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  • Calendar Table - Week number of month

    - by Saif Khan
    I have a calendar table with data from year 2000 to 2012 (2012 wasn't intentional!). I just realize that I don't have the week number of month (e.g In January 1,2,3,4 February 1,2,3,4) How do I go about calculating the week numbers in a month to fill this table? Here is the table schema CREATE TABLE [TCalendar] ( [TimeKey] [int] NOT NULL , [FullDateAlternateKey] [datetime] NOT NULL , [HolidayKey] [tinyint] NULL , [IsWeekDay] [tinyint] NULL , [DayNumberOfWeek] [tinyint] NULL , [EnglishDayNameOfWeek] [nvarchar] (10) COLLATE SQL_Latin1_General_CP1_CI_AS NULL , [SpanishDayNameOfWeek] [nvarchar] (10) COLLATE SQL_Latin1_General_CP1_CI_AS NULL , [FrenchDayNameOfWeek] [nvarchar] (10) COLLATE SQL_Latin1_General_CP1_CI_AS NULL , [DayNumberOfMonth] [tinyint] NULL , [DayNumberOfYear] [smallint] NULL , [WeekNumberOfYear] [tinyint] NULL , [EnglishMonthName] [nvarchar] (10) COLLATE SQL_Latin1_General_CP1_CI_AS NULL , [SpanishMonthName] [nvarchar] (10) COLLATE SQL_Latin1_General_CP1_CI_AS NULL , [FrenchMonthName] [nvarchar] (10) COLLATE SQL_Latin1_General_CP1_CI_AS NULL , [MonthNumberOfYear] [tinyint] NULL , [CalendarQuarter] [tinyint] NULL , [CalendarYear] [char] (4) COLLATE SQL_Latin1_General_CP1_CI_AS NULL , [CalendarSemester] [tinyint] NULL , [FiscalQuarter] [tinyint] NULL , [FiscalYear] [char] (4) COLLATE SQL_Latin1_General_CP1_CI_AS NULL , [FiscalSemester] [tinyint] NULL , [IsLastDayInMonth] [tinyint] NULL , CONSTRAINT [PK_TCalendar] PRIMARY KEY CLUSTERED ( [TimeKey] ) ON [PRIMARY] ) ON [PRIMARY] GO

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  • Assets.getBytes returns null in test environment

    - by ashes999
    I'm using the latest Haxe (2.10), NME (3.4.3), and MUnit. I've written some unit tests that need to fetch bitmap data from SWF symbols. The first step is to actually load the SWF data. To do this, I use NME's getByteArray along with the swf library, like so: var blah:SWF = new SWF(Assets.getBytes("assets/swf/test.swf")); The call to Assets.getBytes returns null when I'm running this under MUnit. When running my actual game code, I'm able to get the byte array (and consequentially, instantiate the SWF class). Am I doing something wrong? What am I missing? Edit: My directory structure is: . (root .\assets .\assets\*.png (other images) .\assets\swf\*.swf (SWFs) .\Source\*.hx (source code) .\Test\*.hx (tests)

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  • Binary Tree operator overloading and recursion

    - by furious.snail
    I was wondering how to overload the == operator for a binary tree to compare if two trees have identical data at same nodes. So far this is what I have: bool TreeType::operator==(const TreeType& otherTree) const { if((root == NULL) && (otherTree.root == NULL)) return true; //two null trees are equal else if((root != NULL) && (otherTree.root != NULL)) { return((root-info == otherTree.root-info) && //this part doesn't actually do anything recursively... //(root-left == otherTree.root-left) && //(root-right == otherTree.root-right)) } else return false; //one tree is null the other is not } I have a similar function that takes two TreeNode pointers as parameters but I've been stuck on how to convert it to this function.

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  • Application not releasing database connection Spring.net + NHibernate

    - by anupam3m
    Even after successful transaction.Application connection with the database persist.in Nhibernate log it shows Nhibernate Log 2010-05-21 14:45:08,428 [Worker] [0] DEBUG NHibernate.Impl.SessionImpl [(null)] <(null) - executing flush 2010-05-21 14:45:08,428 [Worker] [0] DEBUG NHibernate.Impl.ConnectionManager [(null)] <(null) - registering flush begin 2010-05-21 14:45:08,428 [Worker] [0] DEBUG NHibernate.Impl.ConnectionManager [(null)] <(null) - registering flush end 2010-05-21 14:45:08,428 [Worker] [0] DEBUG NHibernate.Impl.SessionImpl [(null)] <(null) - post flush 2010-05-21 14:45:08,428 [Worker] [0] DEBUG NHibernate.Impl.SessionImpl [(null)] <(null) - before transaction completion 2010-05-21 14:45:08,428 [Worker] [0] DEBUG NHibernate.Impl.ConnectionManager [(null)] <(null) - aggressively releasing database connection 2010-05-21 14:45:08,428 [Worker] [0] DEBUG NHibernate.Connection.ConnectionProvider [(null)] <(null) - Closing connection 2010-05-21 14:45:08,428 [Worker] [0] DEBUG NHibernate.Impl.SessionImpl [(null)] <(null) - transaction completion 2010-05-21 14:45:08,428 [Worker] [0] DEBUG NHibernate.Transaction.AdoTransaction [(null)] <(null) - running AdoTransaction.Dispose() 2010-05-21 14:45:08,428 [Worker] [0] DEBUG NHibernate.Impl.SessionImpl [(null)] <(null) - closing session 2010-05-21 14:45:08,428 [Worker] [0] DEBUG NHibernate.Impl.BatcherImpl [(null)] <(null) - running BatcherImpl.Dispose(true) Underneath given is my dataconfiguration file -- Risco.Rsp.Ac.RMAC.Mapping Risco.Rsp.Ac.Logging.Appenders -- Please help me out with this issue.Thanks

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  • TypeError: Cannot call method 'hasOwnProperty' of null, while creating a QMLscene window

    - by tomoqv
    I am trying to make a simple Ubuntu Touch web application with Qt Creator. I have set up a new project according to the tutorial and committed the files to Bazaar. I have set a url instead of the default index.htm in the qml file of the project. Using build-run loads a QML Scene window with the desired webpage, but Qt Creator yields the following output: Starting /usr/lib/i386-linux-gnu/qt5/bin/qmlscene -I /home/tomas/ubuntu-sdk/SL-planner -I /usr/bin -I /usr/lib/i386-linux-gnu/qt5/qml /home/tomas/ubuntu-sdk/SL-planner/SL-planner.qml unity::action::ActionManager::ActionManager(QObject*): Could not determine application identifier. HUD will not work properly. Provide your application identifier in $APP_ID environment variable. file:///usr/lib/i386-linux-gnu/qt5/qml/Ubuntu/Components/MainView.qml:257: TypeError: Cannot call method 'hasOwnProperty' of null My SL-planner.qml looks like this: import QtQuick 2.0 import Ubuntu.Components 0.1 import QtWebKit 3.0 /*! \brief MainView with a Flickable WebView. */ MainView { // objectName for functional testing purposes (autopilot-qt5) objectName: "mainView" // Note! applicationName needs to match the "name" field of the click manifest applicationName: "com.ubuntu.developer.tomoqv.SL-planner" /* This property enables the application to change orientation when the device is rotated. The default is false. */ automaticOrientation: true width: units.gu(100) height: units.gu(75) Flickable { id: webViewFlickable anchors.fill: parent WebView { id: webView anchors.fill: parent url: "http://mobil.sl.se" } } } What am I missing?

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  • Why does glGetString returns a NULL string

    - by snape
    I am trying my hands at GLFW library. I have written a basic program to get OpenGL renderer and vendor string. Here is the code #include <GL/glew.h> #include <GL/glfw.h> #include <cstdio> #include <cstdlib> #include <string> using namespace std; void shutDown(int returnCode) { printf("There was an error in running the code with error %d\n",returnCode); GLenum res = glGetError(); const GLubyte *errString = gluErrorString(res); printf("Error is %s\n", errString); glfwTerminate(); exit(returnCode); } int main() { // start GL context and O/S window using GLFW helper library if (glfwInit() != GL_TRUE) shutDown(1); if (glfwOpenWindow(0, 0, 0, 0, 0, 0, 0, 0, GLFW_WINDOW) != GL_TRUE) shutDown(2); // start GLEW extension handler glewInit(); // get version info const GLubyte* renderer = glGetString (GL_RENDERER); // get renderer string const GLubyte* version = glGetString (GL_VERSION); // version as a string printf("Renderer: %s\n", renderer); printf("OpenGL version supported %s\n", version); // close GL context and any other GLFW resources glfwTerminate(); return 0; } I googled this error and found out that we have to initialize the OpenGL context before calling glGetString(). Although I have initialized OpenGL context using glfwInit() but still the function returns a NULL string. Any ideas? Edit I have updated the code with error checking mechanisms. This code on running outputs the following There was an error in running the code with error 2 Error is no error

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  • RasterizerState set to null after calling DrawText in Nuclex

    - by ProgrammerAtWork
    I have the following code in XNA: // class members Text t1; Text t2; Text t3; // init // Debugfont is size 24 vectorfont t1 = MM.DebugFont24.Fill("hello"); t1 = MM.DebugFont24.Extrude("hello"); t2 = MM.DebugFont24.Fill("hello"); t2 = MM.DebugFont24.Extrude("hello"); t3 = MM.DebugFont24.Fill("hello"); t3 = MM.DebugFont24.Extrude("hello"); // Draw TextBatch test = new TextBatch(MM.GD); test.DrawText(t1, Color.Red); test.DrawText(t2, Color.Red); test.DrawText(t3, Color.Red); test.End(); //After the second call to the TextBatch, RasterizerState of the GraphicsDevice is set to null //But I don't get any runtime errors or any indication of that something is wrong. Is this supposed to happen? Or am I doing something wrong? I've discovered that this happened because culling was set to None when I was rendering textures

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  • Can't remove software - Installed in NULL

    - by ChosSimbaOne
    I've installed software to our administration machine. The problem is that i cannot start the software or uninstall it, as it is not in any directory on the machine. I tried to install it at /pack/CST/... but it is not there and a locate on CST or cst returns nothing. The software is installed from a DVD and not a repository. I've tried to reboot the machine, as i thought i might had something to do with the software being loaded in some sort of tmpfs but that didn't help. I've looked through the entire /etc to check for any relations to the software, but unsuccessfully. I'm out of ideas, to what can cause this problem, anyone got any ideas?? EDIT: I downloaded the iso wich i mounted with: sudo mount -o loop /path/to/iso.iso /path/to/mountpoint sudo /path/to/mountpoint/install.sh Ran the install GUI via an X-session. I choose to install the software in /pack/CST/... but when it exited it said that the software had been installed to /tmp/... There was nothing in tmp, so i decided to reboot the machine and did a full find to see if there was anything left of the software, removed what looked like it could be related. It had placed a script in all the /etc/rs* folder which I removed with: sudo update-rc.d -f scriptname -r I rebooted the machine again, just to be sure. When i run the installer again, it tells me that the software is installed in NULL and i have to remove before installing it. /pack/ is a mountpoint for /q/system/pack What i expected was that the software would be installed in /pack/CST, but it seems to be lock in the system, but I am unable to locate where.

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  • Bug: unable to handle kernel NULL pointer dereference at

    - by maria
    I have recently installed new system on my disc, Ubuntu 12.04. Installation proceeded without problems, I started installing additional software and put data from other discs. I had already two times bug report, it was quite long, and I have no idea how to acces to log file (which probably is somewhere saved) and since I had to switch off the computer using the button, anything else was possible, here is just a small part of it (what I've noted on paper) could not write bytes: Broken pipe speach dicpatcher disabled: edit etc/default/speach-dispatcher saned disabled: edit .... and than: BUG: unable to handle kernel NULL pointer dereference at 0000009c I've run Memory test in GRUB, everything is fine. First time it occured when I was using rsync, second time when I was trying to install texlive. Should I install whole system once again? Or can it be hardware problem? Or something else? If there is any hardware details which may be relevant, please ask, since I have no idea what is happening, I don't know what kind of information could be useful. Thanks P.S. dmesg output:

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  • jQuery 1.4.4 - issue with attr('selected', null)

    - by Renso
    Issue: The code below worked before under version jQuery 1.4.2 but when I upgraded to version 1.4.4 it no longer worked as expected - it did not unselect the list box item, only setting "selectd" worked:         _handleClick: function(elem) {             var self = this; var initElem = this.element;             var checked = $(elem).attr('checked');             var myId = elem.attr('id').replace(initElem.attr('id') + '_chk_', '');             initElem.children('option[value=' + myId + ']').attr('selected', function() {                 if (checked) {                     return 'selected';                 } else { return null; }             });             if ($.isFunction(self.options.onItemSelected)) {                 try {                     self.options.onItemSelected(elem, initElem.children('option').get());                 } catch (ex) {                     if (self.options.allowDebug)                         alert('select function failed: ' + ex.Description);                 }             }         }, Solution: Under jQuery 1.4.4 you need to explicitly remove the attribute as in "removeAttr('selected'):         _handleClick: function(elem) {             var self = this; var initElem = this.element;             var checked = $(elem).is(':checked');             var myId = elem.attr('id').replace(initElem.attr('id') + '_chk_', '');             if (checked) {                 initElem.children('option[value=' + myId + ']').attr('selected', 'selected');             } else {                 initElem.children('option[value=' + myId + ']').removeAttr('selected');             }             if ($.isFunction(self.options.onItemSelected)) {                 try {                     self.options.onItemSelected(elem, initElem.children('option').get());                 } catch (ex) {                     if (self.options.allowDebug)                         alert('select function failed: ' + ex.Description);                 }             }         },

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  • zend tool is not working

    - by user362155
    Hi, I've installed ZendStudio 7.2 it creates project normally with no error but when i try to add action(s) in it, it says project profile does not exist. and the error log is as follow: executing zf create action showLatest index-action-included An Error Has Occurred A project profile was not found. Zend Framework Command Line Console Tool v1.10.2 Details for action "Create" and provider "Action" Action zf create action name controller-name[=Index] view-included[=1] module Failed loading ./ZendDebugger.so: (null) PHP Warning: PHP Startup: Unable to load dynamic library './ext/bcmath.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/bz2.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/calendar.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/ctype.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/curl.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/exif.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/fileinfo.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/ftp.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/gd.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/imagick.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/json.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/ldap.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/mbstring.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/mcrypt.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/memcache.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/mhash.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/mime_magic.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/mssql.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/mysql.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/mysqli.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/pcntl.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/pgsql.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/posix.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/shmop.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/soap.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/sockets.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/sqlite.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/sysvmsg.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/sysvsem.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/sysvshm.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/tidy.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/tokenizer.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/wddx.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/xmlreader.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/xmlrpc.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/xsl.so' - (null) in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library './ext/zip.so' - (null) in Unknown on line 0 please help me to configure latest ZendTool with ZendStudio 7.2 or how can i get rid of this. i am runin ZS 7.2 on my mac os x 10.5.8 thanks.

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  • C++ type-checking at compile-time

    - by Masterofpsi
    Hi, all. I'm pretty new to C++, and I'm writing a small library (mostly for my own projects) in C++. In the process of designing a type hierarchy, I've run into the problem of defining the assignment operator. I've taken the basic approach that was eventually reached in this article, which is that for every class MyClass in a hierarchy derived from a class Base you define two assignment operators like so: class MyClass: public Base { public: MyClass& operator =(MyClass const& rhs); virtual MyClass& operator =(Base const& rhs); }; // automatically gets defined, so we make it call the virtual function below MyClass& MyClass::operator =(MyClass const& rhs); { return (*this = static_cast<Base const&>(rhs)); } MyClass& MyClass::operator =(Base const& rhs); { assert(typeid(rhs) == typeid(*this)); // assigning to different types is a logical error MyClass const& casted_rhs = dynamic_cast<MyClass const&>(rhs); try { // allocate new variables Base::operator =(rhs); } catch(...) { // delete the allocated variables throw; } // assign to member variables } The part I'm concerned with is the assertion for type equality. Since I'm writing a library, where assertions will presumably be compiled out of the final result, this has led me to go with a scheme that looks more like this: class MyClass: public Base { public: operator =(MyClass const& rhs); // etc virtual inline MyClass& operator =(Base const& rhs) { assert(typeid(rhs) == typeid(*this)); return this->set(static_cast<Base const&>(rhs)); } private: MyClass& set(Base const& rhs); // same basic thing }; But I've been wondering if I could check the types at compile-time. I looked into Boost.TypeTraits, and I came close by doing BOOST_MPL_ASSERT((boost::is_same<BOOST_TYPEOF(*this), BOOST_TYPEOF(rhs)>));, but since rhs is declared as a reference to the parent class and not the derived class, it choked. Now that I think about it, my reasoning seems silly -- I was hoping that since the function was inline, it would be able to check the actual parameters themselves, but of course the preprocessor always gets run before the compiler. But I was wondering if anyone knew of any other way I could enforce this kind of check at compile-time.

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  • templates and casting operators

    - by Jonathan Swinney
    This code compiles in CodeGear 2009 and Visual Studio 2010 but not gcc. Why? class Foo { public: operator int() const; template <typename T> T get() const { return this->operator T(); } }; Foo::operator int() const { return 5; } The error message is: test.cpp: In member function `T Foo::get() const': test.cpp:6: error: 'const class Foo' has no member named 'operator T'

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  • Suppress Null Value Types from Being Emitted by XmlSerializer

    - by Ben Griswold
    Please consider the following Amount value type property which is marked as a nullable XmlElement: [XmlElement(IsNullable=true)] public double? Amount { get ; set ; } When a nullable value type is set to null, the C# XmlSerializer result looks like the following: <amount xsi:nil="true" /> Rather than emitting this element, I would like the XmlSerializer to suppress the element completely. Why? We're using Authorize.NET for online payments and Authorize.NET rejects the request if this null element exists. The current solution/workaround is to not serialize the Amount value type property at all. Instead we have created a complementary property, SerializableAmount, which is based on Amount and is serialized instead. Since SerializableAmount is of type String, which like reference types are suppressed by the XmlSerializer if null by default, everything works great. /// <summary> /// Gets or sets the amount. /// </summary> [XmlIgnore] public double? Amount { get; set; } /// <summary> /// Gets or sets the amount for serialization purposes only. /// This had to be done because setting value types to null /// does not prevent them from being included when a class /// is being serialized. When a nullable value type is set /// to null, such as with the Amount property, the result /// looks like: &gt;amount xsi:nil="true" /&lt; which will /// cause the Authorize.NET to reject the request. Strings /// when set to null will be removed as they are a /// reference type. /// </summary> [XmlElement("amount", IsNullable = false)] public string SerializableAmount { get { return this.Amount == null ? null : this.Amount.ToString(); } set { this.Amount = Convert.ToDouble(value); } } Of course, this is just a workaround. Is there a cleaner way to suppress null value type elements from being emitted?

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  • Explaining NULL and Empty to your 6-year old?

    - by Atomiton
    I'm thinking in terms of Objects here. I think it's important to simplify ideas. If you can explain this to a 6-year old, you can teach new programmers the difference. I'm thinking that a cookie object would be apropos: public class Cookie { public string flavor {get; set; } public int numberOfCrumbs { get; set; } }

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  • Filtering null values with pig

    - by arianp
    It looks like a silly problem, but I can´t find a way to filter null values from my rows. This is the result when I dump the object geoinfo: DUMP geoinfo; ([longitude#70.95853,latitude#30.9773]) ([longitude#-9.37944507,latitude#38.91780853]) (null) (null) (null) ([longitude#-92.64416,latitude#16.73326]) (null) (null) ([longitude#-9.15199849,latitude#38.71179122]) ([longitude#-9.15210796,latitude#38.71195131]) here is the description DESCRIBE geoinfo; geoinfo: {geoLocation: bytearray} What I'm trying to do is to filter null values like this: geoinfo_no_nulls = FILTER geoinfo BY geoLocation is not null; but the result remains the same. nothing is filtered. I also tried something like this geoinfo_no_nulls = FILTER geoinfo BY geoLocation != 'null'; and I got an error org.apache.pig.backend.executionengine.ExecException: ERROR 1071: Cannot convert a map to a String What am I doing wrong? details, running on ubuntu, hadoop-1.0.3 with pig 0.9.3 pig -version Apache Pig version 0.9.3-SNAPSHOT (rexported) compiled Oct 24 2012, 19:04:03 java version "1.6.0_24" OpenJDK Runtime Environment (IcedTea6 1.11.4) (6b24-1.11.4-1ubuntu0.12.04.1) OpenJDK 64-Bit Server VM (build 20.0-b12, mixed mode)

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  • "Invalid assignment" error from == operator

    - by Tom
    I was trying to write a simple method: boolean validate(MyObject o) { // propertyA && propertyB are not primitive types. return o.getPropertyA() == null && o.getPropertyB() == null; } And got a strange error on the == null part: Syntax error on token ==. Invalid assignment operator. Maybe my Java is rusty after a season in PLSQL. So I tried a simpler example: Integer i = 4; i == null; // compile error: Syntax error on token ==. Invalid assignment operator. Integer i2 = 4; if (i == null); //No problem How can this be? I'm using jdk160_05. To clarify: I'm not trying to assign anything, just do an && operation between two boolean values. I don't want to do this: if (o.propertyA() == null && o.propertyB() == null) { return true; } else { return false; }

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  • C# Automatic Properties - Still null after +=?

    - by Sam Schutte
    This seems like a bug to me... I accept that automatic properties, defined as such: public decimal? Total { get; set; } Will be null when they are first accessed. They haven't been initialized, so of course they are null. But, even after setting their value through +=, this decimal? still remains null. So after: Total += 8; Total is still null. How can this be correct? I understand that it's doing a (null + 8), but seems strange that it doesn't pick up that it means it should just be set to 8... Addendums: I made the "null + 8" point in my question - but notice that it works with strings. So, it does null + "hello" just fine, and returns "hello". Therefore, behind the scenes, it is initializing the string to a string object with the value of "hello". The behavior should be the same for the other types, IMO. It might be because a string can accept a null as a value, but still, a null string is not an initialized object, correct? Perhaps it's just because a string isn't a nullable...

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  • How do I go about overloading C++ operators to allow for chaining?

    - by fneep
    I, like so many programmers before me, am tearing my hair out writing the right-of-passage-matrix-class-in-C++. I have never done very serious operator overloading and this is causing issues. Essentially, by stepping through This is what I call to cause the problems. cMatrix Kev = CT::cMatrix::GetUnitMatrix(4, true); Kev *= 4.0f; cMatrix Baz = Kev; Kev = Kev+Baz; //HERE! What seems to be happening according to the debugger is that Kev and Baz are added but then the value is lost and when it comes to reassigning to Kev, the memory is just its default dodgy values. How do I overload my operators to allow for this statement? My (stripped down) code is below. //header class cMatrix { private: float* _internal; UInt32 _r; UInt32 _c; bool _zeroindexed; //fast, assumes zero index, no safety checks float cMatrix::_getelement(UInt32 r, UInt32 c) { return _internal[(r*this->_c)+c]; } void cMatrix::_setelement(UInt32 r, UInt32 c, float Value) { _internal[(r*this->_c)+c] = Value; } public: cMatrix(UInt32 r, UInt32 c, bool IsZeroIndexed); cMatrix( cMatrix& m); ~cMatrix(void); //operators cMatrix& operator + (cMatrix m); cMatrix& operator += (cMatrix m); cMatrix& operator = (const cMatrix &m); }; //stripped source file cMatrix::cMatrix(cMatrix& m) { _r = m._r; _c = m._c; _zeroindexed = m._zeroindexed; _internal = new float[_r*_c]; UInt32 size = GetElementCount(); for (UInt32 i = 0; i < size; i++) { _internal[i] = m._internal[i]; } } cMatrix::~cMatrix(void) { delete[] _internal; } cMatrix& cMatrix::operator+(cMatrix m) { return cMatrix(*this) += m; } cMatrix& cMatrix::operator*(float f) { return cMatrix(*this) *= f; } cMatrix& cMatrix::operator*=(float f) { UInt32 size = GetElementCount(); for (UInt32 i = 0; i < size; i++) { _internal[i] *= f; } return *this; } cMatrix& cMatrix::operator+=(cMatrix m) { if (_c != m._c || _r != m._r) { throw new cCTException("Cannot add two matrix classes of different sizes."); } if (!(_zeroindexed && m._zeroindexed)) { throw new cCTException("Zero-Indexed mismatch."); } for (UInt32 row = 0; row < _r; row++) { for (UInt32 column = 0; column < _c; column++) { float Current = _getelement(row, column) + m._getelement(row, column); _setelement(row, column, Current); } } return *this; } cMatrix& cMatrix::operator=(const cMatrix &m) { if (this != &m) { _r = m._r; _c = m._c; _zeroindexed = m._zeroindexed; delete[] _internal; _internal = new float[_r*_c]; UInt32 size = GetElementCount(); for (UInt32 i = 0; i < size; i++) { _internal[i] = m._internal[i]; } } return *this; }

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  • Overloading stream insertion without violating information hiding?

    - by Chris
    I'm using yaml-cpp for a project. I want to overload the << and >> operators for some classes, but I'm having an issue grappling with how to "properly" do this. Take the Note class, for example. It's fairly boring: class Note { public: // constructors Note( void ); ~Note( void ); // public accessor methods void number( const unsigned long& number ) { _number = number; } unsigned long number( void ) const { return _number; } void author( const unsigned long& author ) { _author = author; } unsigned long author( void ) const { return _author; } void subject( const std::string& subject ) { _subject = subject; } std::string subject( void ) const { return _subject; } void body( const std::string& body ) { _body = body; } std::string body( void ) const { return _body; } private: unsigned long _number; unsigned long _author; std::string _subject; std::string _body; }; The << operator is easy sauce. In the .h: YAML::Emitter& operator << ( YAML::Emitter& out, const Note& v ); And in the .cpp: YAML::Emitter& operator << ( YAML::Emitter& out, const Note& v ) { out << v.number() << v.author() << v.subject() << v.body(); return out; } No sweat. Then I go to declare the >> operator. In the .h: void operator >> ( const YAML::Node& node, Note& note ); But in the .cpp I get: void operator >> ( const YAML::Node& node, Note& note ) { node[0] >> ? node[1] >> ? node[2] >> ? node[3] >> ? return; } If I write things like node[0] >> v._number; then I would need to change the CV-qualifier to make all of the Note fields public (which defeats everything I was taught (by professors, books, and experience))) about data hiding. I feel like doing node[0] >> temp0; v.number( temp0 ); all over the place is not only tedious, error-prone, and ugly, but rather wasteful (what with the extra copies). Then I got wise: I attempted to move these two operators into the Note class itself, and declare them as friends, but the compiler (GCC 4.4) didn't like that: src/note.h:44: error: ‘YAML::Emitter& Note::operator<<(YAML::Emitter&, const Note&)’ must take exactly one argument src/note.h:45: error: ‘void Note::operator(const YAML::Node&, Note&)’ must take exactly one argument Question: How do I "properly" overload the >> operator for a class Without violating the information hiding principle? Without excessive copying?

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  • Overloading '-' for array subtraction

    - by Chris Wilson
    I am attempting to subtract two int arrays, stored as class members, using an overloaded - operator, but I'm getting some peculiar output when I run tests. The overload definition is Number& Number :: operator-(const Number& NumberObject) { for (int count = 0; count < NumberSize; count ++) { Value[count] -= NumberObject.Value[count]; } return *this; } Whenever I run tests on this, NumberObject.Value[count] always seems to be returning a zero value. Can anyone see where I'm going wrong with this? The line in main() where this subtraction is being carried out is cout << "The difference is: " << ArrayOfNumbers[0] - ArrayOfNumbers[1] << endl; ArrayOfNumbers contains two Number objects. The class declaration is #include <iostream> using namespace std; class Number { private: int Value[50]; int NumberSize; public: Number(); // Default constructor Number(const Number&); // Copy constructor Number(int, int); // Non-default constructor void SetMemberValues(int, int); // Manually set member values int GetNumberSize() const; // Return NumberSize member int GetValue() const; // Return Value[] member Number& operator-=(const Number&); }; inline Number operator-(Number Lhs, const Number& Rhs); ostream& operator<<(ostream&, const Number&); The full class definition is as follows: #include <iostream> #include "../headers/number.h" using namespace std; // Default constructor Number :: Number() {} // Copy constructor Number :: Number(const Number& NumberObject) { int Temp[NumberSize]; NumberSize = NumberObject.GetNumberSize(); for (int count = 0; count < NumberObject.GetNumberSize(); count ++) { Temp[count] = Value[count] - NumberObject.GetValue(); } } // Manually set member values void Number :: SetMemberValues(int NewNumberValue, int NewNumberSize) { NumberSize = NewNumberSize; for (int count = NewNumberSize - 1; count >= 0; count --) { Value[count] = NewNumberValue % 10; NewNumberValue = NewNumberValue / 10; } } // Non-default constructor Number :: Number(int NumberValue, int NewNumberSize) { NumberSize = NewNumberSize; for (int count = NewNumberSize - 1; count >= 0; count --) { Value[count] = NumberValue % 10; NumberValue = NumberValue / 10; } } // Return the NumberSize member int Number :: GetNumberSize() const { return NumberSize; } // Return the Value[] member int Number :: GetValue() const { int ResultSoFar; for (int count2 = 0; count2 < NumberSize; count2 ++) { ResultSoFar = ResultSoFar * 10 + Value[count2]; } return ResultSoFar; } Number& operator-=(const Number& Rhs) { for (int count = 0; count < NumberSize; count ++) { Value[count] -= Rhs.Value[count]; } return *this; } inline Number operator-(Number Lhs, const Number& Rhs) { Lhs -= Rhs; return Lhs; } // Overloaded output operator ostream& operator<<(ostream& OutputStream, const Number& NumberObject) { OutputStream << NumberObject.GetValue(); return OutputStream; }

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  • (NOT) NULL for NVARCHAR columns

    - by Anders Abel
    Allowing NULL values on a column is normally done to allow the absense of a value to be represented. When using NVARCHAR there is aldready a possibility to have an empty string, without setting the column to NULL. In most cases I cannot see a semantical difference between an NVARCHAR with an empty string and a NULL value for such a column. Setting the column as NOT NULL saves me from having to deal with the possibility of NULL values in the code and it feels better to not have to different representations of "no value" (NULL or an empty string). Will I run into any other problems by setting my NVARCHAR columns to NOT NULL. Performance? Storage size? Anything I've overlooked on the usage of the values in the client code?

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  • SQL Server JOIN with optional NULL values

    - by Paul McLoughlin
    Imagine that we have two tables as follows: Trades ( TradeRef INT NOT NULL, TradeStatus INT NOT NULL, Broker INT NOT NULL, Country VARCHAR(3) NOT NULL ) CTMBroker ( Broker INT NOT NULL, Country VARCHAR(3) NULL ) (These have been simplified for the purpose of this example). Now, if we wish to join these two tables on the Broker column, and if a country exists in the CTMBroker table on the Country, we have the following two choices: SELECT T.TradeRef,T.TradeStatus FROM Trades AS T JOIN CTMBroker AS B ON B.Broker=T.Broker AND ISNULL(B.Country, T.Country) = T.Country or SELECT T.TradeRef,T.TradeStatus FROM Trades AS T JOIN CTMBroker AS B ON B.Broker=T.Broker AND (B.COUNTRY=T.Country OR B.Country IS NULL) These are both logically equivalent, however in this specific circumstance for our database (SQL Server 2008, SP1) two different execution plans are produced for these two queries with the second version significantly outperforming the first version in terms of both time and logical reads. My question really is as follows: as a general rule would (2) be preferred to (1), or does this just happen to be exploiting some particular idiosyncracy of the optimiser in 2008 SP1 (that could therefore change with future versions of SQL Server).

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