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• Change Large Number of Record Keys using Map Table

  - by Coyote

  I have a set of records indexed by id numbers, I need to convert these record's indexes to a new id number. I have a two column table mapping the old numbers to the new numbers. For example given these two tables, what would the update statement look like? Given: OLD_TO_NEW oldid | newid ----------------- 1234 0987 7698 5645 ... ... and id | data ---------------- 1234 'yo' 7698 'hey' ... ... Need: id | data ---------------- 0987 'yo' 5645 'hey' ... ... This oracle so I have access to PL/SQL, I'm just trying to avoid it.

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• Model Binding an IList of selected items only

  - by jeef3

  I have an action method setup: public ActionResult Delete(IList<Product> products) And a table of products in my view. I have got Model Binding working so that on submit I can populate the products list. But I would like to populate it with only the products that are selected via a checkbox. I think I could do it by changing the action method to this: public ActionResult Delete(IList<Product> products, IList<int> toDelete) And passing the list of check boxes to the toDelete but I would really like to avoid changing the method signature if possible. Is there a way to pass only the selected items? Or am I going to have to write a custom ModelBinder?

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• In Google App Engine, what is the simplest way to keep a record of items that you have put into memc

  - by Chris Boesch

  I am starting to use memcache more frequently to avoid having to recalculate things between page requests. When the memcache periodically clears, as it is designed to do, I have to start all over rebuilding various items that I have placed in memcache. What I would like to do is create a very simple model that enables me to periodically save the items that I put into memcache based on the memcache keys that I'm using along with a datetime that is related to the data being memcached. What is the best way to do this? I'm looking for something like this: class MemcacheRecord(db.Model): key = db.StringProperty(required=True) value = #Something that can store whatever memcache can validThru = db.DateTimeProperty(required=True) def set(self, key, value, validThru): #Save a new memcache record newMemcacheRecord = MemcacheRecord(key=key, value=value, validThru=validThru) .. return True # or False def get_latest(self, key): #Get the memcache record with the most recent validThru datetime latestMemcacheRecord = MemcacheRecord.all().order('-validThru').get() return {'validThru':latestMemcacheRecord.validThru, 'value':latestMemcachRecord.value}

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• Can I use Win32 FreeType without the .dll file?

  - by Khatharr

  Hello. I'm teaching myself OpenGL and I'm implementing ttf text rendering using FreeType 2. I downloaded the library from http://gnuwin32.sourceforge.net/packages/freetype.htm and after a couple of minor issues I got it running properly. The thing that's bothering me is that I have to place a copy of freetype6.dll in the directory with my executable in order for the thing to run. I generally try to avoid a bunch of unnecessary dll files floating around. I'm sort of new to windows programming, but from what I understand most libraries can be built to run fully from a lib rather than requiring a dll at runtime. Looking through the documentation from FT is making my brain melt, so I thought I would ask here to see if there were any devs that have worked with FT before and if so, do they know how to build the library such that no dll is required at runtime. Thank you in advance for any advice or support.

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• Reducing Code Repetition: Calling functions with slightly different signatures

  - by Brian

  Suppose I have two functions which look like this: public static void myFunction1(int a, int b, int c, string d) { //dostuff someoneelsesfunction(c,d); //dostuff2 } public static void myFunction2(int a, int b, int c, Stream d) { //dostuff someoneelsesfunction(c,d); //dostuff2 } What would be a good way to avoid repeated dostuff? Ideas I've thought of, but don't like: I could make d an object and cast at runtype based on type, but this strikes me as not being ideal; it removes a type check which was previously happening at compile time. I could also write a private helper class that takes an object and write both signatures as public functions. I could replace dostuff and dostuff2 with delegates or function calls or something.

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• Coordinating the logging output from a web app installed in a SharePoint farm.

  - by Kelly French

  We are deploying web parts to SharePoint 2007 and would like to include logging (log4net). The ideal solution would be to use a database appender to avoid the problems with knowing which actual server is executing the web part. This questions has been helpful: http://stackoverflow.com/questions/219668/sharepoint-and-log4net. I've got log4net working in a stand-alone web app using Visual Studio dev server using the web.config for the log4net settings and a file appender for the output. I'd like to transition to SharePoint and still use the log file output so I can make sure it's all working first, then change the config around to log to a database. Is this going to be too much trouble? How have other developers added log4.net into their solutions for SharePoint?

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• NHibernate mapping one table on two classes with where selection

  - by Rene Schulte

  We would like to map a single table on two classes with NHibernate. The mapping has to be dynamically depending on the value of a column. Here's a simple example to make it a bit clearer: We have a table called Person with the columns id, Name and Sex. The data from this table should be mapped either on the class Male or on the class Female depending on the value of the column Sex. In Pseudocode: create instance of Male with data from table Person where Person.Sex = 'm'; create instance of Female with data from table Person where Person.Sex = 'f'; The benefit is we have strongly typed domain models and can later avoid switch statements. Is this possible with NHibernate or do we have to map the Person table into a flat Person class first? Then afterwards we would have to use a custom factory method that takes a flat Person instance and returns a Female or Male instance. Would be good if NHibernate (or another library) can handle this.

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• Model-Controller cyclic reference/design problem

  - by jasamer

  I have a CoreData entity X, and controllers for this entity, XController. Now there's another entity, XGroup, containing a collection of X entities, and a XGroupController. Now the problem is that XGroupController needs to interact with XController, and it would be nice to just pass XGroupController a XGroup to observe, and then get the XControllers from the X entities. So the question is: is it a good idea to store a (weak, to avoid retain cycles) reference to a controller in an entity? It just feels a bit "wrong". Is there another design pattern for this?

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• linux thread synchronization

  - by johnnycrash

  I am new to linux and linux threads. I have spent some time googling to try to understand the differences between all the functions available for thread synchronization. I still have some questions. I have found all of these different types of synchronizations, each with a number of functions for locking, unlocking, testing the lock, etc. gcc atomic operations futexes mutexes spinlocks seqlocks rculocks conditions semaphores My current (but probably flawed) understanding is this: semaphores are process wide, involve the filesystem (virtually I assume), and are probably the slowest. Futexes might be the base locking mechanism used by mutexes, spinlocks, seqlocks, and rculocks. Futexes might be faster than the locking mechanisms that are based on them. Spinlocks dont block and thus avoid context swtiches. However they avoid the context switch at the expense of consuming all the cycles on a CPU until the lock is released (spinning). They should only should be used on multi processor systems for obvious reasons. Never sleep in a spinlock. The seq lock just tells you when you finished your work if a writer changed the data the work was based on. You have to go back and repeat the work in this case. Atomic operations are the fastest synch call, and probably are used in all the above locking mechanisms. You do not want to use atomic operations on all the fields in your shared data. You want to use a lock (mutex, futex, spin, seq, rcu) or a single atomic opertation on a lock flag when you are accessing multiple data fields. My questions go like this: Am I right so far with my assumptions? Does anyone know the cpu cycle cost of the various options? I am adding parallelism to the app so we can get better wall time response at the expense of running fewer app instances per box. Performances is the utmost consideration. I don't want to consume cpu with context switching, spinning, or lots of extra cpu cycles to read and write shared memory. I am absolutely concerned with number of cpu cycles consumed. Which (if any) of the locks prevent interruption of a thread by the scheduler or interrupt...or am I just an idiot and all synchonization mechanisms do this. What kinds of interruption are prevented? Can I block all threads or threads just on the locking thread's CPU? This question stems from my fear of interrupting a thread holding a lock for a very commonly used function. I expect that the scheduler might schedule any number of other workers who will likely run into this function and then block because it was locked. A lot of context switching would be wasted until the thread with the lock gets rescheduled and finishes. I can re-write this function to minimize lock time, but still it is so commonly called I would like to use a lock that prevents interruption...across all processors. I am writing user code...so I get software interrupts, not hardware ones...right? I should stay away from any functions (spin/seq locks) that have the word "irq" in them. Which locks are for writing kernel or driver code and which are meant for user mode? Does anyone think using an atomic operation to have multiple threads move through a linked list is nuts? I am thinking to atomicly change the current item pointer to the next item in the list. If the attempt works, then the thread can safely use the data the current item pointed to before it was moved. Other threads would now be moved along the list. futexes? Any reason to use them instead of mutexes? Is there a better way than using a condition to sleep a thread when there is no work? When using gcc atomic ops, specifically the test_and_set, can I get a performance increase by doing a non atomic test first and then using test_and_set to confirm? *I know this will be case specific, so here is the case. There is a large collection of work items, say thousands. Each work item has a flag that is initialized to 0. When a thread has exclusive access to the work item, the flag will be one. There will be lots of worker threads. Any time a thread is looking for work, they can non atomicly test for 1. If they read a 1, we know for certain that the work is unavailable. If they read a zero, they need to perform the atomic test_and_set to confirm. So if the atomic test_and_set is 500 cpu cycles because it is disabling pipelining, causes cpu's to communicate and L2 caches to flush/fill .... and a simple test is 1 cycle .... then as long as I had a better ratio of 500 to 1 when it came to stumbling upon already completed work items....this would be a win.* I hope to use mutexes or spinlocks to sparilngly protect sections of code that I want only one thread on the SYSTEM (not jsut the CPU) to access at a time. I hope to sparingly use gcc atomic ops to select work and minimize use of mutexes and spinlocks. For instance: a flag in a work item can be checked to see if a thread has worked it (0=no, 1=yes or in progress). A simple test_and_set tells the thread if it has work or needs to move on. I hope to use conditions to wake up threads when there is work. Thanks!

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• Generate links for routes with non-parameter url segments on ASP.NET MVC 2

  - by spapaseit

  I have a route defined with several hardcoded (non-parameter) segments: routes.MapRoute(null, "suggestion/list/by/{tag}", new { controller = "Suggestion", action = "List", tag = UrlParameter.Optional }); Suppose I'm in the Index view of SuggestionController, which has a Suggestion object for Model, how can I create a link that matches that route? I'd rather use one of the provided helpers and keep the route name as null in order to avoid hard-coding to much on my views, but I can't figure out how to user these non-parameter segments in Html.ActionLink or RouteLink methods. I've even tried to render the link using plain ol' html <a href="/suggestion/list/by/<%=Model.Tag %>"><%=Model.Tag %></a> but this somehow didn't match the route either. There's probably a very simple solution and I might be over-complicating things in mi mind, but I'm at a loss. Any ideas? Thanks in advance.

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• It's possible to don't pass in GET some fields of a form?

  - by avastreg

  I have a form with some input texts passed in GET, and i don't want to have in GET all the fields; i want to avoid empty fields. So, a concrete example for: <form method="GET" action="an_url"> <input type="text" name="field1"/> <input type="text" name="field2"/> <input type="text" name="field3"/> <input type="submit" value="submit"/> </form> I supposed that fields disabled by html attribute "disabled" shouldn't be passed to GET. So i have done a js (based on jquery) to disable empty fields on submit, something like this: $("form").submit(function() { $(this).find("input[type=text]").each( function () { if (!$.trim($(this).val())) { $(this).attr("disabled", "true"); } }); }); However, this doesn't work. Any ideas?

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• Change an access Primary key with relationships

  - by DiegoMaK

  I have a database in access 2007 accdb extension , there are more or less 30-40 tables with related primary key "local_number". it is a text primary key with 10 lenght. How can I change the length of this primary key to 30 WITHOUT delete previosly all the 30 relationship. 2,A similar question. I need add a compose primary key to my PK "local_number". I need Add a "Date" as composed PK. Then access just allow this if I first delete all relationships. How can Avoid this warning and change my PK ignoring this message.

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• How to force asp.net MVC 2 to redirect to default controller/action

  - by Chris

  In a brand new ASP.NET MVC2 project, I want the user to be redirected to http://<mysite>/home/index rather than http://<mysite>/ We do this with our other sites for tracking purposes, to avoid the scenario where hits to the same default page show up as http://<mysite>/ http://<mysite>/default.aspx How do I accomplish this so that http://<mysite>/ automatically redirects to whatever default controller/action I have set up in my routing? Please note that I am aware the two are functionally equivalent, as the default controller action will be executed either way. I'm just interested in forcing consistent URLs in the browser.

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• How to configure MySQL connection properties with Spring, Hibernate 3.3 and c3p0?

  - by sfussenegger

  I am currently in the process of upgrading an application from Hibernate 3.2 to Hibernate 3.3. I though I'd stick with the default connection pool (Hibernate changed its default from Commons DBCP to c3p0) as I don't have any good reason to choose a non-default pool. At least non but having used DBCP before. The upgrade went pretty much without any problems so far. The only thing I can't get to work is passing properties to the underlying MySQL JDBC4Connection. Up to now, I used DBCP's BasicDataSource.addConnectionProperty(String,String) to pass properties (useUnicode=true, characterEncodin=UTF-8, characterSetResults=UTF-8, zeroDateTimeBehavior=convertToNull). However, I can't find any way to do the same with c3p0 other than including them in the JDBC URL. (That's something I'd like to avoid as I wanna keep the URL configurable without forcing users to include those parameters.) So far, I've tried to use a ConnectionCustomizer without success. Any other suggestions?

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• Launching Vim via Lua

  - by Keith Pimmel

  I'm writing a simple little Lua commandline app that will build a static website. I'm storing my fragments in a sqlite database. Retrieving the data from the db is straightforward as is saving it; my question comes from editing the data. Is there an elegant way to pipe the data from Lua to vim? Can vim edit a memory buffer and return it? I was planning on launching the editor via os.execute('vim') but only after grabbing a temporary file handle and dumping the database output into that. I would like to have to avoid touching the filesystem that way but that is my contingency plan.

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• How do I use Zend Cache on this particular problem

  - by davykiash

  I have an action that renders two different view scripts based on whether the user is logged in or not. class IndexController extends Zend_Controller_Action { .... public function indexAction() { $auth = Zend_Auth::getInstance(); if($auth->hasIdentity()) { $this->render('indexregistered'); return; } else { $this->render('indexpublic'); return; } } .... } I have seen quite some useful examples on how to use the Zend Cache and they seem to be based on the fact that the action renders one particular script. What am really looking at is the best approach to cache the the indexpublic script does get quite some hits and I would live to avoid the Zend MVC overhead if possible.

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• cscript - print output on same line on console?

  - by Guy

  If I have a cscript that outputs lines tothe screen, how do I avoid the "line feed" after each print? Example: for a = 1 to 10 print "." REM (do something) next The expected output should be: .......... Not: . . . . . . . . . . In the past I've used to print the "up arrow character" ASCII code. Can this be done in cscript?

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• Filtering Filenames with bash

  - by Stefan Liebenberg

  I have a directory full of log files in the form ${name}.log.${year}{month}${day} such that they look like this: logs/ production.log.20100314 production.log.20100321 production.log.20100328 production.log.20100403 production.log.20100410 ... production.log.20100314 production.log.old I'd like to use a bash script to filter out all the logs older than x amount of month's and dump it into *.log.old X=6 #months LIST=*.log.*; for file in LIST; do is_older = file_is_older_than_months( ${file}, ${X} ); if is_older; then cat ${c} >> production.log.old; rm ${c}; fi done; How can I get all the files older than x months? and... How can I avoid that *.log.old file is included in the LIST attribute? Thank you Stefan

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• Opposite of Bloom filter?

  - by abc

  Hi, I'm trying to optimize a piece of software which is basically running millions of tests. These tests are generated in such a way that there can be some repetitions. Of course, I don't want to spend time running tests which I already ran if I can avoid it efficiently. So, I'm thinking about using a Bloom filter to store the tests which have been already ran. However, the Bloom filter errs on the unsafe side for me. It gives false positives. That is, it may report that I've ran a test which I haven't. Although this could be acceptable in the scenario I'm working on, I was wondering if there's an equivalent to a Bloom filter, but erring on the opposite side, that is, only giving false negatives. I've skimmed through the literature without any luck.

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• Yield In VB.NET

  - by MagicKat

  C# has the keyword called yield. VB.NET lacks this keyword. I am curious how some of the VB programmers have gotten around the lack of this keyword. Do you implement your own iterator class? Or do you try and code to avoid the need of an iterator? The yield keyword does force the compiler to do some coding behind the scenes. http://blogs.msdn.com/oldnewthing/archive/2008/08/12/8849519.aspx is a good example of that.

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• Cleaning strings in R: add punctuation w/o overwriting last character

  - by spearmint

  I'm new to R and unable to find other threads with a similar issue. I'm cleaning data that requires punctuation at the end of each line. I am unable to add, say, a period without overwriting the final character of the line preceding the carriage return + line feed. Sample code: Data1 <- "%trn: dads sheep\r\n*MOT: hunn.\r\n%trn: yes.\r\n*MOT: ana mu\r\n%trn: where is it?" Data2 <- gsub("[^[:punct:]]\r\n\\*", ".\r\n\\*", Data1) The contents of Data2: [1] "%trn: dads shee.\r\n*MOT: hunn.\r\n%trn: yes.\r\n*MOT: ana mu\r\n%trn: where is it?" Notice the "p" of sheep was overwritten with the period. Any thoughts on how I could avoid this?

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• Adding pdb files to VSS

  - by George

  Every time I try to compile my web app, I am prompted if i want to add pdb extensioned files to VSS. I thought pdb files do not belong in VSS see a previous post. Is there any way to prevent them from being added. I cannot even logically delete them from VSS because a previous version has been logically deleted and if I were to delete the current version, the previous version would have to be purged, for which I need vss admin rights that I do not have. I just can't get a handle on how to avoid getting a million files added to VSS that prevent otehr develoeprs from compiling their solutions because they have unchecked out read only copies. Is the only solution to check them in but flip the readonly flag off locally? This is not a good option in my mind.

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• Help with complex sql query

  - by eugeneK

  To make story short, i'm building self-learning banner management system. Users will be able to insert these banners to their site when banners will be shown based on sales/impressions ratio. I have 4 tables Banners bannerID int bannerImage varchar.... SmartBanners smartBannerID int smartBannerArrayID int bannerID int impressionsCount int visibility tinyint (percents) SmartBannerArrays smartBannerArrayID int userID int Statistics bannerID int saleAmountPerDay decimal... Each night i need to generate new "visibility" for each SmartBanner based on whole SmartBannerArray that same user has. So i need to get sum of impressions and sales for each bannerID in SmartBannerArray. All comes to my mind is to use double cursor, one will loop thought SmartBannerArrays get needed values for sum of impressions and sales and then inner loop which will access each SmartBanner and change it's "visibility" percentage based on (sales/impressions)/(sumOfSales/sumOfImpressions)*100 Hope you get the picture... Is there any other way to design better tables or not to use double cursor to avoid server overload ?

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• How to edit localized forms all at one time in Visual Studio

  - by SoMoS

  Hello, I have several forms that are localized to multiple languages. If I do a change on one form (for example, changing the size of a textbox) the change is done only on the localized version of the Form that I have currently selected. Is there a way of extending the change I've done the different localized versions of the same Form to avoid having to go one by one doing the same change by hand? Thanks in advance for your help. EDIT: I'm talking about different forms when the real thign is that you have one form and several resources. The point is that at the end is just like if you have different forms for each locale because the form is built with the data from the resource. The problem is still the same because the edits done on the form are stored at one resource file and I have to put by hand those edits in all the resources.

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• Communication between Page and User Controls

  - by Narmatha Balasundaram

  I have a main page that has multiple user controls on it. All the user controls have static text and some data to be retrieved from the DB. The aysnchronous DB call is clubbed at the page level and one call is made to avoid multiple calls (in the different user controls) to get the same data. I want the page and user controls to load initially with the static text and later refresh the contents obtained from the server. To sum it all up, Page Loads = Asyn calls fired on page load = Data received back from the server (XML/text/whatever) = User controls to load with this data using AJAX. What methods do I have to let the user controls know that I have the data from the server and they need to update with this data?

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