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• Panel in Windows Forms Application not clearing

  - by SwiftStriker00

  I'm working on my project: [Beer Pong Management System][1], a Windows Forms application. I am currently trying to add a whole tournament mode to it. In a nutshell, I've created a TabControl, with the first tab page with the settings and setup and the second page the brackets. There is a feature for each of the match-ups, that once there is a winner is decided, a yellow cancel button will appear in order to revert the tournament. However my issue is when i click the button the next match-up does not get removed in the series is going. See below: Image Here(not high enough rep to insert image) I have tried to set the MatchUp to null, I've tried dispose(), close(). even Parent.Controls.Remove(). Even after I switch tabs which is supposed to clear all, they still sit there when i come back. I have a feeling I might be loosing a reference or something because I can't even push new teams into them, they just sit there with their buttons. Does anyone have any tips or know of any known issues that might be causing this? Thanks. [1] _http://www.cs.rit.edu/~rmb1201/pages/code.shtml

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• switch namespace by if condtion

  - by pascal

  Hi, in my C++ program I have several namespaces that contain several pointers with identical names. I then want a function to choose a namespace according to a parameter. I.e. something like: #include <iostream> namespace ns1{ double x[5]={1,2,3,4,5}; } namespace ns2{ double x[5]={6,7,8,9,10}; } int main(){ int b=1; if(b==1){ using namespace ns1; } if(b==2){ using namespace ns2; } std::cout << x[3] << std::endl; } However, this doesn't work since the compiler complains that x isn't known in that scope. I guess the problem is that "using namespace ..." is only valid within the if-statement. I think that it should be possible to switch namespaces somehow, but cannot find out how... Do you know how to do this without casting all variable separately? int main(){ int b=1; double *x; if(b==1){ x = ns1::x; } if(b==2){ x = ns2::x; } std::cout << x[3] << std::endl; } Cheers, Pascal

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• Any workarounds for non-static member array initialization?

  - by TomiJ

  In C++, it's not possible to initialize array members in the initialization list, thus member objects should have default constructors and they should be properly initialized in the constructor. Is there any (reasonable) workaround for this apart from not using arrays? [Anything that can be initialized using only the initialization list is in our application far preferable to using the constructor, as that data can be allocated and initialized by the compiler and linker, and every CPU clock cycle counts, even before main. However, it is not always possible to have a default constructor for every class, and besides, reinitializing the data again in the constructor rather defeats the purpose anyway.] E.g. I'd like to have something like this (but this one doesn't work): class OtherClass { private: int data; public: OtherClass(int i) : data(i) {}; // No default constructor! }; class Foo { private: OtherClass inst[3]; // Array size fixed and known ahead of time. public: Foo(...) : inst[0](0), inst[1](1), inst[2](2) {}; }; The only workaround I'm aware of is the non-array one: class Foo { private: OtherClass inst0; OtherClass inst1; OtherClass inst2; OtherClass *inst[3]; public: Foo(...) : inst0(0), inst1(1), inst2(2) { inst[0]=&inst0; inst[1]=&inst1; inst[2]=&inst2; }; }; Edit: It should be stressed that OtherClass has no default constructor, and that it is very desirable to have the linker be able to allocate any memory needed (one or more static instances of Foo will be created), using the heap is essentially verboten. I've updated the examples above to highlight the first point.

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• Why "Content-Length: 0" in POST requests?

  - by stesch

  A customer sometimes sends POST requests with Content-Length: 0 when submitting a form (10 to over 40 fields). We tested it with different browsers and from different locations but couldn't reproduce the error. The customer is using Internet Explorer 7 and a proxy. We asked them to let their system administrator see into the problem from their side. Running some tests without the proxy, etc.. In the meantime (half a year later and still no answer) I'm curious if somebody else knows of similar problems with a Content-Length: 0 request. Maybe from inside some Windows network with a special proxy for big companies. Is there a known problem with Internet Explorer 7? With a proxy system? The Windows network itself? Google only showed something in the context of NTLM (and such) authentication, but we aren't using this in the web application. Maybe it's in the way the proxy operates in the customer's network with Windows logins? (I'm no Windows expert. Just guessing.) I have no further information about the infrastructure.

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• What do I do about a Java program that spawned two instaces of itself?

  - by user288915

  I have a java JAR file that is triggered by a SQL server job. It's been running successfully for months. The process pulls in a structured flat file to a staging database then pushes that data into an XML file. However yesterday the process was triggered twice at the same time. I can tell from a log file that gets created, it looks like the process ran twice simultaneously. This caused a lot of issues and the XML file that it kicked out was malformed and contained duplicate nodes etc. My question is, is this a known issue with Java JVM's spawning multiple instances of itself? Or should I be looking at sql server as the culprit? I'm looking into 'socket locking' or file locking to prevent multiple instances in the future. This is the first instance of this issue that I've ever heard of. More info: The job is scheduled to run every minute. The job triggers a .bat file that contains the java.exe - jar filename.jar The java program runs, scans a directory for a file and then executes a loop to process if the file if it finds one. After it processes the file it runs another loop that kicks out XML messages. I can provide code samples if that would help. Thank you, Kevin

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• Configuration Error , Finding assembly after I swapped referenced dll out. Visual Studio 2003

  - by TampaRich

  Here is the situation. I had a clean build of my asp.net web application working. I then went into the bin folder under the web app and replaced two referenced dll's with two older version of the same dll's. (Same name etc.) After testing I replaced those dll's back to the new ones and now my application keeps throwing the configuration error === Pre-bind state information === LOG: DisplayName = xxxxx.xxxx.Personalization (Partial) LOG: Appbase = file:///c:/inetpub/wwwroot/appname LOG: Initial PrivatePath = bin Calling assembly : (Unknown). LOG: Policy not being applied to reference at this time (private, custom, partial, or location-based assembly bind). I found this issue on the web and tried all the solutions to it but nothing worked. I then went into all my projects that it references under the solution and cleared out the bin/debug folder in each, I cleared out the obj folder under each and also deleted the temporary files associated with the application. I rebuilt it and it still will not work due to this error Not sure what is causing this or how to fix this issue. I have tried restarting IIS, stopping index services which was said to be a known issue. This is .net framework 1.1 app and visual studio 2003 Any suggestions would be great. Thanks.

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• Reference remotely located assembly (web uri) from locally installed application?

  - by moonground.de

  Hi Stackoverflowers! :) We have a .NET application for Windows which is installed locally by Microsoft Installer. Now we have the need to use additional assemblies which are located online at our Web Servers. We'd like to refer to a remote uri like https://www.ourserver.com/OurProductName/ExternalLib.dll and reveal additional functionality, which is described roughly by a known common ("AddIn/Plugin") Interface. These are not 3rd Party Plugins, we just want be able to exchange parts of the application frequently, without the need to have frequent software updates. Our first idea was to add some kind of "remote refence" in Visual Studio by setting the path to the remote assembly uri. But Visual Studio downloaded the assembly immediately to a temporary directory, adding a reference to it. Our second attempt then, is simply using a WebRequest (or WebClient) to retrieve a binary stream of the Assembly, loading it "from image" by using Assembly.Load(...). This actually works, but is not very elegant and requires more additional programming for verification etc. We hoped Clickonce would provide useful techniques but apparently it's suitable for standalone applications only. (Correct me?) Is there a way (.net native or by framework/api) to reference remotely located assemblies? Thanks in advance and have a happy easter!

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• Cryptography for P2P card game

  - by zephyr

  I'm considering writing a computer adaptation of a semi-popular card game. I'd like to make it function without a central server, and I'm trying to come up with a scheme that will make cheating impossible without having to trust the client. The basic problem as I see it is that each player has a several piles of cards (draw deck, current hand and discard deck). It must be impossible for either player to alter the composition of these piles except when allowed by the game rules (ie drawing or discarding cards), nor should players be able to know what is in their or their oppponent's piles. I feel like there should be some way to use something like public-key cryptography to accomplish this, but I keep finding holes in my schemes. Can anyone suggest a protocol or point me to some resources on this topic? [Edit] Ok, so I've been thinking about this a bit more, and here's an idea I've come up with. If you can poke any holes in it please let me know. At shuffle time, a player has a stack of cards whose value is known to them. They take these values, concatenate a random salt to each, then hash them. They record the salts, and pass the hashes to their opponent. The opponent concatenates a salt of their own, hashes again, then shuffles the hashes and passes the deck back to the original player. I believe at this point, the deck has been randomized and neither player can have any knowledge of the values. However, when a card is drawn, the opponent can reveal their salt, allowing the first player to determine what the original value is, and when the card is played the player reveals their own salt, allowing the opponent to verify the card value.

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• Pass the return type as a parameter in java?

  - by jonderry

  I have some files that contain logs of objects. Each file can store objects of a different type, but a single file is homogeneous -- it only stores objects of a single type. I would like to write a method that returns an array of these objects, and have the array be of a specified type (the type of objects in a file is known and can be passed as a parameter). Roughly, what I want is something like the following: public static <T> T[] parseLog(File log, Class<T> cls) throws Exception { ArrayList<T> objList = new ArrayList<T>(); FileInputStream fis = new FileInputStream(log); ObjectInputStream in = new ObjectInputStream(fis); try { Object obj; while (!((obj = in.readObject()) instanceof EOFObject)) { T tobj = (T) obj; objList.add(tobj); } } finally { in.close(); } return objList.toArray(new T[0]); } The above code doesn't compile (there's an error on the return statement, and a warning on the cast), but it should give you the idea of what I'm trying to do. Any suggestions for the best way to do this?

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• Echo a multidimensional array in PHP

  - by Jennifer

  I have a multidimensional array and I'm trying to find out how to simply "echo" the elements of the array. The depth of the array is not known, so it could be deeply nested. In the case of the array below, the right order to echo would be: This is a parent comment This is a child comment This is the 2nd child comment This is another parent comment This is the array I was talking about: Array ( [0] => Array ( [comment_id] => 1 [comment_content] => This is a parent comment [child] => Array ( [0] => Array ( [comment_id] => 3 [comment_content] => This is a child comment [child] => Array ( [0] => Array ( [comment_id] => 4 [comment_content] => This is the 2nd child comment [child] => Array ( ) ) ) ) ) ) [1] => Array ( [comment_id] => 2 [comment_content] => This is another parent comment [child] => Array ( ) ) )

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• jquery simplemodal close wont work in firefox

  - by junkqwe

  I am using jquery.simplemodal 1.3.5 (i tried older versions) the close button doesnt close the modal in firefox (i tried IE and it work fine) this is the test page i am using: <html> <head> <title>Untitled Page</title> <style> #simplemodal-overlay { background-color:#000; cursor:wait; } #simplemodal-container a.modalCloseImg { background: url(../images/modal_close.png) no-repeat; width:25px; height:29px; display:inline; z-index:3200; position:absolute; top:15px; right:18px; cursor:pointer; } .modala { width: 372px; height: 206px; background: url(../images/modal.png) no-repeat; } </style> </head> <body> test page <script language="javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js" type="text/javascript"></script> <script language="javascript" src="/include/jquery.simplemodal-1.3.5.js" type="text/javascript"></script> <script type="text/javascript"> $("body").click(function() { $.modal("<div class=\"modala\"><h1>SimpleModal</h1></div>", {overlayClose: true} ); }); </script> </body> </html> what can be the problem? is it a known problem with simplemodal and FF?

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• C#/DataSet: Create and bind a custom column/property in a DataSet`s DataTable in the XXXDataSet.cs

  - by msfanboy

  Hello, I have a DataSet with a DataTable having the columns Number and Description. I do not want to bind both properties to a BindingSource bound again to 2 controls. What I want is a 3rd column in the DataTable called NumberDescription which is a composition of Number and Description. This property is bound only to 1 control/BindingSource`s property not 2. There is the partial XXXDataSet.Designer.cs file and the partial XXXDataSet.cs file. Of course I have defined the public string NumberDescription {get (doing some checks here;set (doing also some checks here} in the XXXDataSet.cs file. But all this does not bind my new property/Column to the BindingSource the DataTable is bound to because the DataSet does not know the new column/property. To make this new property/column known I could add a new column to the DataTAble in the DataSet designer view naming it NumberDescription. At least I see know the new property in the listing of the BindingSource so I can choose it. But all that did not help?? So how do I do that stuff properly? Should I call the NumberDescription Property in the Number AND Description Property ?

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• What's a good way to organize a large collection of personal scripts using git?

  - by spooky note

  I have a large collection of my personal scripts that I would like to start versioning using Git. I've previously organized my code as follows: ~/code/python/projects/ (for large stuff, each project contained in an individual folder) ~/code/python/scripts/ (single file scripts all contained in this directory) ~/code/python/sandbox/ (my testing area) ~/code/python/docs/ (downloaded documentation) ~/code/java/... (as above) Now i'm going to start versioning my code using git, so that I can have history and backup all my code to a remote server. I know if I were using SVN I would just keep my entire "~/code/" directory in a large repository, but I understand this is not a good way to do things with Git. Most info I've seen online suggests keeping all my project folders in a single place (as in, no separate directories for python or java) with each project containing it's own git repository, and simply having a "snippets" directory containing all single-file scripts/experiments that can be converted into projects at a later date. But I'm not sure how I feel about consolidating all of my code directories into one area. Is there a good way to keep my separate code directories intact, or is it not worth the effort? Maybe I'm just attached to the separate code directories because I've never known anything else... Also (as a side note), I'd like to quickly be able to see a chronological history of all my projects and scripts. So I can see which projects I created most recently. I used to do this by keeping a number at the beginning of all my projects, 002project, 003project. Is there automatic or easy way to do this in git without having to add a number to all of the project names? I'm open to any practical or philosophical code organizing advice you have. Thanks!!!

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• How to combine two rows and calculate the time difference between two timestamp values in MySQL?

  - by Nadar

  I have a situation that I'm sure is quite common and it's really bothering me that I can't figure out how to do it or what to search for to find a relevant example/solution. I'm relatively new to MySQL (have been using MSSQL and PostgreSQL earlier) and every approach I can think of is blocked by some feature lacking in MySQL. I have a "log" table that simply lists many different events with their timestamp (stored as datetime type). There's lots of data and columns in the table not relevant to this problem, so lets say we have a simple table like this: CREATE TABLE log ( id INT NOT NULL AUTO_INCREMENT, name VARCHAR(16), ts DATETIME NOT NULL, eventtype VARCHAR(25), PRIMARY KEY (id) ) Let's say that some rows have an eventtype = 'start' and others have an eventtype = 'stop'. What I want to do is to somehow couple each "startrow" with each "stoprow" and find the time difference between the two (and then sum the durations per each name, but that's not where the problem lies). Each "start" event should have a corresponding "stop" event occuring at some stage later then the "start" event, but because of problems/bugs/crashed with the data collector it could be that some are missing. In that case I would like to disregard the event without a "partner". That means that given the data: foo, 2010-06-10 19:45, start foo, 2010-06-10 19:47, start foo, 2010-06-10 20:13, stop ..I would like to just disregard the 19:45 start event and not just get two result rows both using the 20:13 stop event as the stop time. I've tried to join the table with itself in different ways, but the key problems for me seems to be to find a way to correctly identify the corresponding "stop" event to the "start" event for the given "name". The problem is exactly the same as you would have if you had table with employees stamping in and out of work and wanted to find out how much they actually were at work. I'm sure there must be well known solutions to this, but I can't seem to find them...

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• Storing C++ templated objects as same type

  - by JaredC

  I have a class that is a core component of a performance sensitive code path, so I am trying to optimize it as much as possible. The class used to be: class Widget { Widget(int n) : N(n) {} .... member functions that use the constant value N .... const int N; // just initialized, will never change } The arguments to the constructor are known at compile time, so I have changed this class to a template, so that N can be compiled into the functions: template<int N> class Widget { .... member functions that use N .... } I have another class with a method: Widget & GetWidget(int index); However, after templating Widget, each widget has a different type so I cannot define the function like this anymore. I considered different inheritance options, but I'm not sure that the performance gain from the template would outweigh the cost of inherited function invocations. SO, my question is this: I am pretty sure I want the best of both worlds (compile-time / run-time), and it may not be possible. But, is there a way to gain the performance of knowing N at compile time, but still being able to return Widgets as the same type? Thanks!

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• Automate Field Entry in outside site

  - by JClaspill

  I am attempting to automate the entry of data into form fields. The problem is that this data (user/pass) is not known by the user. I'm not expressly hiding it from them, but they also don't need to know it. This is used to automate logins on several of our outside partner websites, who do not want our agents knowing their passwords. Sadly, most of these sites do not have any APIs I can work with... so I have to get the user logged in. I tried using an iframe and javascript, but I ran into the issue of security permissions denying it access. And sadly, our clients do not have access to add our domain to their sites(they seem to be 3rd party). Requirements: - Display webpage - Automatically enter data into fields Would be nice: - Automate signin similar to form.submit() - Flash/AJAX support. These seem to give the VB app issues. Is there a way to do this via javascript/html, and if not, do you have any recommendations for C#/php/asp.net options? PS: I am not sure what this techinque is called, so google isn't helping me it seems. Please set me straight on the terminology of what I am actually trying to accomplish.

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• Use LINQ, to Sort and Filter items in a List<ReturnItem> collection, based on the values within a Li

  - by Daniel McPherson

  This is tricky to explain. We have a DataTable that contains a user configurable selection of columns, which are not known at compile time. Every column in the DataTable is of type String. We need to convert this DataTable into a strongly typed Collection of "ReturnItem" objects so that we can then sort and filter using LINQ for use in our application. We have made some progress as follows: We started with the basic DataTable. We then process the DataTable, creating a new "ReturnItem" object for each row This "ReturnItem" object has just two properties: ID ( string ) and Columns( List(object) ). The properties collection contains one entry for each column, representing a single DataRow. Each property is made Strongly Typed (int, string, datetime, etc). For example it would add a new "DateTime" object to the "ReturnItem" Columns List containing the value of the "Created" Datatable Column. The result is a List(ReturnItem) that we would then like to be able to Sort and Filter using LINQ based on the value in one of the properties, for example, sort on "Created" date. We have been using the LINQ Dynamic Query Library, which gets us so far, but it doesn't look like the way forward because we are using it over a List Collection of objects. Basically, my question boils down to: How can I use LINQ, to Sort and Filter items in a List(ReturnItem) collection, based on the values within a List(object) property which is part of the ReturnItem class?

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• Why won't my code segfault on Windows 7?

  - by Trevor

  This is an unusual question to ask but here goes: In my code, I accidentally dereference NULL somewhere. But instead of the application crashing with a segfault, it seems to stop execution of the current function and just return control back to the UI. This makes debugging difficult because I would normally like to be alerted to the crash so I can attach a debugger. What could be causing this? Specifically, my code is an ODBC Driver (ie. a DLL). My test application is ODBC Test (odbct32w.exe) which allows me to explicitly call the ODBC API functions in my DLL. When I call one of the functions which has a known segfault, instead of crashing the application, ODBC Test simply returns control to the UI without printing the result of the function call. I can then call any function in my driver again. I do know that technically the application calls the ODBC driver manager which loads and calls the functions in my driver. But that is beside the point as my segfault (or whatever is happening) causes the driver manager function to not return either (as evidenced by the application not printing a result). One of my co-workers with a similar machine experiences this same problem while another does not but we have not been able to determine any specific differences.

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• What does the Asterisk * mean in Objective-C?

  - by Thanks

  Is it true, that the Asterisk always means "Hey, that is a pointer!" And an Pointer always holds an memory adress? (Yes I know for the exception that a * is used for math operation) For Example: NSString* myString; or SomeClass* thatClass; or (*somePointerToAStruct).myStructComponent = 5; I feel that there is more I need to know about the Asterirsk (*) than that I use it when defining an Variable that is a pointer to a class. Because sometimes I already say in the declaration of an parameter that the Parameter variable is a pointer, and still I have to use the Asterisk in front of the Variable in order to access the value. That recently happened after I wanted to pass a pointer of an struct to a method in a way like [myObj myMethod:&myStruct], I could not access a component value from that structure even though my method declaration already said that there is a parameter (DemoStruct*)myVar which indeed should be already known as a pointer to that demostruct, still I had always to say: "Man, compiler. Listen! It IIISSS a pointer:" and write: (*myVar).myStructComponentX = 5; I really really really do not understand why I have to say that twice. And only in this case. When I use the Asterisk in context of an NSString* myString then I can just access myString however I like, without telling the compiler each time that it's a pointer. i.e. like using *myString = @"yep". It just makes no sense to me.

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• Has inheritance become bad?

  - by mafutrct

  Personally, I think inheritance is a great tool, that, when applied reasonably, can greatly simplify code. However, I seems to me that many modern tools dislike inheritance. Let's take a simple example: Serialize a class to XML. As soon as inheritance is involved, this can easily turn into a mess. Especially if you're trying to serialize a derived class using the base class serializer. Sure, we can work around that. Something like a KnownType attribute and stuff. Besides being an itch in your code that you have to remember to update every time you add a derived class, that fails, too, if you receive a class from outside your scope that was not known at compile time. (Okay, in some cases you can still work around that, for instance using the NetDataContract serializer in .NET. Surely a certain advancement.) In any case, the basic principle still exists: Serialization and inheritance don't mix well. Considering the huge list of programming strategies that became possible and even common in the past decade, I feel tempted to say that inheritance should be avoided in areas that relate to serialization (in particular remoting and databases). Does that make sense? Or am messing things up? How do you handle inheritance and serialization?

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• ServiceLoader double iterator issues

  - by buge

  Is this a known issue? I had trouble finding any search results. When iterating over a ServiceLoader while an iteration already is in progress, the first iteration will be aborted. For example, assuming there are at least two implementations of Foo, the following code will fail with an AssertionError: ServiceLoader<Foo> loader = ServiceLoader.load(Foo.class); Iterator<Foo> iter1 = loader.iterator(); iter1.next(); Iterator<Foo> iter2 = loader.iterator(); while (iter2.hasNext()) { iter2.next(); } assert iter1.hasNext(); This only seems to occur, if the second iterator really terminates. The code will succeed in this variation for example: ServiceLoader<Foo> loader = ServiceLoader.load(Foo.class); Iterator<Foo> iter1 = loader.iterator(); iter1.next(); Iterator<Foo> iter2 = loader.iterator(); iter2.next(); assert iter1.hasNext(); Is this a bug or a feature? :p Is there a ticket for this already anywhere?

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• Querying for a unique value based on the aggregate of another value while grouping on a third value

  - by Justin Swartsel

  So I know this problem isn't a new one, but I'm trying to wrap my head around it and understand the best way to deal with scenarios like this. Say I have a hypothetical table 'X' that looks like this: GroupID ID (identity) SomeDateTime -------------------------------------------- 1 1000 1/1/01 1 1001 2/2/02 1 1002 3/3/03 2 1003 4/4/04 2 1004 5/5/05 I want to query it so the result set looks like this: ---------------------------------------- 1 1002 3/3/03 2 1004 5/5/05 Basically what I want is the MAX SomeDateTime value grouped by my GroupID column. The kicker is that I DON'T want to group by the ID column, I just want to know the 'ID' that corresponds to the MAX SomeDateTime. I know one pseudo-solution would be: ;WITH X1 as ( SELECT MAX(SomeDateTime) as SomeDateTime, GroupID FROM X GROUP BY GroupID ) SELECT X1.SomeDateTime, X1.GroupID, X2.ID FROM X1 INNER JOIN X as X2 ON X.DateTime = X2.DateTime But this doesn't solve the fact that a DateTime might not be unique. And it seems sloppy to join on a DateTime like that. Another pseudo-solution could be: SELECT X.GroupID, MAX(X.ID) as ID, MAX(X.SomeDateTime) as SomeDateTime FROM X GROUP BY X.GroupID But there are no guarantees that ID will actually match the row that SomeDateTime comes from. A third less useful option might be: SELECT TOP 1 X.GroupID, X.ID, X.SomeDateTime FROM X WHERE X.GroupID = 1 ORDER BY X.SomeDateTime DESC But obviously that only works with a single, known, GroupID. I want to be able to join this result set on GroupID and/or ID. Does anyone know of any clever solutions? Any good uses of windowing functions? Thanks!

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• Is inheritance bad nowadays?

  - by mafutrct

  Personally, I think inheritance is a great tool, that, when applied reasonably, can greatly simplify code. However, I seems to me that many modern tools dislike inheritance. Let's take a simple example: Serialize a class to XML. As soon as inheritance is involved, this can easily turn into a mess. Especially if you're trying to serialize a derived class using the base class serializer. Sure, we can work around that. Something like a KnownType attribute and stuff. Besides being an itch in your code that you have to remember to update every time you add a derived class, that fails, too, if you receive a class from outside your scope that was not known at compile time. (Okay, in some cases you can still work around that, for instance using the NetDataContract serializer in .NET. Surely a certain advancement.) In any case, the basic principle still exists: Serialization and inheritance don't mix well. Considering the huge list of programming strategies that became possible and even common in the past decade, I feel tempted to say that inheritance should be avoided in areas that relate to serialization (in particular remoting and databases). Does that make sense? Or am messing things up? How do you handle inheritance and serialization?

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• Graph search problem with route restrictions

  - by Darcara

  I want to calculate the most profitable route and I think this is a type of traveling salesman problem. I have a set of nodes that I can visit and a function to calculate cost for traveling between nodes and points for reaching the nodes. The goal is to reach a fixed known score while minimizing the cost. This cost and rewards are not fixed and depend on the nodes visited before. The starting node is fixed. There are some restrictions on how nodes can be visited. Some simplified examples include: Node B can only be visited after A After node C has been visited, D or E can be visited. Visiting at least one is required, visiting both is permissible. Z can only be visited after at least 5 other nodes have been visited Once 50 nodes have been visited, the nodes A-M will no longer reward points Certain nodes can (and probably must) be visited multiple times Currently I can think of only two ways to solve this: a) Genetic Algorithms, with the fitness function calculating the cost/benefit of the generated route b) Dijkstra search through the graph, since the starting node is fixed, although the large number of nodes will probably make that not feasible memory wise. Are there any other ways to determine the best route through the graph? It doesn't need to be perfect, an approximated path is perfectly fine, as long as it's error acceptable. Would TSP-solvers be an option here?

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• Is there a way to identify that a file has been modified and moved?

  - by Eric

  I'm writing an application that catalogs files, and attributes them with extra meta data through separate "side-car" files. If changes to the files are made through my program then it is able to keep everything in sync between them and their corresponding meta data files. However, I'm trying to figure out a way to deal with someone modifying the files manually while my program is not running. When my program starts up it scans the file system and compares the files it finds to it's previous record of what files it remembers being there. It's fairly straight forward to update after a file has been deleted or added. However, if a file was moved or renamed then my program sees that as the old file being deleted, and the new file being added. Yet I don't want to loose the association between the file and its metadata. I was thinking I could store a hash from each file so I could check to see if newly found files were really previously known files that had been moved or renamed. However, if the file is both moved/renamed and modified then the hash would not match either. So is there some other unique identifier of a file that I can track which stays with it even after it is renamed, moved, or modified?

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