */ public void goLast(){ while (cur.next != null){ cur = cur.next; } } /** * Advance the cursor to the next element. If this is not possible, don't change the cursor. * @pre * @post */ public void goNext(){ if(cur.next != null){ cur = cur.next;} //else do nothing } /** * Retreat the cursor to the previous element. If this is not possible, don't change the cursor. * @pre * @post */ public void goPrev(){ } /** * Go to top of the list. This is the position before the first element. * @pre * @post */ public void goTop(){ } /** * Go to first element of the list. If this is not possible, don't change the cursor. * @pre * @post */ public void goFirst(){ } /** * Insert the given parameter after the current element. The newly inserted element becomes the current element. * @pre * @post * @param newVal : value to insert after the current element. */ public void insert(char newVal){ cur.setItem(newVal); size++; } /** * Determines if this list is empty. Empty means this list has no elements. * @pre * @post * @return true if the list is empty. */ public boolean isEmpty(){ return head == null; } /** * Determines the size of the list. The size of the list is the number of elements in the list. * @pre * @post * @return size which is the number of elements in the list. */ public int size(){ return size; } public class Node { private char item; private Node next; public Node() { } public Node(char item) { this.item = item; } public Node(char item, Node next) { this.item = item; this.next = next; } public char getItem() { return this.item; } public void setItem(char item) { this.item = item; } public Node getNext() { return this.next; } public void setNext(Node next) { this.next = next; } } } I got the node class alright (well i think it works alright), but is it necessary to even have that class? or can i go about it without even using it (just curious). And for example on the method get() in the list class can i not call that getItem() method from the node class because it's getting an error even though i thought that was the whole point for the node class. bottom line i just wanna make sure im setting up the list right. Thanks for any help guys, im new to linked list's so bear with me!

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  • Inequality joins, Asynchronous transformations and Lookups : SSIS

    - by jamiet
    It is pretty much accepted by SQL Server Integration Services (SSIS) developers that synchronous transformations are generally quicker than asynchronous transformations (for a description of synchronous and asynchronous transformations go read Asynchronous and synchronous data flow components). Notice I said “generally” and not “always”; there are circumstances where using asynchronous transformations can be beneficial and in this blog post I’ll demonstrate such a scenario, one that is pretty common when building data warehouses. Imagine I have a [Customer] dimension table that manages information about all of my customers as a slowly-changing dimension. If that is a type 2 slowly changing dimension then you will likely have multiple rows per customer in that table. Furthermore you might also have datetime fields that indicate the effective time period of each member record. Here is such a table that contains data for four dimension members {Terry, Max, Henry, Horace}: Notice that we have multiple records per customer and that the [SCDStartDate] of a record is equivalent to the [SCDEndDate] of the record that preceded it (if there was one). (Note that I am on record as saying I am not a fan of this technique of storing an [SCDEndDate] but for the purposes of clarity I have included it here.) Anyway, the idea here is that we will have some incoming data containing [CustomerName] & [EffectiveDate] and we need to use those values to lookup [Customer].[CustomerId]. The logic will be: Lookup a [CustomerId] WHERE [CustomerName]=[CustomerName] AND [SCDStartDate] <= [EffectiveDate] AND [EffectiveDate] <= [SCDEndDate] The conventional approach to this would be to use a full cached lookup but that isn’t an option here because we are using inequality conditions. The obvious next step then is to use a non-cached lookup which enables us to change the SQL statement to use inequality operators: Let’s take a look at the dataflow: Notice these are all synchronous components. This approach works just fine however it does have the limitation that it has to issue a SQL statement against your lookup set for every row thus we can expect the execution time of our dataflow to increase linearly in line with the number of rows in our dataflow; that’s not good. OK, that’s the obvious method. Let’s now look at a different way of achieving this using an asynchronous Merge Join transform coupled with a Conditional Split. I’ve shown it post-execution so that I can include the row counts which help to illustrate what is going on here: Notice that there are more rows output from our Merge Join component than on the input. That is because we are joining on [CustomerName] and, as we know, we have multiple records per [CustomerName] in our lookup set. Notice also that there are two asynchronous components in here (the Sort and the Merge Join). I have embedded a video below that compares the execution times for each of these two methods. The video is just over 8minutes long. View on Vimeo  For those that can’t be bothered watching the video I’ll tell you the results here. The dataflow that used the Lookup transform took 36 seconds whereas the dataflow that used the Merge Join took less than two seconds. An illustration in case it is needed: Pretty conclusive proof that in some scenarios it may be quicker to use an asynchronous component than a synchronous one. Your mileage may of course vary. The scenario outlined here is analogous to performance tuning procedural SQL that uses cursors. It is common to eliminate cursors by converting them to set-based operations and that is effectively what we have done here. Our non-cached lookup is performing a discrete operation for every single row of data, exactly like a cursor does. By eliminating this cursor-in-disguise we have dramatically sped up our dataflow. I hope all of that proves useful. You can download the package that I demonstrated in the video from my SkyDrive at http://cid-550f681dad532637.skydrive.live.com/self.aspx/Public/BlogShare/20100514/20100514%20Lookups%20and%20Merge%20Joins.zip Comments are welcome as always. @Jamiet Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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  • Beware when using .NET's named pipes in a windows forms application

    - by FransBouma
    Yesterday a user of our .net ORM Profiler tool reported that he couldn't get the snapshot recording from code feature working in a windows forms application. Snapshot recording in code means you start recording profile data from within the profiled application, and after you're done you save the snapshot as a file which you can open in the profiler UI. When using a console application it worked, but when a windows forms application was used, the snapshot was always empty: nothing was recorded. Obviously, I wondered why that was, and debugged a little. Here's an example piece of code to record the snapshot. This piece of code works OK in a console application, but results in an empty snapshot in a windows forms application: var snapshot = new Snapshot(); snapshot.Record(); using(var ctx = new ORMProfilerTestDataContext()) { var customers = ctx.Customers.Where(c => c.Country == "USA").ToList(); } InterceptorCore.Flush(); snapshot.Stop(); string error=string.Empty; if(!snapshot.IsEmpty) { snapshot.SaveToFile(@"c:\temp\generatortest\test2\blaat.opsnapshot", out error); } if(!string.IsNullOrEmpty(error)) { Console.WriteLine("Save error: {0}", error); } (the Console.WriteLine doesn't do anything in a windows forms application, but you get the idea). ORM Profiler uses named pipes: the interceptor (referenced and initialized in your application, the application to profile) sends data over the named pipe to a listener, which when receiving a piece of data begins reading it, asynchronically, and when properly read, it will signal observers that new data has arrived so they can store it in a repository. In this case, the snapshot will be the observer and will store the data in its own repository. The reason the above code doesn't work in windows forms is because windows forms is a wrapper around Win32 and its WM_* message based system. Named pipes in .NET are wrappers around Windows named pipes which also work with WM_* messages. Even though we use BeginRead() on the named pipe (which spawns a thread to read the data from the named pipe), nothing is received by the named pipe in the windows forms application, because it doesn't handle the WM_* messages in its message queue till after the method is over, as the message pump of a windows forms application is handled by the only thread of the windows forms application, so it will handle WM_* messages when the application idles. The fix is easy though: add Application.DoEvents(); right before snapshot.Stop(). Application.DoEvents() forces the windows forms application to process all WM_* messages in its message queue at that moment: all messages for the named pipe are then handled, the .NET code of the named pipe wrapper will react on that and the whole process will complete as if nothing happened. It's not that simple to just say 'why didn't you use a worker thread to create the snapshot here?', because a thread doesn't get its own message pump: the messages would still be posted to the window's message pump. A hidden form would create its own message pump, so the additional thread should also create a window to get the WM_* messages of the named pipe posted to a different message pump than the one of the main window. This WM_* messages pain is not something you want to be confronted with when using .NET and its libraries. Unfortunately, the way they're implemented, a lot of APIs are leaky abstractions, they bleed the characteristics of the OS objects they hide away through to the .NET code. Be aware of that fact when using them :)

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  • July, the 31 Days of SQL Server DMO’s – Day 22 (sys.dm_db_index_physical_stats)

    - by Tamarick Hill
    The sys.dm_db_index_physical_stats Dynamic Management Function is used to return information about the fragmentation levels, page counts, depth, number of levels, record counts, etc. about the indexes on your database instance. One row is returned for each level in a given index, which we will discuss more later. The function takes a total of 5 input parameters which are (1) database_id, (2) object_id, (3) index_id, (4) partition_number, and (5) the mode of the scan level that you would like to run. Let’s use this function with our AdventureWorks2012 database to better illustrate the information it provides. SELECT * FROM sys.dm_db_index_physical_stats(db_id('AdventureWorks2012'), NULL, NULL, NULL, NULL) As you can see from the result set, there is a lot of beneficial information returned from this DMF. The first couple of columns in the result set (database_id, object_id, index_id, partition_number, index_type_desc, alloc_unit_type_desc) are either self-explanatory or have been explained in our previous blog sessions so I will not go into detail about these at this time. The next column in the result set is the index_depth which represents how deep the index goes. For example, If we have a large index that contains 1 root page, 3 intermediate levels, and 1 leaf level, our index depth would be 5. The next column is the index_level which refers to what level (of the depth) a particular row is referring to. Next is probably one of the most beneficial columns in this result set, which is the avg_fragmentation_in_percent. This column shows you how fragmented a particular level of an index may be. Many people use this column within their index maintenance jobs to dynamically determine whether they should do REORG’s or full REBUILD’s of a given index. The fragment count represents the number of fragments in a leaf level while the avg_fragment_size_in_pages represents the number of pages in a fragment. The page_count column tells you how many pages are in a particular index level. From my result set above, you see the the remaining columns all have NULL values. This is because I did not specify a ‘mode’ in my query and as a result it used the ‘LIMITED’ mode by default. The LIMITED mode is meant to be lightweight so it does collect information for every column in the result set. I will re-run my query again using the ‘DETAILED’ mode and you will see we now have results for these rows. SELECT * FROM sys.dm_db_index_physical_stats(db_id('AdventureWorks2012'), NULL, NULL, NULL, ‘DETAILED’)   From the remaining columns, you see we get even more detailed information such as how many records are in a particular index level (record_count). We have a column for ghost_record_count which represents the number of records that have been marked for deletion, but have not physically been removed by the background ghost cleanup process. We later see information on the MIN, MAX, and AVG record size in bytes. The forwarded_record_count column refers to records that have been updated and now no longer fit within the row on the page anymore and thus have to be moved. A forwarded record is left in the original location with a pointer to the new location. The last column in the result set is the compressed_page_count column which tells you how many pages in your index have been compressed. This is a very powerful DMF that returns good information about the current indexes in your system. However, based on the mode you select, it could be a very resource intensive function so be careful with how you use it. For more information on this Dynamic Management Function, please see the below Books Online link: http://msdn.microsoft.com/en-us/library/ms188917.aspx Follow me on Twitter @PrimeTimeDBA

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  • SharePoint 2010 Hosting :: SharePoint 2010 Custom Web Template

    - by mbridge
    SharePoint 2010 offers some changes and additions to the SharePoint 2007 approach. Site definitions and publishing providers remain largely the same, but site templates created from the SharePoint UI or SharePoint Designer are now saved to a .WSP file, the same solution deployment packaging file format used for deploying custom SharePoint solutions. Site Templates saved to a .WSP solution file can be imported into Visual Studio for additional customization. Introducing the WebTemplate Feature Element The WebTemplate element, introduced in SharePoint 2010, allows site templates to be defined and deployed as a Feature as part of a solution package. A WebTemplate element feature can be used to deploy site templates in either a Farm or Sandbox solution - without modification. If deployed as a Farm feature and solution, site templates will appear in the site collection provisioning page in Central Administration and can be used to provision new site collections, or within a Site Collection to create sub-sites. If deployed as a Site feature and Sandbox solution, site templates will appear within the site collection to support creating a root site or sub-sites. Creating a new WebTemplate Feature in Visual Studio 2010 In addition to supporting the ability to save and import Site Templates created from the SharePoint UI into Visual Studio for customization, it can also be used to create new site templates from scratch. In the following sample we will walk through how to create a new WebTemplate solution based on  a customized version of the out-of-box Blank Site. 1. Create a new Empty SharePoint Project in Visual Studio 2010. 2. Add a new Empty Element to the project. we like to create folders for each type of element in our solution, so in our sample, we have created a Web Templates folder, and then added the BLANKENT element. NOTE: The Elements folder MUST share the same name as the WebTemplate name property. 3. Open the empty Elements.xml and add the <WebTemplate /> element block. 4. Copy the default.aspx and ONET.XML files from the STS site definition location at 14\TEMPLATES\Site Templates\STS. We will customize the ONET.XML in the next section. Open the properties for each file and set the Deployment Type to ElementFile. This ensures the files are deployed with the Element when included in a Feature. 5. By default a new feature is added to the solution for you automatically when a new element is added to the solution. Rename and edit the feature as appropriate. Select Farm for the scope to deploy the WebTemplate to the entire farm, or Site for a sandboxed solution. Customize the ONET.XML At this point, you have a working WebTemplate solution that will deploy the identical site to the out-of-box Blank Site, however the ONET.XML supporting the STS site definition contains 3 configurations – essentially 3 separate site templates and can be simplified before customizing. In the following sample, we have trimmed the ONET.XML to the essentials for a single Site Template, and added references to the <SiteFeatures /> and <WebFeatures /> elements to include the SharePoint Standard and Enterprise features. We have left the top-level navigation bar, and the default page module intact, but removed all other extraneous markup.

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  • Editor's Notebook - Social Aura: Insights from the Oracle Social Media Summit

    - by user462779
    Panelists talk social marketing at the Oracle Social Media Summit On November 14, I traveled to Las Vegas for the first-ever Oracle Social Media Summit. The two day event featured an impressive collection of social media luminaries including: David Kirkpatrick (founder and CEO of Techonomy Media and author of The Facebook Effect), John Yi (Head of Marketing Partnerships, Facebook), Matt Dickman (EVP of Social Business Innovation, Weber Shandwick), and Lyndsay Iorio (Social Media & Communications Manager, NBC Sports Group) among others. It was also a great opportunity to talk shop with some of our new Vitrue and Involver colleagues who have been returning great social media results even before their companies were acquired by Oracle. I was live tweeting the event from @OracleProfit which was great for those who wanted to follow along with the proceedings from the comfort of their office or blackjack table. But I've also found over the years that live tweeting an event is a handy way to take notes: I can sift back through my record of what people said or thoughts I had at the time and organize the Twitter messages into some kind of summary account of the proceedings. I've had nearly a month to reflect on the presentations and conversations at the event and a few key topics have emerged: David Kirkpatrick's comment during the opening presentation really set the stage for the conversations that followed. Especially if you are a marketer or publisher, the idea that you are in a one-way broadcast relationship with your audience is a thing of the past. "Rising above the noise" does not mean reaching for a megaphone, ALL CAPS, or exclamation marks. Hype will not motivate social media denizens to do anything but unfollow and tune you out. But knowing your audience, creating quality content and/or offers for them, treating them with respect, and making an authentic effort to please them: that's what I believe is now necessary. And Kirkpatrick's comment early in the day really made the point. Later in the day, our friends @Vitrue demonstrated this point by elaborating on a comment by Facebook's John Yi. If a social strategy is comprised of nothing more than cutting/pasting the same message into different social media properties, you're missing the opportunity to have an actual conversation. That's not shouting at your audience, but it does feel like an empty gesture. Walter Benjamin, perplexed by auraless Twitter messages Not to get too far afield, but 20th century cultural critic Walter Benjamin has a concept that is useful for understanding the dynamics of the empty social media gesture: Aura. In his work The Work of Art in the Age of Mechanical Reproduction, Benjamin struggled to understand the difference he percieved between the value of a hand-made art object (a painting, wood cutting, sculpture, etc.) and a photograph. For Benjamin, aura is similar to the "soul" of an artwork--the intangible essence that is created when an artist picks up a tool and puts creative energy and effort into a work. I'll defer to Wikipedia: "He argues that the "sphere of authenticity is outside the technical" so that the original artwork is independent of the copy, yet through the act of reproduction something is taken from the original by changing its context. He also introduces the idea of the "aura" of a work and its absence in a reproduction." So make sure you put aura into your social interactions. Don't just mechanically reproduce them. Keeping aura in your interactions requires the intervention of an actual human being. That's why @NoahHorton's comment about content curation struck me as incredibly important. Maybe it's just my own prejudice, being in the content curation business myself. And it's not to totally discount machine-aided content management systems, content recommendation engines, and other tech-driven tools for building an exceptional content experience. It's just that without that human interaction--that editor who reviews the analytics and responds to user feedback--interactions over social media feel a bit empty. It is SOCIAL media, right? (We'll leave the conversation about social machines for another day). At the end of the day, experimentation is key. Just like trying to find that right joke to tell at the beginning of your presentation or that good opening like at a cocktail party, social media messages and interactions can take some trial and error. Don't be afraid to try things, tinker with incomplete ideas, abandon things that don't work, and engage in the conversation. And make sure your heart is in it, otherwise your audience can tell. And finally:

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  • SQL SERVER – Introduction to LEAD and LAG – Analytic Functions Introduced in SQL Server 2012

    - by pinaldave
    SQL Server 2012 introduces new analytical function LEAD() and LAG(). This functions accesses data from a subsequent row (for lead) and previous row (for lag) in the same result set without the use of a self-join . It will be very difficult to explain this in words so I will attempt small example to explain you this function. Instead of creating new table, I will be using AdventureWorks sample database as most of the developer uses that for experiment. Let us fun following query. USE AdventureWorks GO SELECT s.SalesOrderID,s.SalesOrderDetailID,s.OrderQty, LEAD(SalesOrderDetailID) OVER (ORDER BY SalesOrderDetailID ) LeadValue, LAG(SalesOrderDetailID) OVER (ORDER BY SalesOrderDetailID ) LagValue FROM Sales.SalesOrderDetail s WHERE SalesOrderID IN (43670, 43669, 43667, 43663) ORDER BY s.SalesOrderID,s.SalesOrderDetailID,s.OrderQty GO Above query will give us following result. When we look at above resultset it is very clear that LEAD function gives us value which is going to come in next line and LAG function gives us value which was encountered in previous line. If we have to generate the same result without using this function we will have to use self join. In future blog post we will see the same. Let us explore this function a bit more. This function not only provide previous or next line but it can also access any line before or after using offset. Let us fun following query, where LEAD and LAG function accesses the row with offset of 2. USE AdventureWorks GO SELECT s.SalesOrderID,s.SalesOrderDetailID,s.OrderQty, LEAD(SalesOrderDetailID,2) OVER (ORDER BY SalesOrderDetailID ) LeadValue, LAG(SalesOrderDetailID,2) OVER (ORDER BY SalesOrderDetailID ) LagValue FROM Sales.SalesOrderDetail s WHERE SalesOrderID IN (43670, 43669, 43667, 43663) ORDER BY s.SalesOrderID,s.SalesOrderDetailID,s.OrderQty GO Above query will give us following result. You can see the LEAD and LAG functions  now have interval of  rows when they are returning results. As there is interval of two rows the first two rows in LEAD function and last two rows in LAG function will return NULL value. You can easily replace this NULL Value with any other default value by passing third parameter in LEAD and LAG function. Let us fun following query. USE AdventureWorks GO SELECT s.SalesOrderID,s.SalesOrderDetailID,s.OrderQty, LEAD(SalesOrderDetailID,2,0) OVER (ORDER BY SalesOrderDetailID ) LeadValue, LAG(SalesOrderDetailID,2,0) OVER (ORDER BY SalesOrderDetailID ) LagValue FROM Sales.SalesOrderDetail s WHERE SalesOrderID IN (43670, 43669, 43667, 43663) ORDER BY s.SalesOrderID,s.SalesOrderDetailID,s.OrderQty GO Above query will give us following result, where NULL are now replaced with value 0. Just like any other analytic function we can easily partition this function as well. Let us see the use of PARTITION BY in this clause. USE AdventureWorks GO SELECT s.SalesOrderID,s.SalesOrderDetailID,s.OrderQty, LEAD(SalesOrderDetailID) OVER (PARTITION BY SalesOrderID ORDER BY SalesOrderDetailID ) LeadValue, LAG(SalesOrderDetailID) OVER (PARTITION BY SalesOrderID ORDER BY SalesOrderDetailID ) LagValue FROM Sales.SalesOrderDetail s WHERE SalesOrderID IN (43670, 43669, 43667, 43663) ORDER BY s.SalesOrderID,s.SalesOrderDetailID,s.OrderQty GO Above query will give us following result, where now the data is partitioned by SalesOrderID and LEAD and LAG functions are returning the appropriate result in that window. As now there are smaller partition in my query, you will see higher presence of NULL. In future blog post we will see how this functions are compared to SELF JOIN. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Function, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • perl comparing 2 data file as array 2D for finding match one to one [migrated]

    - by roman serpa
    I'm doing a program that uses combinations of variables ( combiData.txt 63 rows x different number of columns) for analysing a data table ( j1j2_1.csv, 1000filas x 19 columns ) , to choose how many times each combination is repeated in data table and which rows come from (for instance, tableData[row][4]). I have tried to compile it , however I get the following message : Use of uninitialized value $val in numeric eq (==) at rowInData.pl line 34. Use of reference "ARRAY(0x1a2eae4)" as array index at rowInData.pl line 56. Use of reference "ARRAY(0x1a1334c)" as array index at rowInData.pl line 56. Use of uninitialized value in subtraction (-) at rowInData.pl line 56. Modification of non-creatable array value attempted, subscript -1 at rowInData.pl line 56. nothing This is my code: #!/usr/bin/perl use strict; use warnings; my $line_match; my $countTrue; open (FILE1, "<combiData.txt") or die "can't open file text1.txt\n"; my @tableCombi; while(<FILE1>) { my @row = split(' ', $_); push(@tableCombi, \@row); } close FILE1 || die $!; open (FILE2, "<j1j2_1.csv") or die "can't open file text1.txt\n"; my @tableData; while(<FILE2>) { my @row2 = split(/\s*,\s*/, $_); push(@tableData, \@row2); } close FILE2 || die $!; #function transform combiData.txt variable (position ) to the real value that i have to find in the data table. sub trueVal($){ my ($val) = $_[0]; if($val == 7){ return ('nonsynonymous_SNV'); } elsif( $val == 14) { return '1'; } elsif( $val == 15) { return '1';} elsif( $val == 16) { return '1'; } elsif( $val == 17) { return '1'; } elsif( $val == 18) { return '1';} elsif( $val == 19) { return '1';} else { print 'nothing'; } } #function IntToStr ( ) , i'm not sure if it is necessary) that transforms $ to strings , to use the function <eq> in the third loop for the array of combinations compared with the data array . sub IntToStr { return "$_[0]"; } for my $combi (@tableCombi) { $line_match = 0; for my $sheetData (@tableData) { $countTrue=0; for my $cell ( @$combi) { #my $temp =\$tableCombi[$combi][$cell] ; #if ( trueVal($tableCombi[$combi][$cell] ) eq $tableData[$sheetData][ $tableCombi[$combi][$cell] - 1 ] ){ #if ( IntToStr(trueVal($$temp )) eq IntToStr( $tableData[$sheetData][ $$temp-1] ) ){ if ( IntToStr(trueVal($tableCombi[$combi][$cell]) ) eq IntToStr($tableData[$sheetData][ $tableCombi[$combi][$cell] -1]) ){ $countTrue++;} if ($countTrue==@$combi){ $line_match++; #if ($line_match < 50){ print $tableData[$sheetData][4]." "; #} } } } print $line_match." \n"; }

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  • Is there a theory for "transactional" sequences of failing and no-fail actions?

    - by Ross Bencina
    My question is about writing transaction-like functions that execute sequences of actions, some of which may fail. It is related to the general C++ principle "destructors can't throw," no-fail property, and maybe also with multi-phase transactions or exception safety. However, I'm thinking about it in language-neutral terms. My concern is with correctly designing error handling in C++ functions that must be reliable. I would like to know what the concepts below are called so that I can learn more about them. I'm sorry that I can't ask the question more directly. Since I don't know this area I have provided an example to explain my question. The question is at the end. Here goes: Consider a sequence of steps or actions executed sequentially, where actions belong to one of two classes: those that always succeed, and those that may fail. In the examples below: S stands for an action that always succeeds (called "no-fail" in some settings). F stands for an action that may fail (for example, it might fail to allocate memory or do I/O that could fail). Consider a sequences of actions (executed sequentially from left to right): S->S->S->S Since each action in the sequence above succeeds, the whole sequence succeeds. On the other hand, the following sequence may fail because the last action may fail: S->S->S->F So, claim: a sequence has the no-fail (S) property if and only if all of its actions are no-fail. Now, I'm interested in action sequences that form "atomic transactions", with "failure atomicity," i.e. where either the whole sequence completes successfully, or there is no effect. I.e. if some action fails, the earlier ones must be rolled back. This requires that any successfully executed actions prior to a failing action must always be able to be rolled back. Consider the sequence: S->S->S->F S<-S<-S In the example above, the first row is the forward path of the transaction, and the second row are inverse actions (executed from right to left) that can be used to roll back if the final top row actions fails. It seems to me that for a transaction to support failure atomicity, the following invariant must hold: Claim: To support failure atomicity (either completion or complete roll-back on failure) all actions preceding the latest failable (F) action on the forward path (marked * in the example below) must have no-fail (S) inverses. The following is an example of a sequence that supports failure atomicity: * S->F->F->F S<-S<-S Further, if we want the transaction to be able to attempt cancellation mid-way through, but still guarantee either full completion or full rollback then we need the following property: Claim: To support failure atomicity and cancellation mid-way through execution, in the face of errors in the inverse (cancellation) path, all actions following the earliest failable (F) inverse on the reverse path (marked *) must be no-fail (S). F->F->F->S->S S<-S<-F<-F * I believe that these two conditions guarantee that an abortable/cancelable transaction will never get "stuck". My questions are: What is the study and theory of these properties called? are my claims correct? and what else is there to know? UPDATE 1: Updated terminology: what I previously called "robustness" is called atomicity in the database literature. UPDATE 2: Added explicit reference to failure atomicity, which seems to be a thing.

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  • Styling specific columns and rows

    - by hattenn
    I'm trying to style some specific parts of a 5x4 table that I create. It should be like this: Every even numbered row and every odd numbered row should get a different color. Text in the second, third, and fourth columns should be centered. I have this table: <table> <caption>Some caption</caption> <colgroup> <col> <col class="value"> <col class="value"> <col class="value"> </colgroup> <thead> <tr> <th id="year">Year</th> <th>1999</th> <th>2000</th> <th>2001</th> </tr> </thead> <tbody> <tr class="oddLine"> <td>Berlin</td> <td>3,3</td> <td>1,9</td> <td>2,3</td> </tr> <tr class="evenLine"> <td>Hamburg</td> <td>1,5</td> <td>1,3</td> <td>2,0</td> </tr> <tr class="oddLine"> <td>München</td> <td>0,6</td> <td>1,1</td> <td>1,0</td> </tr> <tr class="evenLine"> <td>Frankfurt</td> <td>1,3</td> <td>1,6</td> <td>1,9</td> </tr> </tbody> <tfoot> <tr class="oddLine"> <td>Total</td> <td>6,7</td> <td>5,9</td> <td>7,2</td> </tr> </tfoot> </table> And I have this CSS file: table, th, td { border: 1px solid black; border-collapse: collapse; padding: 0px 5px; } #year { text-align: left; } .oddLine { background-color: #DDDDDD; } .evenLine { background-color: #BBBBBB; } .value { text-align: center; } And this doesn't work. The text in the columns are not centered. What is the problem here? And is there a way to solve it (other than changing the class of all the cells that I want centered)? P.S.: I think there's some interference with .evenLine and .oddLine classes. Because when I put "background: black" in the class "value", it changes the background color of the columns in the first row. The thing is, if I delete those two classes, text-align still doesn't work, but background attribute works perfectly. Argh...

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  • A Taxonomy of Numerical Methods v1

    - by JoshReuben
    Numerical Analysis – When, What, (but not how) Once you understand the Math & know C++, Numerical Methods are basically blocks of iterative & conditional math code. I found the real trick was seeing the forest for the trees – knowing which method to use for which situation. Its pretty easy to get lost in the details – so I’ve tried to organize these methods in a way that I can quickly look this up. I’ve included links to detailed explanations and to C++ code examples. I’ve tried to classify Numerical methods in the following broad categories: Solving Systems of Linear Equations Solving Non-Linear Equations Iteratively Interpolation Curve Fitting Optimization Numerical Differentiation & Integration Solving ODEs Boundary Problems Solving EigenValue problems Enjoy – I did ! Solving Systems of Linear Equations Overview Solve sets of algebraic equations with x unknowns The set is commonly in matrix form Gauss-Jordan Elimination http://en.wikipedia.org/wiki/Gauss%E2%80%93Jordan_elimination C++: http://www.codekeep.net/snippets/623f1923-e03c-4636-8c92-c9dc7aa0d3c0.aspx Produces solution of the equations & the coefficient matrix Efficient, stable 2 steps: · Forward Elimination – matrix decomposition: reduce set to triangular form (0s below the diagonal) or row echelon form. If degenerate, then there is no solution · Backward Elimination –write the original matrix as the product of ints inverse matrix & its reduced row-echelon matrix à reduce set to row canonical form & use back-substitution to find the solution to the set Elementary ops for matrix decomposition: · Row multiplication · Row switching · Add multiples of rows to other rows Use pivoting to ensure rows are ordered for achieving triangular form LU Decomposition http://en.wikipedia.org/wiki/LU_decomposition C++: http://ganeshtiwaridotcomdotnp.blogspot.co.il/2009/12/c-c-code-lu-decomposition-for-solving.html Represent the matrix as a product of lower & upper triangular matrices A modified version of GJ Elimination Advantage – can easily apply forward & backward elimination to solve triangular matrices Techniques: · Doolittle Method – sets the L matrix diagonal to unity · Crout Method - sets the U matrix diagonal to unity Note: both the L & U matrices share the same unity diagonal & can be stored compactly in the same matrix Gauss-Seidel Iteration http://en.wikipedia.org/wiki/Gauss%E2%80%93Seidel_method C++: http://www.nr.com/forum/showthread.php?t=722 Transform the linear set of equations into a single equation & then use numerical integration (as integration formulas have Sums, it is implemented iteratively). an optimization of Gauss-Jacobi: 1.5 times faster, requires 0.25 iterations to achieve the same tolerance Solving Non-Linear Equations Iteratively find roots of polynomials – there may be 0, 1 or n solutions for an n order polynomial use iterative techniques Iterative methods · used when there are no known analytical techniques · Requires set functions to be continuous & differentiable · Requires an initial seed value – choice is critical to convergence à conduct multiple runs with different starting points & then select best result · Systematic - iterate until diminishing returns, tolerance or max iteration conditions are met · bracketing techniques will always yield convergent solutions, non-bracketing methods may fail to converge Incremental method if a nonlinear function has opposite signs at 2 ends of a small interval x1 & x2, then there is likely to be a solution in their interval – solutions are detected by evaluating a function over interval steps, for a change in sign, adjusting the step size dynamically. Limitations – can miss closely spaced solutions in large intervals, cannot detect degenerate (coinciding) solutions, limited to functions that cross the x-axis, gives false positives for singularities Fixed point method http://en.wikipedia.org/wiki/Fixed-point_iteration C++: http://books.google.co.il/books?id=weYj75E_t6MC&pg=PA79&lpg=PA79&dq=fixed+point+method++c%2B%2B&source=bl&ots=LQ-5P_taoC&sig=lENUUIYBK53tZtTwNfHLy5PEWDk&hl=en&sa=X&ei=wezDUPW1J5DptQaMsIHQCw&redir_esc=y#v=onepage&q=fixed%20point%20method%20%20c%2B%2B&f=false Algebraically rearrange a solution to isolate a variable then apply incremental method Bisection method http://en.wikipedia.org/wiki/Bisection_method C++: http://numericalcomputing.wordpress.com/category/algorithms/ Bracketed - Select an initial interval, keep bisecting it ad midpoint into sub-intervals and then apply incremental method on smaller & smaller intervals – zoom in Adv: unaffected by function gradient à reliable Disadv: slow convergence False Position Method http://en.wikipedia.org/wiki/False_position_method C++: http://www.dreamincode.net/forums/topic/126100-bisection-and-false-position-methods/ Bracketed - Select an initial interval , & use the relative value of function at interval end points to select next sub-intervals (estimate how far between the end points the solution might be & subdivide based on this) Newton-Raphson method http://en.wikipedia.org/wiki/Newton's_method C++: http://www-users.cselabs.umn.edu/classes/Summer-2012/csci1113/index.php?page=./newt3 Also known as Newton's method Convenient, efficient Not bracketed – only a single initial guess is required to start iteration – requires an analytical expression for the first derivative of the function as input. Evaluates the function & its derivative at each step. Can be extended to the Newton MutiRoot method for solving multiple roots Can be easily applied to an of n-coupled set of non-linear equations – conduct a Taylor Series expansion of a function, dropping terms of order n, rewrite as a Jacobian matrix of PDs & convert to simultaneous linear equations !!! Secant Method http://en.wikipedia.org/wiki/Secant_method C++: http://forum.vcoderz.com/showthread.php?p=205230 Unlike N-R, can estimate first derivative from an initial interval (does not require root to be bracketed) instead of inputting it Since derivative is approximated, may converge slower. Is fast in practice as it does not have to evaluate the derivative at each step. Similar implementation to False Positive method Birge-Vieta Method http://mat.iitm.ac.in/home/sryedida/public_html/caimna/transcendental/polynomial%20methods/bv%20method.html C++: http://books.google.co.il/books?id=cL1boM2uyQwC&pg=SA3-PA51&lpg=SA3-PA51&dq=Birge-Vieta+Method+c%2B%2B&source=bl&ots=QZmnDTK3rC&sig=BPNcHHbpR_DKVoZXrLi4nVXD-gg&hl=en&sa=X&ei=R-_DUK2iNIjzsgbE5ID4Dg&redir_esc=y#v=onepage&q=Birge-Vieta%20Method%20c%2B%2B&f=false combines Horner's method of polynomial evaluation (transforming into lesser degree polynomials that are more computationally efficient to process) with Newton-Raphson to provide a computational speed-up Interpolation Overview Construct new data points for as close as possible fit within range of a discrete set of known points (that were obtained via sampling, experimentation) Use Taylor Series Expansion of a function f(x) around a specific value for x Linear Interpolation http://en.wikipedia.org/wiki/Linear_interpolation C++: http://www.hamaluik.com/?p=289 Straight line between 2 points à concatenate interpolants between each pair of data points Bilinear Interpolation http://en.wikipedia.org/wiki/Bilinear_interpolation C++: http://supercomputingblog.com/graphics/coding-bilinear-interpolation/2/ Extension of the linear function for interpolating functions of 2 variables – perform linear interpolation first in 1 direction, then in another. Used in image processing – e.g. texture mapping filter. Uses 4 vertices to interpolate a value within a unit cell. Lagrange Interpolation http://en.wikipedia.org/wiki/Lagrange_polynomial C++: http://www.codecogs.com/code/maths/approximation/interpolation/lagrange.php For polynomials Requires recomputation for all terms for each distinct x value – can only be applied for small number of nodes Numerically unstable Barycentric Interpolation http://epubs.siam.org/doi/pdf/10.1137/S0036144502417715 C++: http://www.gamedev.net/topic/621445-barycentric-coordinates-c-code-check/ Rearrange the terms in the equation of the Legrange interpolation by defining weight functions that are independent of the interpolated value of x Newton Divided Difference Interpolation http://en.wikipedia.org/wiki/Newton_polynomial C++: http://jee-appy.blogspot.co.il/2011/12/newton-divided-difference-interpolation.html Hermite Divided Differences: Interpolation polynomial approximation for a given set of data points in the NR form - divided differences are used to approximately calculate the various differences. For a given set of 3 data points , fit a quadratic interpolant through the data Bracketed functions allow Newton divided differences to be calculated recursively Difference table Cubic Spline Interpolation http://en.wikipedia.org/wiki/Spline_interpolation C++: https://www.marcusbannerman.co.uk/index.php/home/latestarticles/42-articles/96-cubic-spline-class.html Spline is a piecewise polynomial Provides smoothness – for interpolations with significantly varying data Use weighted coefficients to bend the function to be smooth & its 1st & 2nd derivatives are continuous through the edge points in the interval Curve Fitting A generalization of interpolating whereby given data points may contain noise à the curve does not necessarily pass through all the points Least Squares Fit http://en.wikipedia.org/wiki/Least_squares C++: http://www.ccas.ru/mmes/educat/lab04k/02/least-squares.c Residual – difference between observed value & expected value Model function is often chosen as a linear combination of the specified functions Determines: A) The model instance in which the sum of squared residuals has the least value B) param values for which model best fits data Straight Line Fit Linear correlation between independent variable and dependent variable Linear Regression http://en.wikipedia.org/wiki/Linear_regression C++: http://www.oocities.org/david_swaim/cpp/linregc.htm Special case of statistically exact extrapolation Leverage least squares Given a basis function, the sum of the residuals is determined and the corresponding gradient equation is expressed as a set of normal linear equations in matrix form that can be solved (e.g. using LU Decomposition) Can be weighted - Drop the assumption that all errors have the same significance –-> confidence of accuracy is different for each data point. Fit the function closer to points with higher weights Polynomial Fit - use a polynomial basis function Moving Average http://en.wikipedia.org/wiki/Moving_average C++: http://www.codeproject.com/Articles/17860/A-Simple-Moving-Average-Algorithm Used for smoothing (cancel fluctuations to highlight longer-term trends & cycles), time series data analysis, signal processing filters Replace each data point with average of neighbors. Can be simple (SMA), weighted (WMA), exponential (EMA). Lags behind latest data points – extra weight can be given to more recent data points. Weights can decrease arithmetically or exponentially according to distance from point. Parameters: smoothing factor, period, weight basis Optimization Overview Given function with multiple variables, find Min (or max by minimizing –f(x)) Iterative approach Efficient, but not necessarily reliable Conditions: noisy data, constraints, non-linear models Detection via sign of first derivative - Derivative of saddle points will be 0 Local minima Bisection method Similar method for finding a root for a non-linear equation Start with an interval that contains a minimum Golden Search method http://en.wikipedia.org/wiki/Golden_section_search C++: http://www.codecogs.com/code/maths/optimization/golden.php Bisect intervals according to golden ratio 0.618.. Achieves reduction by evaluating a single function instead of 2 Newton-Raphson Method Brent method http://en.wikipedia.org/wiki/Brent's_method C++: http://people.sc.fsu.edu/~jburkardt/cpp_src/brent/brent.cpp Based on quadratic or parabolic interpolation – if the function is smooth & parabolic near to the minimum, then a parabola fitted through any 3 points should approximate the minima – fails when the 3 points are collinear , in which case the denominator is 0 Simplex Method http://en.wikipedia.org/wiki/Simplex_algorithm C++: http://www.codeguru.com/cpp/article.php/c17505/Simplex-Optimization-Algorithm-and-Implemetation-in-C-Programming.htm Find the global minima of any multi-variable function Direct search – no derivatives required At each step it maintains a non-degenerative simplex – a convex hull of n+1 vertices. Obtains the minimum for a function with n variables by evaluating the function at n-1 points, iteratively replacing the point of worst result with the point of best result, shrinking the multidimensional simplex around the best point. Point replacement involves expanding & contracting the simplex near the worst value point to determine a better replacement point Oscillation can be avoided by choosing the 2nd worst result Restart if it gets stuck Parameters: contraction & expansion factors Simulated Annealing http://en.wikipedia.org/wiki/Simulated_annealing C++: http://code.google.com/p/cppsimulatedannealing/ Analogy to heating & cooling metal to strengthen its structure Stochastic method – apply random permutation search for global minima - Avoid entrapment in local minima via hill climbing Heating schedule - Annealing schedule params: temperature, iterations at each temp, temperature delta Cooling schedule – can be linear, step-wise or exponential Differential Evolution http://en.wikipedia.org/wiki/Differential_evolution C++: http://www.amichel.com/de/doc/html/ More advanced stochastic methods analogous to biological processes: Genetic algorithms, evolution strategies Parallel direct search method against multiple discrete or continuous variables Initial population of variable vectors chosen randomly – if weighted difference vector of 2 vectors yields a lower objective function value then it replaces the comparison vector Many params: #parents, #variables, step size, crossover constant etc Convergence is slow – many more function evaluations than simulated annealing Numerical Differentiation Overview 2 approaches to finite difference methods: · A) approximate function via polynomial interpolation then differentiate · B) Taylor series approximation – additionally provides error estimate Finite Difference methods http://en.wikipedia.org/wiki/Finite_difference_method C++: http://www.wpi.edu/Pubs/ETD/Available/etd-051807-164436/unrestricted/EAMPADU.pdf Find differences between high order derivative values - Approximate differential equations by finite differences at evenly spaced data points Based on forward & backward Taylor series expansion of f(x) about x plus or minus multiples of delta h. Forward / backward difference - the sums of the series contains even derivatives and the difference of the series contains odd derivatives – coupled equations that can be solved. Provide an approximation of the derivative within a O(h^2) accuracy There is also central difference & extended central difference which has a O(h^4) accuracy Richardson Extrapolation http://en.wikipedia.org/wiki/Richardson_extrapolation C++: http://mathscoding.blogspot.co.il/2012/02/introduction-richardson-extrapolation.html A sequence acceleration method applied to finite differences Fast convergence, high accuracy O(h^4) Derivatives via Interpolation Cannot apply Finite Difference method to discrete data points at uneven intervals – so need to approximate the derivative of f(x) using the derivative of the interpolant via 3 point Lagrange Interpolation Note: the higher the order of the derivative, the lower the approximation precision Numerical Integration Estimate finite & infinite integrals of functions More accurate procedure than numerical differentiation Use when it is not possible to obtain an integral of a function analytically or when the function is not given, only the data points are Newton Cotes Methods http://en.wikipedia.org/wiki/Newton%E2%80%93Cotes_formulas C++: http://www.siafoo.net/snippet/324 For equally spaced data points Computationally easy – based on local interpolation of n rectangular strip areas that is piecewise fitted to a polynomial to get the sum total area Evaluate the integrand at n+1 evenly spaced points – approximate definite integral by Sum Weights are derived from Lagrange Basis polynomials Leverage Trapezoidal Rule for default 2nd formulas, Simpson 1/3 Rule for substituting 3 point formulas, Simpson 3/8 Rule for 4 point formulas. For 4 point formulas use Bodes Rule. Higher orders obtain more accurate results Trapezoidal Rule uses simple area, Simpsons Rule replaces the integrand f(x) with a quadratic polynomial p(x) that uses the same values as f(x) for its end points, but adds a midpoint Romberg Integration http://en.wikipedia.org/wiki/Romberg's_method C++: http://code.google.com/p/romberg-integration/downloads/detail?name=romberg.cpp&can=2&q= Combines trapezoidal rule with Richardson Extrapolation Evaluates the integrand at equally spaced points The integrand must have continuous derivatives Each R(n,m) extrapolation uses a higher order integrand polynomial replacement rule (zeroth starts with trapezoidal) à a lower triangular matrix set of equation coefficients where the bottom right term has the most accurate approximation. The process continues until the difference between 2 successive diagonal terms becomes sufficiently small. Gaussian Quadrature http://en.wikipedia.org/wiki/Gaussian_quadrature C++: http://www.alglib.net/integration/gaussianquadratures.php Data points are chosen to yield best possible accuracy – requires fewer evaluations Ability to handle singularities, functions that are difficult to evaluate The integrand can include a weighting function determined by a set of orthogonal polynomials. Points & weights are selected so that the integrand yields the exact integral if f(x) is a polynomial of degree <= 2n+1 Techniques (basically different weighting functions): · Gauss-Legendre Integration w(x)=1 · Gauss-Laguerre Integration w(x)=e^-x · Gauss-Hermite Integration w(x)=e^-x^2 · Gauss-Chebyshev Integration w(x)= 1 / Sqrt(1-x^2) Solving ODEs Use when high order differential equations cannot be solved analytically Evaluated under boundary conditions RK for systems – a high order differential equation can always be transformed into a coupled first order system of equations Euler method http://en.wikipedia.org/wiki/Euler_method C++: http://rosettacode.org/wiki/Euler_method First order Runge–Kutta method. Simple recursive method – given an initial value, calculate derivative deltas. Unstable & not very accurate (O(h) error) – not used in practice A first-order method - the local error (truncation error per step) is proportional to the square of the step size, and the global error (error at a given time) is proportional to the step size In evolving solution between data points xn & xn+1, only evaluates derivatives at beginning of interval xn à asymmetric at boundaries Higher order Runge Kutta http://en.wikipedia.org/wiki/Runge%E2%80%93Kutta_methods C++: http://www.dreamincode.net/code/snippet1441.htm 2nd & 4th order RK - Introduces parameterized midpoints for more symmetric solutions à accuracy at higher computational cost Adaptive RK – RK-Fehlberg – estimate the truncation at each integration step & automatically adjust the step size to keep error within prescribed limits. At each step 2 approximations are compared – if in disagreement to a specific accuracy, the step size is reduced Boundary Value Problems Where solution of differential equations are located at 2 different values of the independent variable x à more difficult, because cannot just start at point of initial value – there may not be enough starting conditions available at the end points to produce a unique solution An n-order equation will require n boundary conditions – need to determine the missing n-1 conditions which cause the given conditions at the other boundary to be satisfied Shooting Method http://en.wikipedia.org/wiki/Shooting_method C++: http://ganeshtiwaridotcomdotnp.blogspot.co.il/2009/12/c-c-code-shooting-method-for-solving.html Iteratively guess the missing values for one end & integrate, then inspect the discrepancy with the boundary values of the other end to adjust the estimate Given the starting boundary values u1 & u2 which contain the root u, solve u given the false position method (solving the differential equation as an initial value problem via 4th order RK), then use u to solve the differential equations. Finite Difference Method For linear & non-linear systems Higher order derivatives require more computational steps – some combinations for boundary conditions may not work though Improve the accuracy by increasing the number of mesh points Solving EigenValue Problems An eigenvalue can substitute a matrix when doing matrix multiplication à convert matrix multiplication into a polynomial EigenValue For a given set of equations in matrix form, determine what are the solution eigenvalue & eigenvectors Similar Matrices - have same eigenvalues. Use orthogonal similarity transforms to reduce a matrix to diagonal form from which eigenvalue(s) & eigenvectors can be computed iteratively Jacobi method http://en.wikipedia.org/wiki/Jacobi_method C++: http://people.sc.fsu.edu/~jburkardt/classes/acs2_2008/openmp/jacobi/jacobi.html Robust but Computationally intense – use for small matrices < 10x10 Power Iteration http://en.wikipedia.org/wiki/Power_iteration For any given real symmetric matrix, generate the largest single eigenvalue & its eigenvectors Simplest method – does not compute matrix decomposition à suitable for large, sparse matrices Inverse Iteration Variation of power iteration method – generates the smallest eigenvalue from the inverse matrix Rayleigh Method http://en.wikipedia.org/wiki/Rayleigh's_method_of_dimensional_analysis Variation of power iteration method Rayleigh Quotient Method Variation of inverse iteration method Matrix Tri-diagonalization Method Use householder algorithm to reduce an NxN symmetric matrix to a tridiagonal real symmetric matrix vua N-2 orthogonal transforms     Whats Next Outside of Numerical Methods there are lots of different types of algorithms that I’ve learned over the decades: Data Mining – (I covered this briefly in a previous post: http://geekswithblogs.net/JoshReuben/archive/2007/12/31/ssas-dm-algorithms.aspx ) Search & Sort Routing Problem Solving Logical Theorem Proving Planning Probabilistic Reasoning Machine Learning Solvers (eg MIP) Bioinformatics (Sequence Alignment, Protein Folding) Quant Finance (I read Wilmott’s books – interesting) Sooner or later, I’ll cover the above topics as well.

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  • Reactive Extensions vs FileSystemWatcher

    - by Joel Mueller
    One of the things that has long bugged me about the FileSystemWatcher is the way it fires multiple events for a single logical change to a file. I know why it happens, but I don't want to have to care - I just want to reparse the file once, not 4-6 times in a row. Ideally, there would be an event that only fires when a given file is done changing, rather than every step along the way. Over the years I've come up with various solutions to this problem, of varying degrees of ugliness. I thought Reactive Extensions would be the ultimate solution, but there's something I'm not doing right, and I'm hoping someone can point out my mistake. I have an extension method: public static IObservable<IEvent<FileSystemEventArgs>> GetChanged(this FileSystemWatcher that) { return Observable.FromEvent<FileSystemEventArgs>(that, "Changed"); } Ultimately, I would like to get one event per filename, within a given time period - so that four events in a row with a single filename are reduced to one event, but I don't lose anything if multiple files are modified at the same time. BufferWithTime sounds like the ideal solution. var bufferedChange = watcher.GetChanged() .Select(e => e.EventArgs.FullPath) .BufferWithTime(TimeSpan.FromSeconds(1)) .Where(e => e.Count > 0) .Select(e => e.Distinct()); When I subscribe to this observable, a single change to a monitored file triggers my subscription method four times in a row, which rather defeats the purpose. If I remove the Distinct() call, I see that each of the four calls contains two identical events - so there is some buffering going on. Increasing the TimeSpan passed to BufferWithTime seems to have no effect - I went as high as 20 seconds without any change in behavior. This is my first foray into Rx, so I'm probably missing something obvious. Am I doing it wrong? Is there a better approach? Thanks for any suggestions...

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  • OpenXML SDK: Make Excel recalculate formula

    - by chiccodoro
    I update some cells of an Excel spreadsheet through the Microsoft Office OpenXML SDK 2.0. Changing the values makes all cells containing formula that depend on the changed cells invalid. However, due to the cached values Excel does not recalculate the formular, even if the user clicks on "Calculate now". What is the best way to invalidate all dependent cells of the whole workbook through the SDK? So far, I've found the following code snippet at http://cdonner.com/introduction-to-microsofts-open-xml-format-sdk-20-with-a-focus-on-excel-documents.htm: public static void ClearAllValuesInSheet (SpreadsheetDocument spreadSheet, string sheetName) { WorksheetPart worksheetPart = GetWorksheetPartByName(spreadSheet, sheetName); foreach (Row row in worksheetPart.Worksheet. GetFirstChild().Elements()) { foreach (Cell cell in row.Elements()) { if (cell.CellFormula != null && cell.CellValue != null) { cell.CellValue.Remove(); } } } worksheetPart.Worksheet.Save(); } Besides the fact that this snippet does not compile for me, it has two limitations: It only invalidates a single sheet, although other sheets might contain dependent formula It does not take into account any dependencies. I am looking for a way that is efficient (in particular, only invalidates cells that depend on a certain cell's value), and takes all sheets into account. Update: In the meantime I have managed to make the code compile & run, and to remove the cached values on all sheets of the workbook. (See answers.) Still I am interested in better/alternative solutions, in particular how to only delete cached values of the cells that actually depend on the updated cell.

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  • T-SQL: Compute Subtotals For A Range Of Rows

    - by John Dibling
    MSSQL 2008. I am trying to construct a SQL statement which returns the total of column B for all rows where column A is between 2 known ranges. The range is a sliding window, and should be recomputed as it might be using a loop. Here is an example of what I'm trying to do, much simplified from my actual problem. Suppose I have this data: table: Test Year Sales ----------- ----------- 2000 200 2001 200 2002 200 2003 200 2004 200 2005 200 2006 200 2007 200 2008 200 2009 200 2010 200 2011 200 2012 200 2013 200 2014 200 2015 200 2016 200 2017 200 2018 200 2019 200 I want to construct a query which returns 1 row for every decade in the above table, like this: Desired Results: DecadeEnd TotalSales --------- ---------- 2009 2000 2010 2000 Where the first row is all the sales for the years 2000-2009, the second for years 2010-2019. The DecadeEnd is a sliding window that moves forward by a set ammount for each row in the result set. To illustrate, here is one way I can accomplish this using a loop: declare @startYear int set @startYear = (select top(1) [Year] from Test order by [Year] asc) declare @endYear int set @endYear = (select top(1) [Year] from Test order by [Year] desc) select @startYear, @endYear create table DecadeSummary (DecadeEnd int, TtlSales int) declare @i int -- first decade ends 9 years after the first data point set @i = (@startYear + 9) while @i <= @endYear begin declare @ttlSalesThisDecade int set @ttlSalesThisDecade = (select SUM(Sales) from Test where(Year <= @i and Year >= (@i-9))) insert into DecadeSummary values(@i, @ttlSalesThisDecade) set @i = (@i + 9) end select * from DecadeSummary This returns the data I want: DecadeEnd TtlSales ----------- ----------- 2009 2000 2018 2000 But it is very inefficient. How can I construct such a query?

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  • Java: immutable Stack?

    - by HH
    I chose to use Stacks and Tables before knowing Collections has immutable empty things only for Set, Map and List. Because the size of table does not change after its init: Integer[] table = new Intger[0] I can use the zero-witdh table as an empty table. But I cannot use final or empty Stack to get immutable Stack: No immutability to Stack with Final import java.io.*; import java.util.*; public class TestStack{ public static void main(String[] args) { final Stack<Integer> test = new Stack<Integer>(); Stack<Integer> test2 = new Stack<Integer>(); test.push(37707); test2.push(80437707); //WHY is there not an error to remove an elment // from FINAL stack? System.out.println(test.pop()); System.out.println(test2.pop()); } } Java Api 5 for list interface shows that Stack is an implementing class for list and arraylist, here. The java.coccurrent pkg does not have any immutable Stack data structure. From Stack to some immutable data structure How to get immutable Stack data structure? Can I box it with list? Should I switch my current implementatios from stacks to Lists to get immutable? Which immutable data structure is Very fast with about similar exec time as Stack?

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  • WPF DataGrid ComboBox Column: Propagating Header Combobox throughout column...

    - by LostKaleb
    Hey there! Here's my question: I've got a Datagrid in WPF and I have a first column that is a DataGridComboBoxColumn. What I'd like to do is to have a header for that column also with a combobox: altering the header with propagate throughout the column. I can get this done visually, but when I submit the data, the list that is bound with the Datagrid does not carry the new combobox values. <dg:DataGridComboBoxColumn SelectedItemBinding="{Binding BIBStatus}" ItemsSource="{Binding Source={StaticResource typeStatus}}" Width="0.20*"> <dg:DataGridComboBoxColumn.HeaderTemplate> <DataTemplate> <StackPanel> <TextBlock Text="Built-In Bridge"/> <ComboBox SelectedItem="{Binding BIBStatus}" SelectionChanged="ComboBox_SelectionChanged" ItemsSource="{Binding Source={StaticResource typeStatus}}"/> </StackPanel> </DataTemplate> </dg:DataGridComboBoxColumn.HeaderTemplate> </dg:DataGridComboBoxColumn> In the ComboBox_SelectionChanged I have the following code: DataGridColumn comboCol = this.gridResults.Columns[0]; for (int i = 0; i < this.gridResults.Items.Count; i++) { ComboBox myCmBox = (comboCol.GetCellContent(this.gridResults.Items[i]) as ComboBox); myCmBox.SelectedValue = ((ComboBox)sender).SelectedValue; } When I submit the data, I submit the list that is DataContext to the Datagrid; if I change the value of the first column addressing a row at a time, i.e. clicking the cell with the combobox in each row, the values are propagated to the list in DataContext, however if I change the value of the first column by the header it does not. Can anyone tell me what I'm missing? I'm guessing it's the way I affect each row, but I've tried SelectedValue, SelectedItem and SelectedIndex... all to no avail. Thanks in advance...

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  • Getting data from UITableView

    - by Tejaswi Yerukalapudi
    Hi, I have a few custom UITableViewCells - http://img11.imageshack.us/i/customfacilitiescell.png/ which are added to this UIViewController - http://img189.imageshack.us/i/facilitycontroller.png/ Now, on clicking a button in the controller, I'd like to get the on/off status of all the UISwitches in the controller. Thanks, Teja Edit: I've made a few edits, but I still can't figure out how to do this. My program structure currently - A CustomCell.xib that looks like this - http://img11.imageshack.us/i/customfacilitiescell.png/ A CustomCellController that a subclass of UITableViewCell that has the IBOutlets for the labels and switches from above. Now I have a UIViewController<UITableViewDataSource, UITableViewDelegate> (Say, Screen1Controller) which looks like - http://img189.imageshack.us/i/facilitycontroller.png/ The tableviewcell is being created like this - - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *Id= @"CustomFacilitiesCell"; CustomFacilitiesCellController *cell = (CustomFacilitiesCellController *)[tableView dequeueReusableCellWithIdentifier:Id]; if(cell == nil) { NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"CustomFacilitiesCell" owner:self options:nil]; for (id oneObject in nib) { if([oneObject isKindOfClass:[CustomFacilitiesCellController class]]) cell = (CustomFacilitiesCellController *) oneObject; } } NSUInteger row = [indexPath row]; CustomFacilitiesCellController *rowData = (CustomFacilitiesCellController *)[self.facilities objectAtIndex:row]; cell.facname.text = rowData.facname.text; cell.FacID.text = rowData.FacID.text; cell.facSwitch = [(CustomFacilitiesCellController *)rowData facSwitch]; UISwitch *temp = cell.facSwitch; [(UISwitch *)[cell facSwitch] addTarget:self action:@selector(facSwitchOptionChanged:) forControlEvents:UIControlEventValueChanged]; cell.facSwitch.on = NO; //cell.facSwitch.enabled = FALSE; cell.accessoryType = UITableViewCellAccessoryNone; return cell; } - (IBAction) facSwitchOptionChanged:(id) sender { int i=0; } In particular, my problem is that the facSwitchOptionChanged() isn't getting called. Thanks again for the help, Teja.

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  • Is there more than one jQuery Autocomplete widget?

    - by Cheeso
    I thought there was only one - included in jQuery UI and documented here. I know there are third-party autocomplete widgets that plug-in to jQuery, like the one from devbridge. But I would describe that as an autocomplete widget for jQuery, rather than the jQuery autocomplete widget. But on Stackoverflow, I see questions asking about an autocomplete widget that does not use the syntax described in the jQuery UI documentation. For example: jquery.autocomplete.js - how does autocomplete work? Jquery AutoComplete Plugin calling Help with jquery autocomplete and json response The jQuery UI syntax looks like this: $("#input1").autocomplete({ source: function(req, responseFn) { ... }, select: function(value, data){ ... } }); Whereas some of those other questions hae a syntax like this: $("#city").autocomplete("CUList.asmx/GetCUList", { dataType: 'jsonp', parse: function(data) { var rows = new Array(); for(var i=0; i<data.length; i++){ rows[i] = { data:data[i], value:data[i].CUName, result:data[i].CUName }; } return rows; }, formatItem: function(row, i, n) { return row.CUName + ', ' + row.CUCity; }, max: 50 }); What's the explanation for the discrepancy? People ask about "jquery autocomplete" without specifying which one. With no direction, shouldn't I assume THE jquery UI autocomplete?

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  • WPF ListView SelectedItem is null

    - by ozczecho
    Hi All I have a Listview that has a checkbox as one of the columns. If I click anywhere but the actual checkbox the SelectedItem of the ListView is set to the current selected row, as expected. If, on the other hand I click onto the checkbox (without clicking on the row first) then the SelectedItem is null or the previously clicked row. Can anyone help me out.... Cheers <ListView Width="auto" SelectionMode="Single" x:Name="listBox" ItemsSource="{Binding MyData}" SelectedItem="{Binding Path=SelectedMyData}"> <ListView.View> <GridView> <GridViewColumn Header="Date" Width="120"> <GridViewColumn.CellTemplate> <DataTemplate> <ContentPresenter Style="{StaticResource DateTimeContent}" Content="{Binding MyDate}"/> </DataTemplate> </GridViewColumn.CellTemplate> </GridViewColumn> <GridViewColumn.CellTemplate> <DataTemplate> <CheckBox IsThreeState="False" Checked="OnChkChecked" Unchecked="OnChkChecked" IsChecked="{Binding IsCorrect}"></CheckBox> </DataTemplate> </GridViewColumn.CellTemplate> </GridViewColumn> </GridView> </ListView.View> </ListView>

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