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  • Foreign key not working in MySQL: Why can I INSERT a value that's not in the foreign column?

    - by stalepretzel
    I've created a table in MySQL: CREATE TABLE actions ( A_id int NOT NULL AUTO_INCREMENT, type ENUM('rate','report','submit','edit','delete') NOT NULL, Q_id int NOT NULL, U_id int NOT NULL, date DATE NOT NULL, time TIME NOT NULL, rate tinyint(1), PRIMARY KEY (A_id), CONSTRAINT fk_Question FOREIGN KEY (Q_id) REFERENCES questions(P_id), CONSTRAINT fk_User FOREIGN KEY (U_id) REFERENCES users(P_id)); This created the table I wanted just fine (although a "DESCRIBE actions;" command showed me that the foreign keys were keys of type MUL, and I'm not sure what this means). However, when I try to enter a Q_id or a U_id that does not exist in the questions or users tables, MySQL still allows these values. What did I do wrong? How can I prevent a table with a foreign key from accepting invalid data? If I add TYPE=InnoDB to the end, I get an error: ERROR 1005 (HY000): Can't create table './quotes/actions.frm' (errno: 150) Why might that happen? I'm told that it's important to enforce data integrity with functional foreign keys, but also that InnoDB should not be used with MySQL. What do you recommend?

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  • With this generics code why am I getting "Argument 1: cannot convert from 'ToplogyLibrary.Relationsh

    - by Greg
    Hi, Any see why I'm getting a "Argument 1: cannot convert from 'ToplogyLibrary.RelationshipBase' to 'TRelationship'" in the code below, in CreateRelationship() ? public class TopologyBase<TKey, TNode, TRelationship> where TNode : NodeBase<TKey>, new() where TRelationship : RelationshipBase<TKey>, new() { // Properties public Dictionary<TKey, TNode> Nodes { get; private set; } public List<TRelationship> Relationships { get; private set; } // Constructors protected TopologyBase() { Nodes = new Dictionary<TKey, TNode>(); Relationships = new List<TRelationship>(); } // Methods public TNode CreateNode(TKey key) { var node = new TNode {Key = key}; Nodes.Add(node.Key, node); return node; } public void CreateRelationship(TNode parent, TNode child) { // Validation if (!Nodes.ContainsKey(parent.Key) || !Nodes.ContainsKey(child.Key)) { throw new ApplicationException("Can not create relationship as either parent or child was not in the graph: Parent:" + parent.Key + ", Child:" + child.Key); } // Add Relationship var r = new RelationshipBase<TNode>(); r.Parent = parent; r.Child = child; Relationships.Add(r); // *** HERE *** "Argument 1: cannot convert from 'ToplogyLibrary.RelationshipBase<TNode>' to 'TRelationship'" } } public class RelationshipBase<TNode> { public TNode Parent { get; set; } public TNode Child { get; set; } } public class NodeBase<T> { public T Key { get; set; } public NodeBase() { } public NodeBase(T key) { Key = key; } }

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  • Creating an application that can open files of a given format

    - by Brian Postow
    I've got an app, written in Obj-C. The info.plist has a list of file types that the app can open. I'm pretty sure that this is working because when I try to drag a file of an unacceptable type, the app doesn't highlight, but when I drag a file of an acceptable type, it does highlight, and lets me drop. When I drop, the app starts up, correctly, however, then I get a dialog saying: The document "foo.tiff" could not be opened. DocView cannot open files in the "TIFF File" format. I DO have this in my info.plist <key>CFBundleTypeExtensions</key> <array> <string>tif</string> <string>tiff</string> </array> <key>CFBundleTypeIconFile</key> <string>TIFFFile.icns</string> <key>CFBundleTypeName</key> <string>TIFF File</string> <key>CFBundleTypeOSTypes</key> <array> <string>TIFF</string> </array> <key>CFBundleTypeRole</key> <string>Viewer</string> <key>LSHandlerRank</key> <string>Documents/</string> Thanks.

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  • How can I stop Chromium from putting focus in the address bar when using the up arrow key to scroll

    - by codeLes
    This is bugging me. I'm at a web page, any web page, and I am scrolling back to the top of the page with the up arrow key as I tend to do when browsing a page and once I get to the top of the page if I don't pay attention and hit the key one more times than is needed Chromium in all it's wisdom decides I must want to do something with the address so it places the focus in the address bar. ARGH! Any way to stop this? I'm running Ubuntu 9.04 Jaunty and have installed the nightly build version of Chromium PPA.

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  • How to swap ctrl and fn key on a MacBook Pro running Windows 7 via Boot Camp?

    - by hobbes3
    There are sooooo many discussion on the internet about swapping the fn and ctrl key on a MacBook Pro. On the Mac side, a new software called ReMap4MacBook does a perfect job swapping the two key. But on the PC side (specifically Windows 7), I can't really find a definitive answer. Most post refer to this article but I read the loooong article and followed the instructions to no avail. I remember there used to be a program (maybe it was on XP) that not only swapped the two keys but it also controlled the fans on the MacBook Pro. But I can't remember the name and I also recall that that program stopped being updated like years ago. EDIT: It's called Input Remapper. So I am hoping there exist a simple program that I can simply run to swap those two keys.

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  • How can I run Ghost from a bootable USB key drive?

    - by Joe Philllips
    I have a laptop that does not have a cd-rom or floppy drive. It is able to boot from USB though. I have a disk image (ghost) of the disk that I need to restore back onto the laptop. I can't find a way to actually run the Ghost utility from a USB key though. I believe the ghost.exe should run from within DOS just fine but I can't seem to create a bootable USB key with DOS on it that allows me to run an EXE. Edit: I managed to find a Ghost utility that I could load from a bootable USB drive. Unfortunately, when I plug in my NTFS external drive (USB), it is not detected.

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  • cygWin connect by SSH using RSA key; ssh.exe couldn't create /home/user/.ssh

    - by Kirzilla
    I'm using Win XP and I'm trying to connect by SSH to remote host using RSA key. I've investigated that cygWin recognizes Documents and Settings dir as home directory Z:\app\cwRsync\bin>cygpath -H /cygdrive/c/Documents and Settings I've created .ssh directory in Documents and Settings/user/.ssh and moved known_hosts, id_rsa, id_rsa.pub there. Now, I'm trying to connect via ssh.exe to remote host Z:\app\cwRsync\bin>ssh -p 22 [email protected] Could not create directory '/home/user/.ssh'. The authenticity of host '[remotehost.com]:22 ([remotehost.com]:22)' can't be established. RSA key fingerprint is f7:f4:2c:e0:c6:7e:d2:a4:45:70:63:df:bf:f2:84:46. Are you sure you want to continue connecting (yes/no)? What I'm doing wrong? Why ssh.exe couldn't create directory /home/user/.ssh? Thank you.

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  • Outlook Registry Key Damaged; Tried "Fix It" and lost everything

    - by Ray
    My outlook 2007 (on Windows 7 64 bit) worked fine for two weeks. I then installed a printer/scanner/copier and the Outlook Window wouldn't open. I went to Microsoft's website and found a page that said my registry key was damaged. The page had a link to a Fix It program. I ran the program and it looks like all my Outlook data was wiped out. Can I get the data back? For future reference, how should I protect myself if the key goes bad again? Do you think I should unistall Outlook and re-install?

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  • Is it secure to store the cert/key on a private AMI?

    - by Phillip Oldham
    Are there any major security implications to bundling a private AMI which contains the private key/certificate & environment variables? For resiliency I'm creating an EC2 image which should be able to boot and configure itself without any intervention. After boot it will attempt to: Attach & mount specific EBS volume(s) Associate a specific Elastic IP Start issuing backups of the EBS volume(s) to S3 However, to do this it will need the private key/pem files and will need certain environment variables to be available on start-up. Since this is a private AMI I'm wondering if it will be "safe" to store these variables/files directly in the image so that I don't need to specify any user-data information and can therefore start a new instance remotely (from my iPhone, if needed) should the instance be terminated for any reason.

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  • How to specify an SSH key for Hudson with git plugin?

    - by jlpp
    I've got Hudson (continuous integration system) with the git plugin running on a Tomcat Windows Service. msysgit is installed and the msysgit bin dir is in the path. PuTTY/Pageant/plink are installed and msysgit is configured to use them. The trouble I'm running in to, I think, is that the user who owns the Tomcat/Hudson service (Local System) has no SSH key set up to be able to clone the git repository. When the git Hudson plugin tries to clone it gives the error: $ git clone -o origin git@hostname:project.git "e:\HUDSON_HOME\jobs\Project Trunk\workspace" ERROR: Error cloning remote repo 'origin' : Could not clone git@hostname:project.git ERROR: Cause: Error performing git clone -o origin git@hostname:project.git e:\HUDSON_HOME\jobs\Project Trunk\workspace Trying next repository ERROR: Could not clone from a repository FATAL: Could not clone hudson.plugins.git.GitException: Could not clone My question is, how can I set things up so that the git plugin/msysgit know to use a particular SSH private key when trying to clone? I don't think Pageant will work because the Tomcat service is running as the "Local System" user, but I may be wrong.

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  • How can I toggle Full Screen mode in Remote Desktop without a Break key?

    - by Jay Bazuzi
    My small laptop has a small keyboard, which lacks a Pause/Break key. Ctrl-Alt-Break toggles Full Screen mode in Windows Remote Desktop. Without a Break key, how can I enter Full Screen mode? I know I can exit fullscreen mode with the mouse. Maximizing the window doesn't help. This matters more on small laptops because the screens are small (so you need all the real estate you can get) and because the keyboard lacks dedicated PgUp/PgDn and other dedicated keys (so I can't easily use the RDP alternatives like Alt-PgUp).

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  • How do I restart mysql and where is my.cnf file

    - by dorelal
    I am using snow leopard mac. I installed mysql on my machine using instructions mentioned here. Everything works great. However I have two questions. 1) Where is my.cnf file? I searched the whole file system and result is empty. Is it possible that there is no my.cnf and mysql works with default values. If yes then probably I should create my.inf at /etc/mysql. Is that right? 2) How do I restar server. I know it gets started when I restart my machine. Here is what plist looks like. mysqld_safe does not let me restart server. <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0"> <dict> <key>KeepAlive</key> <true/> <key>Label</key> <string>com.mysql.mysqld</string> <key>Program</key> <string>/usr/local/mysql/bin/mysqld_safe</string> <key>RunAtLoad</key> <true/> <key>UserName</key> <string>mysql</string> <key>WorkingDirectory</key> <string>/usr/local/mysql</string> </dict> </plist>

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  • Strange LINQ to SQL Behavior

    - by mcass20
    What is wrong with the last query? Is it a bug or am I missing something? This query returns 2 records (correct): query = query.Where(Log => SqlMethods.Like(Log.FormattedMessage, "%<key>Name</key><value>David</value>%")); This query returns 2 records (correct): query = query.Where(Log => SqlMethods.Like(Log.FormattedMessage, "%<key>Name</key><value>%David%</value>%")); This query returns 0 records (correct): query = query.Where(Log => SqlMethods.Like(Log.FormattedMessage, "%<key>Name</key><value>av</value>%")); This query returns 2 records (correct): query = query.Where(Log => SqlMethods.Like(Log.FormattedMessage, "%<key>Name</key><value>%av%</value>%")); This query returns 0 records (correct): query = query.Where(Log => SqlMethods.Like(Log.FormattedMessage, "%<key>Name</key><value>v</value>%")); This query returns 15 records (incorrect, should return 2): query = query.Where(Log => SqlMethods.Like(Log.FormattedMessage, "%<key>Name</key><value>%v%</value>%"));

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  • Ruby - Writing Hpricot data to a file

    - by John
    Hey everyone, I am currently doing some XML parsing and I've chosen to use Hpricot because of it's ease of use and syntax, however I am running into some problems. I need to write a piece of XML data that I have found out to another file. However, when I do this the format is not preserved. For example, if the content should look like this: <dict> <key>item1</key><value>12345</value> <key>item2</key><value>67890</value> <key>item3</key><value>23456</value> </dict> And assuming that there are many entries like this in the document. I am iterating through the 'dict' items by using hpricot_element = Hpricot(xml_document_body) f = File.new('some_new_file.xml') (hpricot_element/:dict).each { |dict| f.write( dict.to_original_html ) } After using the above code, I would expect that the output look like the following exactly like the XML shown above. However to my surprise, the output of the file looks more like this: <dict>\n", " <key>item1</key><value>12345</value>\n", " <key>item2</key><value>67890</value>\n", " <key>item3</key><value>23456</value\n", " </dict> I've tried splitting at the "\n" characters and writing to the file one line at a time, but that didn't seem to work either as it did not recognize the "\n" characters. Any help is greatly appreciated. It might be a very simple solution, but I am having troubling finding it. Thanks!

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  • Editing a sublime theme, how to know which key string corresponds to which text element in the code?

    - by laggingreflex
    I want to customize the color scheme of the comments in my code, by editing the .tmTheme How to know which of the <dict> <key> corresponds to which element of the code? Like, I can guess some of them but not every one of them is that obvious.. I remember there was some mouse click or a keyboard shortcut that when you hover over something in your code and click/press it it would show exactly the key you need to edit in the status bar. Something like this How do I do that?

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  • how to skip first 3 row of text file.

    - by Dilantha Chamal
    hey when i reading the text file using java, how can i skip first 3 rows of the text file. Show me how to do that. public class Reader { public static void main(String[] args) { BufferedReader reader; try { reader = new BufferedReader(new InputStreamReader( new FileInputStream("sample.txt"))); Map<String, Integer result = new LinkedHashMap<String, Integer(); Map<String, Integer result2 = new LinkedHashMap<String, Integer(); while (reader.ready()) { String line = reader.readLine(); /split a line with spaces/ String[] values = line.split("\s+"); /set a key date\tanimal/ String key = values[0] + "\t" + values[1]; int sum = 0; int count = 0; /get a last counter and sum/ if (result.containsKey(key)) { sum = result.get(key); count = result2.get(key); } else{ } /increment sum a count and save in the map with key/ result.put(key, sum + Integer.parseInt(values[2])); result2.put(key, count + 1); } /interate and print new output/ for (String key : result.keySet()) { Integer sum = result.get(key); Integer count = result2.get(key); System.out.println(key + " " + sum + "\t" + count); } reader.close(); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } }

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  • How Can I Find My Windows 7 Pro Product Key is Original?

    - by user29373
    Our Company Wants to buy 30 windows 7 pro OEM License. and somebody gave us some package like this http://www.citymax.co.nz/45-91-thickbox/windows-7-professional-oem.jpg 1- I want to know that Does this Windows 7 Pro Package is Original and genuine?How can I sure that? 2- How Can I understand how many user can use this Windows? He gave us for 30 client but what happen if we install this package for more than that? How can I find the number of user can install this? 3- How can I check the Product Key before installing Windows? Has microsoft site for checking product key?

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  • Booting sequence. Ubuntu 12.04 installation and cohabitation with former OSes

    - by Stephane Rolland
    I am on the brink of installing Ubuntu 12.04 Precise Pengolin on the first primary partition of my hard-drive. (A day in History for me since I had always kept a MS windows at this first place). But I have some fears: This is my last computer available (In the past I used to have 2 or even 3 machines so I could always un/plug HDs for recovery operations and rescue) The current booting sequence is not straight forard. So as to explain the boot sequence let me briefly sum-up the history of this laptop computer. It was a dedicated Windows Vista computer. 1st and only Primary partition. Then I added Windows 7 (on the 2nd primary partition) letting the Windows Vista Boot Loader manage the boot sequence. Then I added Ubuntu 10.04 Lucid Lynx on the 1st sub-partition of the Extended Partitionm asking Grub to be the boot loader. But when I ask Grub to launch windows it launches the Vista BootLoader that manages the choice betzeen Vista and 7. So in theory Grub is on the MasterBootRecord - though I understand where the Vista BootLoader remains. Now, I will no longer use the Ubuntu 10.04 ( on extended partition) and also the Windows vista (on the first primary partition). I will install Ubuntu 12.04 on the First Primary, asking it to install a new bootloader. I want to keep the Windows 7 that is already on the Second Primary partition. And I want it to be loaded by the Ubuntu Boot loader(I don4t knoz zhich is included in this version)... And I am afraid the last point will not work.

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  • DB Schema for ACL involving 3 subdomains

    - by blacktie24
    Hi, I am trying to design a database schema for a web app which has 3 subdomains: a) internal employees b) clients c) contractors. The users will be able to communicate with each other to some degree, and there may be some resources that overlap between them. Any thoughts about this schema? Really appreciate your time and thoughts on this. Cheers! -- -- Table structure for table locations CREATE TABLE IF NOT EXISTS locations ( id bigint(20) NOT NULL, name varchar(250) NOT NULL ) ENGINE=InnoDB DEFAULT CHARSET=latin1; -- -- Table structure for table privileges CREATE TABLE IF NOT EXISTS privileges ( id int(11) NOT NULL AUTO_INCREMENT, name varchar(255) NOT NULL, resource_id int(11) NOT NULL, PRIMARY KEY (id) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=10 ; -- -- Table structure for table resources CREATE TABLE IF NOT EXISTS resources ( id int(11) NOT NULL AUTO_INCREMENT, name varchar(255) NOT NULL, user_type enum('internal','client','expert') NOT NULL, PRIMARY KEY (id) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=3 ; -- -- Table structure for table roles CREATE TABLE IF NOT EXISTS roles ( id int(11) NOT NULL AUTO_INCREMENT, name varchar(255) NOT NULL, type enum('position','department') NOT NULL, parent_id int(11) DEFAULT NULL, user_type enum('internal','client','expert') NOT NULL, PRIMARY KEY (id) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=3 ; -- -- Table structure for table role_perms CREATE TABLE IF NOT EXISTS role_perms ( id int(11) NOT NULL AUTO_INCREMENT, role_id int(11) NOT NULL, privilege_id int(11) NOT NULL, mode varchar(250) NOT NULL, PRIMARY KEY (id) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=2 ; -- -- Table structure for table users CREATE TABLE IF NOT EXISTS users ( id int(10) unsigned NOT NULL AUTO_INCREMENT, email varchar(255) NOT NULL, password varchar(255) NOT NULL, salt varchar(255) NOT NULL, type enum('internal','client','expert') NOT NULL, first_name varchar(255) NOT NULL, last_name varchar(255) NOT NULL, location_id int(11) NOT NULL, phone varchar(255) NOT NULL, status enum('active','inactive') NOT NULL DEFAULT 'active', PRIMARY KEY (id) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=4 ; -- -- Table structure for table user_perms CREATE TABLE IF NOT EXISTS user_perms ( id int(11) NOT NULL AUTO_INCREMENT, user_id int(11) NOT NULL, privilege_id int(11) NOT NULL, mode varchar(250) NOT NULL, PRIMARY KEY (id) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=2 ; -- -- Table structure for table user_roles CREATE TABLE IF NOT EXISTS user_roles ( id int(11) NOT NULL, user_id int(11) NOT NULL, role_id int(11) NOT NULL ) ENGINE=InnoDB DEFAULT CHARSET=latin1;

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  • C# 4: The Curious ConcurrentDictionary

    - by James Michael Hare
    In my previous post (here) I did a comparison of the new ConcurrentQueue versus the old standard of a System.Collections.Generic Queue with simple locking.  The results were exactly what I would have hoped, that the ConcurrentQueue was faster with multi-threading for most all situations.  In addition, concurrent collections have the added benefit that you can enumerate them even if they're being modified. So I set out to see what the improvements would be for the ConcurrentDictionary, would it have the same performance benefits as the ConcurrentQueue did?  Well, after running some tests and multiple tweaks and tunes, I have good and bad news. But first, let's look at the tests.  Obviously there's many things we can do with a dictionary.  One of the most notable uses, of course, in a multi-threaded environment is for a small, local in-memory cache.  So I set about to do a very simple simulation of a cache where I would create a test class that I'll just call an Accessor.  This accessor will attempt to look up a key in the dictionary, and if the key exists, it stops (i.e. a cache "hit").  However, if the lookup fails, it will then try to add the key and value to the dictionary (i.e. a cache "miss").  So here's the Accessor that will run the tests: 1: internal class Accessor 2: { 3: public int Hits { get; set; } 4: public int Misses { get; set; } 5: public Func<int, string> GetDelegate { get; set; } 6: public Action<int, string> AddDelegate { get; set; } 7: public int Iterations { get; set; } 8: public int MaxRange { get; set; } 9: public int Seed { get; set; } 10:  11: public void Access() 12: { 13: var randomGenerator = new Random(Seed); 14:  15: for (int i=0; i<Iterations; i++) 16: { 17: // give a wide spread so will have some duplicates and some unique 18: var target = randomGenerator.Next(1, MaxRange); 19:  20: // attempt to grab the item from the cache 21: var result = GetDelegate(target); 22:  23: // if the item doesn't exist, add it 24: if(result == null) 25: { 26: AddDelegate(target, target.ToString()); 27: Misses++; 28: } 29: else 30: { 31: Hits++; 32: } 33: } 34: } 35: } Note that so I could test different implementations, I defined a GetDelegate and AddDelegate that will call the appropriate dictionary methods to add or retrieve items in the cache using various techniques. So let's examine the three techniques I decided to test: Dictionary with mutex - Just your standard generic Dictionary with a simple lock construct on an internal object. Dictionary with ReaderWriterLockSlim - Same Dictionary, but now using a lock designed to let multiple readers access simultaneously and then locked when a writer needs access. ConcurrentDictionary - The new ConcurrentDictionary from System.Collections.Concurrent that is supposed to be optimized to allow multiple threads to access safely. So the approach to each of these is also fairly straight-forward.  Let's look at the GetDelegate and AddDelegate implementations for the Dictionary with mutex lock: 1: var addDelegate = (key,val) => 2: { 3: lock (_mutex) 4: { 5: _dictionary[key] = val; 6: } 7: }; 8: var getDelegate = (key) => 9: { 10: lock (_mutex) 11: { 12: string val; 13: return _dictionary.TryGetValue(key, out val) ? val : null; 14: } 15: }; Nothing new or fancy here, just your basic lock on a private object and then query/insert into the Dictionary. Now, for the Dictionary with ReadWriteLockSlim it's a little more complex: 1: var addDelegate = (key,val) => 2: { 3: _readerWriterLock.EnterWriteLock(); 4: _dictionary[key] = val; 5: _readerWriterLock.ExitWriteLock(); 6: }; 7: var getDelegate = (key) => 8: { 9: string val; 10: _readerWriterLock.EnterReadLock(); 11: if(!_dictionary.TryGetValue(key, out val)) 12: { 13: val = null; 14: } 15: _readerWriterLock.ExitReadLock(); 16: return val; 17: }; And finally, the ConcurrentDictionary, which since it does all it's own concurrency control, is remarkably elegant and simple: 1: var addDelegate = (key,val) => 2: { 3: _concurrentDictionary[key] = val; 4: }; 5: var getDelegate = (key) => 6: { 7: string s; 8: return _concurrentDictionary.TryGetValue(key, out s) ? s : null; 9: };                    Then, I set up a test harness that would simply ask the user for the number of concurrent Accessors to attempt to Access the cache (as specified in Accessor.Access() above) and then let them fly and see how long it took them all to complete.  Each of these tests was run with 10,000,000 cache accesses divided among the available Accessor instances.  All times are in milliseconds. 1: Dictionary with Mutex Locking 2: --------------------------------------------------- 3: Accessors Mostly Misses Mostly Hits 4: 1 7916 3285 5: 10 8293 3481 6: 100 8799 3532 7: 1000 8815 3584 8:  9:  10: Dictionary with ReaderWriterLockSlim Locking 11: --------------------------------------------------- 12: Accessors Mostly Misses Mostly Hits 13: 1 8445 3624 14: 10 11002 4119 15: 100 11076 3992 16: 1000 14794 4861 17:  18:  19: Concurrent Dictionary 20: --------------------------------------------------- 21: Accessors Mostly Misses Mostly Hits 22: 1 17443 3726 23: 10 14181 1897 24: 100 15141 1994 25: 1000 17209 2128 The first test I did across the board is the Mostly Misses category.  The mostly misses (more adds because data requested was not in the dictionary) shows an interesting trend.  In both cases the Dictionary with the simple mutex lock is much faster, and the ConcurrentDictionary is the slowest solution.  But this got me thinking, and a little research seemed to confirm it, maybe the ConcurrentDictionary is more optimized to concurrent "gets" than "adds".  So since the ratio of misses to hits were 2 to 1, I decided to reverse that and see the results. So I tweaked the data so that the number of keys were much smaller than the number of iterations to give me about a 2 to 1 ration of hits to misses (twice as likely to already find the item in the cache than to need to add it).  And yes, indeed here we see that the ConcurrentDictionary is indeed faster than the standard Dictionary here.  I have a strong feeling that as the ration of hits-to-misses gets higher and higher these number gets even better as well.  This makes sense since the ConcurrentDictionary is read-optimized. Also note that I tried the tests with capacity and concurrency hints on the ConcurrentDictionary but saw very little improvement, I think this is largely because on the 10,000,000 hit test it quickly ramped up to the correct capacity and concurrency and thus the impact was limited to the first few milliseconds of the run. So what does this tell us?  Well, as in all things, ConcurrentDictionary is not a panacea.  It won't solve all your woes and it shouldn't be the only Dictionary you ever use.  So when should we use each? Use System.Collections.Generic.Dictionary when: You need a single-threaded Dictionary (no locking needed). You need a multi-threaded Dictionary that is loaded only once at creation and never modified (no locking needed). You need a multi-threaded Dictionary to store items where writes are far more prevalent than reads (locking needed). And use System.Collections.Concurrent.ConcurrentDictionary when: You need a multi-threaded Dictionary where the writes are far more prevalent than reads. You need to be able to iterate over the collection without locking it even if its being modified. Both Dictionaries have their strong suits, I have a feeling this is just one where you need to know from design what you hope to use it for and make your decision based on that criteria.

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  • PHP + Code Igniter Timecode Calculation Logic Error

    - by Tim
    Hello everyone, I have what I suspect to be a logic problem with an algorithm I am using to work with Video timecode in PHP. All help is appreciated. The Objective Well basically I want to work with timecode and perform calculations For those not familiar with timecode it looks like this 01:10:58:12 or HH:MM:SS:FF 'AKA' HOURS:MINUTES:SECONDS:FRAMES I have used the script from HERE to help me with working with this format. The Problem Now can i just say that this script works!!! Timecode calculations (in this case additions) are being performed correctly. However this script continually throws the following errors, yet still produces the correct output when I try and do the following calculation 00:01:26:00 + 00:02:00:12 The errors from this calculation are shown below A PHP Error was encountered Severity: Notice Message: Undefined index: key Filename: staff/tools.php Line Number: 169 A PHP Error was encountered Severity: Notice Message: Undefined index: key Filename: staff/tools.php Line Number: 169 Line Number 169 is in the parseInput() function // feed it into the tc array $i=0; foreach ($tc AS $key=>$value) { if ( is_numeric($array["$i"]) ) { $tc["$key"]= $array["$i"]; if ($tc["$key"] < 10 && $tc["$key"] > 0 && strlen($tc['key'])==1 ) $tc["$key"]= "0".$tc["$key"]; } $i++; } return $tc; Now I should also mention that the number of times the above error is thrown depends on what I am calculating 00:00:00:00 + 00:00:00:00 returns no errors. 01:01:01:01 + 02:02:02:02 produces 8 of the above errors. For your reference, here is the code in it's entirety function add_cue_sheet_clips_process() { $sheetID = $_POST['sheet_id']; $clipName = $_POST['clip_name']; $tcIn = $_POST['tc_in']; $tcOut = $_POST['tc_out']; // string $input // returns an associative array of hours, minutes, seconds, and frames // function parseInput ($input) { // timecode should look something like hh:mm:ss;ff // allowed separators are : ; . , // values may be single or double digits // hours are least-significant -- 5.4 == 00:00:05;04 $tc= array("frames"=>"00", "seconds"=>"00", "minutes"=>"00", "hours"=>"00"); $punct= array(":", ";", ".", ","); // too big? too small? $input= trim($input); if (strlen($input)>11 || $input=="") { // invalid input, too long -- bzzt return $tc; } // normalize punctuation $input= str_replace( $punct, ":", $input); // blow it up and reverse it so frames come first $array= explode(":", $input); $array= array_reverse($array); // feed it into the tc array $i=0; foreach ($tc AS $key=>$value) { if ( is_numeric($array["$i"]) ) { $tc["$key"]= $array["$i"]; if ($tc["$key"] < 10 && $tc["$key"] > 0 && strlen($tc['key'])==1 ) $tc["$key"]= "0".$tc["$key"]; } $i++; } return $tc; } // array $tc // returns a float number of seconds // function tcToSec($tc) { $wholeseconds= ($tc['hours']*3600) + ($tc['minutes'] * 60) + ($tc['seconds']); $partseconds= ( $tc['frames'] / 25 ); $seconds= $wholeseconds + $partseconds; return $seconds; } // float $seconds // bool $subtract // returns a timecode array // function secToTc ($seconds=0, $subtract=0) { $tc= array("frames"=>"00", "seconds"=>"00", "minutes"=>"00", "hours"=>"00"); $partseconds= fmod($seconds, 1); $wholeseconds= $seconds - $partseconds; // frames if ($subtract==1) $tc['frames']= floor( $partseconds * 25 ); else $tc['frames']= floor( $partseconds * 25 ); // hours $tc['hours']= floor( $wholeseconds / 3600 ); $minsec= ($wholeseconds - ($tc['hours'] * 3600)); // minutes $tc['minutes']= floor( $minsec / 60 ); // seconds $tc['seconds']= ( $minsec - ($tc['minutes'] * 60) ); // padding foreach ( $tc AS $key=>$value ) { if ($value > 0 && $value < 10) $tc["$key"]= "0".$value; if ($value=="0") $tc["$key"]= "00"; } return $tc; } // array $tc // returns string of well-formed timecode // function tcToString (&$tc) { return $tc['hours'].":".$tc['minutes'].":".$tc['seconds'].";".$tc['frames']; } $timecodeIN = parseInput($tcIn); $timecodeOUT = parseInput($tcOut); // normalized inputs... $tc1 = tcToString($timecodeIN); $tc2 = tcToString($timecodeOUT); // get seconds $seconds1 = tcToSec($timecodeIN); $seconds2 = tcToSec($timecodeOUT); $result = $seconds1 + $seconds2; $timecode3 = secToTc($result, 0); $timecodeDUR = tcToString($timecode3); $clipArray = array('clip_name' => $clipName, 'tc_in' => $tcIn, 'tc_out' => $tcOut, 'tc_duration' => $timecodeDUR); $this->db->insert('tools_cue_sheets_clips', $clipArray); redirect('staff/tools/add_cue_sheet_clips/'.$sheetID); } I hope this is enough information for someone to help me get on top of this, I would be extremely greatful. Thanks, Tim

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  • wierd keyboard problem

    - by Sebastian
    just installed ubuntu on a acer extensa 5620 laptop. The keyboard works fine except when i want to type things that require me to use ctrl+alt+(any key), i can't use ctrl+alt+(any key) in any program, I can open terminal with ctrl+alt+t tho... and ctrl+(any key) and alt+(any key) seems to work. Also I just installed the game Heroes of Newerth and neither alt or ctrl key seems to work in the game. Any answer would be appreciated!

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  • Loading any MVC page fails with the error "An item with the same key has already been added."

    - by MajorRefactoring
    I am having an intermittent issue that is appearing on one server only, and is causing all MVC pages to fail to load with the error "An item with the same key has already been added." Restarting the application pool fixes the issue, but until then, loading any mvc page throws the following exception: Event code: 3005 Event message: An unhandled exception has occurred. Event time: 10/11/2012 08:09:24 Event time (UTC): 10/11/2012 08:09:24 Event ID: d76264aedc4241d4bce9247692510466 Event sequence: 6407 Event occurrence: 30 Event detail code: 0 Application information: Application domain: /LM/W3SVC/21/ROOT-2-129969647741292058 Trust level: Full Application Virtual Path: / Application Path: d:\websites\SiteAndAppPoolName\ Machine name: UKSERVER Process information: Process ID: 6156 Process name: w3wp.exe Account name: IIS APPPOOL\SiteAndAppPoolName Exception information: Exception type: ArgumentException Exception message: An item with the same key has already been added. Server stack trace: at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add) at System.Linq.Enumerable.ToDictionary[TSource,TKey,TElement](IEnumerable`1 source, Func`2 keySelector, Func`2 elementSelector, IEqualityComparer`1 comparer) at System.Web.WebPages.Scope.WebConfigScopeDictionary.<>c__DisplayClass4.<.ctor>b__0() at System.Lazy`1.CreateValue() Exception rethrown at [0]: at System.Lazy`1.get_Value() at System.Web.WebPages.Scope.WebConfigScopeDictionary.TryGetValue(Object key, Object& value) at System.Web.Mvc.ViewContext.ScopeGet[TValue](IDictionary`2 scope, String name, TValue defaultValue) at System.Web.Mvc.ViewContext.ScopeCache.Get(IDictionary`2 scope, HttpContextBase httpContext) at System.Web.Mvc.ViewContext.GetClientValidationEnabled(IDictionary`2 scope, HttpContextBase httpContext) at System.Web.Mvc.Html.FormExtensions.FormHelper(HtmlHelper htmlHelper, String formAction, FormMethod method, IDictionary`2 htmlAttributes) at System.Web.Mvc.Html.FormExtensions.BeginForm(HtmlHelper htmlHelper, String actionName, String controllerName) at ASP._Page_Views_Dashboard_Functions_BookingQuickLookup_cshtml.Execute() in d:\Websites\SiteAndAppPoolName\Views\Dashboard\Functions\BookingQuickLookup.cshtml:line 3 at System.Web.WebPages.WebPageBase.ExecutePageHierarchy() at System.Web.Mvc.WebViewPage.ExecutePageHierarchy() at System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage) at System.Web.Mvc.Html.PartialExtensions.Partial(HtmlHelper htmlHelper, String partialViewName, Object model, ViewDataDictionary viewData) at ASP._Page_Views_Dashboard_Functions_cshtml.Execute() in d:\Websites\SiteAndAppPoolName\Views\Dashboard\Functions.cshtml:line 5 at System.Web.WebPages.WebPageBase.ExecutePageHierarchy() at System.Web.Mvc.WebViewPage.ExecutePageHierarchy() at System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage) at System.Web.Mvc.Html.RenderPartialExtensions.RenderPartial(HtmlHelper htmlHelper, String partialViewName, Object model) at ASP._Page_Views_Dashboard_Index_cshtml.Execute() in d:\Websites\SiteAndAppPoolName\Views\Dashboard\Index.cshtml:line 9 at System.Web.WebPages.WebPageBase.ExecutePageHierarchy() at System.Web.Mvc.WebViewPage.ExecutePageHierarchy() at System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage) at System.Web.Mvc.ViewResultBase.ExecuteResult(ControllerContext context) at System.Web.Mvc.ControllerActionInvoker.<>c__DisplayClass1c.<InvokeActionResultWithFilters>b__19() at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilter(IResultFilter filter, ResultExecutingContext preContext, Func`1 continuation) at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilter(IResultFilter filter, ResultExecutingContext preContext, Func`1 continuation) at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext, IList`1 filters, ActionResult actionResult) at System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext, String actionName) at System.Web.Mvc.Controller.ExecuteCore() at System.Web.Mvc.ControllerBase.Execute(RequestContext requestContext) at System.Web.Mvc.MvcHandler.<>c__DisplayClass6.<>c__DisplayClassb.<BeginProcessRequest>b__5() at System.Web.Mvc.Async.AsyncResultWrapper.<>c__DisplayClass1.<MakeVoidDelegate>b__0() at System.Web.Mvc.MvcHandler.<>c__DisplayClasse.<EndProcessRequest>b__d() at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) Request information: Request URL: http://SiteAndAppPoolName.spawtz.com/Dashboard Request path: /Dashboard User host address: 86.164.135.41 User: Is authenticated: False Authentication Type: Thread account name: IIS APPPOOL\SiteAndAppPoolName Thread information: Thread ID: 17 Thread account name: IIS APPPOOL\SiteAndAppPoolName Is impersonating: False Stack trace: at System.Lazy`1.get_Value() at System.Web.WebPages.Scope.WebConfigScopeDictionary.TryGetValue(Object key, Object& value) at System.Web.Mvc.ViewContext.ScopeGet[TValue](IDictionary`2 scope, String name, TValue defaultValue) at System.Web.Mvc.ViewContext.ScopeCache.Get(IDictionary`2 scope, HttpContextBase httpContext) at System.Web.Mvc.ViewContext.GetClientValidationEnabled(IDictionary`2 scope, HttpContextBase httpContext) at System.Web.Mvc.Html.FormExtensions.FormHelper(HtmlHelper htmlHelper, String formAction, FormMethod method, IDictionary`2 htmlAttributes) at System.Web.Mvc.Html.FormExtensions.BeginForm(HtmlHelper htmlHelper, String actionName, String controllerName) at ASP._Page_Views_Dashboard_Functions_BookingQuickLookup_cshtml.Execute() in d:\Websites\SiteAndAppPoolName\Views\Dashboard\Functions\BookingQuickLookup.cshtml:line 3 at System.Web.WebPages.WebPageBase.ExecutePageHierarchy() at System.Web.Mvc.WebViewPage.ExecutePageHierarchy() at System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage) at System.Web.Mvc.Html.PartialExtensions.Partial(HtmlHelper htmlHelper, String partialViewName, Object model, ViewDataDictionary viewData) at ASP._Page_Views_Dashboard_Functions_cshtml.Execute() in d:\Websites\SiteAndAppPoolName\Views\Dashboard\Functions.cshtml:line 5 at System.Web.WebPages.WebPageBase.ExecutePageHierarchy() at System.Web.Mvc.WebViewPage.ExecutePageHierarchy() at System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage) at System.Web.Mvc.Html.RenderPartialExtensions.RenderPartial(HtmlHelper htmlHelper, String partialViewName, Object model) at ASP._Page_Views_Dashboard_Index_cshtml.Execute() in d:\Websites\SiteAndAppPoolName\Views\Dashboard\Index.cshtml:line 9 at System.Web.WebPages.WebPageBase.ExecutePageHierarchy() at System.Web.Mvc.WebViewPage.ExecutePageHierarchy() at System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage) at System.Web.Mvc.ViewResultBase.ExecuteResult(ControllerContext context) at System.Web.Mvc.ControllerActionInvoker.<>c__DisplayClass1c.<InvokeActionResultWithFilters>b__19() at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilter(IResultFilter filter, ResultExecutingContext preContext, Func`1 continuation) at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilter(IResultFilter filter, ResultExecutingContext preContext, Func`1 continuation) at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext, IList`1 filters, ActionResult actionResult) at System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext, String actionName) at System.Web.Mvc.Controller.ExecuteCore() at System.Web.Mvc.ControllerBase.Execute(RequestContext requestContext) at System.Web.Mvc.MvcHandler.<>c__DisplayClass6.<>c__DisplayClassb.<BeginProcessRequest>b__5() at System.Web.Mvc.Async.AsyncResultWrapper.<>c__DisplayClass1.<MakeVoidDelegate>b__0() at System.Web.Mvc.MvcHandler.<>c__DisplayClasse.<EndProcessRequest>b__d() at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) Custom event details: As mentioned, it's every MVC action that throws this error until the app pool is restarted, and the error seems to be occurring in System.Web.WebPages.Scope.WebConfigScopeDictionary.TryGetValue(Object key, Object& value) Has anyone seen this issue before? It's only happening on this server, on any of the app pools on the server (not confined to this one) and an app pool restart sorts it. Any help much appreciated. Cheers, Matthew

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  • 3rd party data - Store in Data Warehouse or Primary database?

    - by brydgesk
    This is mostly a data warehouse philosophy question. My project involves an Oracle forms application, and a Teradata Data Warehouse for reporting and ad-hoc purposes. In addition to the primary data created by the users of our application, we also require data from various other sources. Currently, this 3rd party data comes via FTPd flat files directly to our Data Warehouse. To access the data, our users must use a series of custom BusinessObjects reports. My question is, would it make more sense for this data to be sent to our source Oracle system instead? Is it ever appropriate for a Data Warehouse to be the point of origin for users to access raw data? In short, is it more important that the operational database contain only the data created by your project, or that the data warehouse remain dedicated solely to reporting and analysis?

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