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• Does DB2 have an "insert or update" statement?

  - by Mikael Eriksson

  From my code (Java) I want to ensure that a row exists in the database (DB2) after my code is executed. My code now does a select and if no result is returned it does an insert. I really don't like this code since it exposes me to concurrency issuses when running in a multi-threaded environment. What I would like to do is to put this logic in DB2 instead of in my Java code. Does DB2 have an "insert-or-update" statement? Or anything like it that I can use? For example: insertupdate into mytable values ('myid') Another way of doing it would probably be to allways do the insert and catch "SQL-code -803 primary key already exists", but I would like to avoid that if possible.

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• BLL returning the right Type of an instance

  - by Younes

  I have a class "Artikel" and there i write some Business Logic. I also have a class "tArtikel" which is a type. In my class "Artikel" I work with "tArtikel" and returns are of that type. Now when i instantiate an "Artikel" i want it to be of type "tArtikel", so what i tried in my code is: public tArtikel Artikel() { tArtikel artikel = new tArtikel(); } Which results in: "'Artikel' member names cannot be the same as their enclosing type". How would i set this up correctly?

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• How do I use theme preprocessor functions for my own templates?

  - by Jergason

  I have several .tpl.php files for nodes, CCK fields, and Views theming. These template files have a lot of logic in them to move things around, strip links, create new links, etc. I understand that this is bad development and not "The Drupal Way". If I understand correctly, "The Drupal Way" is to use preprocessor functions in your template.php file to manipulate variables and add new variables. A few questions about that: Is there a naming convention for creating a preprocessor function for a specific theme? For example, if I have a CCK field template called content-field-field_transmission_make_model.tpl, how would I name the preprocessor function? Can I use template preprocessor functions for node templates, CCK field templates, and Views templates? Do they have different methods of modifying template variables or adding new ones?

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• Language Agnositc Basic Programming Question

  - by Rachel

  This is very basic question from programming point of view but as I am in learning phase, I thought I would better ask this question rather than having an misunderstanding or narrow knowledge about the topic. So do excuse me if somehow I mess it up. Question: Let say I have class A,B,C and D now class A has some piece of code which I need to have in class B,C and D so I am extending class A in class B, class C, and class D Now how can I access the function of class A in other classes, do I need to create an object of class A and than access the function of class A or as am extending A in other classes than I can internally call the function using this parameter. If possible I would really appreciate if someone can explain this concept with code sample explaining how the logic flows.

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• what pattern to use for multi-argument method?

  - by Omid S

  I have a method with the following signature: foo (Sample sample, Aliquot aliquot) "foo" needs to alter a Sample object, either the first argument or from the second argument it can extract its Sample. For example: foo (Sample sample, Aliquot aliquot) { Sample out = null; if (sample != null) out = sample else out = aliquot.getSample() return out; } But that is so un-elegant, other than reading the API a developer does not know the reference of the first argument overrides the Sample of the second argument. Now, I could change "foo" to foo (SomeMagicalObject bar) where SomeMagicalObject is a tuple for Sample and Aliquot and holds some logic ... etc. But I am wondering, are there some patterns for this question?

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• How to implement following with Zend navigation?

  - by simple

  I have a top navigation and a side one Home | Tours | Booking Tour1 ------ Tour2 ------ Tour3 I show the side menu depending on a active top item. But sometimes when the side menu item is clicked I have to show that items children instead of the sidemenu. When no children exist I just show Children of a top menu depending on the active item. I an really having difficulties implementing that kind a logic and any help would be appreciated. //Comment button is not working so I will add comments here After stumbling the zend navigation view helpers, I am coming to the point - Understanding the concept of how in zend V part of MVC is implemented can save someone who is new to the framework many hours. As said in the answer to this question - "Use what is available", thought first we have to know where to find what is already available out there - that is where comes handy to take a look at the concept of helpers and so forth.

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• How do views reduce code duplication?

  - by Debuger

  Hi! I read something like this about db views: Views are incredibly powerful and useful for one reason that stands out above all the other very good reasons. They reduce code duplication. That is, in most cases, the bottom line. If a query will be used in three or more places, then a view will drastically simplify your changes if the schema or query parameters change. I once had to edit 22 stored procedures to change some query logic. If the original architecture had utilized views, then I would have had only three changes. Can anyone explain to me how it works, and maybe give me some examples? Best regards!

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• Socket : can an asynchronous Receive returns without reading all the bytes I asked for?

  - by NorthWind

  Hi; I was reading an article on Vadym Stetsiak's blog about how to transfer variable length messages with async sockets (url: http://vadmyst.blogspot.com/2008/03/part-2-how-to-transfer-fixed-sized-data.html). He says : What to expect when multiple messages arrive at the server? While dealing with multiple messages one has to remember that receive operation can return arbitrary number of bytes being read from the net. Typically that size is from 0 to specified buffer length in the Receive or BeginReceive methods. So, even if I tell BeginReceive to read 100 bytes, it may read less than that and returns??? I am developing a network-enabled software (TCP/IP), and I always receive the same exact number of bytes I asked for. I don't even understand the logic : why would Receive completes asynchronously if it didn't get every byte I asked for ... just keep waiting. Maybe it has something to do with IP vs TCP? Thank you for your help.

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• JavaScript Metaprogramming: Reduce boilerplate of adding functions to a function queue

  - by thurn

  I'm working with animation in JavaScript, and I have a bunch of functions you can call to add things to the animation queue. Basically, all of these functions look like this: function foo(arg1, arg2) { _eventQueue.push(function() { // actual logic } } I'm wondering now if it would be possible to cut down on this boilerplate a little bit, though, so I don't need that extra "_eventQueue" line in the function body dozens of times. Would it be possible, for example, to make a helper function which takes an arbitrary function as an argument and returns a new function which is augmented to be automatically added to the event queue? The only problem is that I need to find a way to maintain access to the function's original arguments in this process, which is... complicated.

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• Specification, modeling and programming are principially the same, right?

  - by Gabriel Šcerbák

  In formal specifications based on abstract algebraic types and equational theory you use formulas of equational theory to specify theory. System which will satisfy those constraints is called in formal logic a model. Modeling is process of creating a model, which abstracts of some aspects, which are unnecessary details for a specific case. So concrete system has to adhere to created model in observed aspects. Programming is a process of creating a program which will have specific behaviour - will perform specific algorithms - and programming languages through different paradigms enable us to think in a certain specific way, which abstracts of some details, usually machine specific ones. So could we be doing all those things at the same time, because they are principially the same? Is declarative programming the nearest attempt to do that? Could we use some sort f programming languages which will be good for programming as well as for modeling and specification?

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• Rails flash hash violation of MVC?

  - by user94154

  I know Rails' flash hash is nothing new, but I keep running into the same problem with it. Controllers should be for business logic and db queries, not formatting strings for display to the user. But the flash hash is always set in the controller. This means that I need to hack and work around Rails to use Helpers that I made to format strings for the flash hash. Is this just a pragmatic compromise to MVC or am I missing something here? How do you deal with this problem? Or do you not even see it as one?

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• Accessing constructor from abstract base class with reflection

  - by craesh

  Hi! I'm playing around with Java's Reflection. I have an abstract class Base with a constructor. abstract class Base { public Base( String foo ) { // do some magic } } I have some further classes extending Base. They don't contain much logic. I want to instantiate them with Base's constructor, without having to write some proxy contructors in those derived classes. And of course, I want to instantiate those derived classes with Reflection. Say: Class cls = SomeDerivedClass.class; Constructor constr; constr = cls.getConstructor( new Class[] { String.class } ); // will return null Class clsBase = Base.class; constr = clsBase.getConstructor( new Class[] { String.class } ); // ok Base obj = (Base) constr.newInstance( new Object[] { "foo" } ); // will throw InstantiationException because it belongs to an abstract class Any ideas, how I can instantiate a derived class with Base's constructor? Or must I declare those dumb proxy constructors?

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• How can I modify a custom object in an ASP.NET FormView based on a button click?

  - by David

  I have a FormView that modifies an instance of a custom class. The various form controls (TextBox, DropDownList etc.) are working fine. However, I want to include a Button that will modify the state of the DataItem based on some very simple logic. There is no form control which could control this change in a non-confusing way. So I tried adding a Button and modifying the state of the DataItem in the code-behind. But the problem I encounter is that the FormView's DataItem is null/nothing. From reading this SO question it seems the problem is that the item is not databound when the Button's Click event is fired. So, the question; Is it possible to get the DataItem for the FormView during a Button's Click event? and if not: what are my options for implementing this? Thanks in advance. Edit: I can include any code that might help

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• Injecting an XML fragment into the current document from an external file

  - by makenai

  I'm currently parsing an XML file using REXML and trying to come up with a way of inserting an XML fragment from an internal file. Currently, I'm using some logic like the following: doc.elements.each('//include') do |element| handleInclude( element ) end def handleInclude( element ) if filename = element.attributes['file'] data = File.open( filename ).read doc = REXML::Document.new( data ) element.parent.replace_child( element, doc ) end end Where my XML looks like the following: <include file="test.xml" /> But this seems a little bit clunky, and I'm worried that REXML might not always parse XML fragments correctly due to absence of a proper root node in some cases. Is there a better way of doing this? Concern #2: REXML seems not to pick up my changes after I replace elements. For example, after making a change: doc.elements.each('rootNode/*') do |element| end ..picks up neither the original element I replaced, nor the one I replaced it with. Is there some trick to getting REXML to rescan its' tree?

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• Using recode in R

  - by celenius

  I'm trying to use 'recode' in R (from the 'cars' package) and it is not working. I read in data from a .csv file into a data frame called 'results'. Then, I replace the values in the column 'Built_year', according to the following logic. recode(results$Built_year, "2 ='1950s';3='1960s';4='1970s';5='1980s';6='1990s';7='2000 or later'") When I check results$Built_year after doing this step, it appears to have worked. However, it does not store this value, and returns to its previous value. I don't understand why. Thanks. (at the moment something is going wrong and I can't see any of the icons for formatting)

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• Invoke private method with interface as argument

  - by Stephanie

  Hi, I've been attempting to invoke a private method whose argument is a parameter and I can't quite seem to get it right. Here's kind of how the code looks so far: public class TestClass { public TestClass(){ } private void simpleMethod( Map<String, Integer> testMap) { //code logic } } Then I attempt to use this to invoke the private method: //Hashmap Map <String, Integer> testMap = new HashMap <String, Integer>(); //method I want to invoke Method simpleMethod = TestClass.class.getDeclaredMethod("simpleMethod", Map.class); simpleMethod.setAccessible(true); simpleMethod.invoke(testClassObject, testMap); //Throws an IllegalArgumentException As you can see, it throws an IllegalArgumentException. I've attempted to cast the hashmap back to a map, but that didn't work. What am I doing wrong?

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• Get the number of calendar weeks between 2 dates in C#

  - by Phil Scholtes

  For the purposes of this question, let's assume the user will be from the US and will use the standard Gregorian calendar. So, a calendar week starts on Sunday and ends on Saturday. What I'm trying to do is determine the number of calendar weeks that exist between two dates. A perfect example of my problem exists in October 2010. Between 10/16 and 10/31 there are 4 calendar weeks. View a picture of October 2010 October 10 - October 16 October 17 - October 23 October 24 - October 30 October 31 - November 6 I'd prefer to stay away from any hardcoded logic like: if (Day == DayOfWeek.Saturday && LastDayOfMonth == 31) { ... } Can anyone think of a logical way to do this?

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• Kohana PHP - Multiple apps with shared model

  - by Josamoto

  I'm using Kohana 3 to create a website that has two applications, an admin application and the actual site frontend. I have separated my folders to have the two applications separated, so the hierarchy looks as follows: /applications /admin /classes /controller /... /site /classes /controller /.... My question is, how I need to go about creating a shared /model folder. Essentially, both the admin and site itself operates on the same data, so the database layer and business logic remains more or less the same. So to me, it makes sense to have a single model folder, sitting outside of the two application folders. Is it possible to achieve the following hierarchy: /applications /model --> Where model sits in a neatly generic location, accessible to all applications /admin /classes /controller /... /site /classes /controller /.... Thanks in advance!

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• .NET Database Apps: Your Preferred Setup

  - by mdvaldosta

  I'm struggling to settle into a pattern for developing typical database driven apps in C# and Visual Studio. There are so many ways to set them up, using drag/drop datasets and adapters or writing the queries manually in ADO.NET or Linq to SQL, Linq to Entities, to bind or not to data bind etc etc. Where to store the connection string, in app.config or in a method or both etc etc. So many tutorials and all of them are different. Everytime I write something I start hating the way it looks and works, so I scrap it and start over. It's getting a bit tedious. Maybe it's alittle of the OCD in me. Would any of you professional developers out there share your method of setting up and structuring your database logic and maybe some sample code? It's really how to go about organizing the code and the method(s) of interacting with SQL that I'm trying to get into a routine with, one that works and won't get me laughed at by someone reviewing it.

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• How to add Transactions with a DataSet created using the Add Connection Wizard?

  - by RoguePlanetoid

  I have a DataSet that I have added to my project where I can Insert and Add records using the Add Query function in Visual Studio 2010, however I want to add transactions to this, I have found a few examples but cannot seem to find one that works with these. I know I need to use the SQLClient.SQLTransaction Class somehow. I used the Add New Data Source Wizard and added the Tables/View/Functions I need, I just need an example using this process such as How to get the DataConnection my DataSet has used. Assuming all options have been set in the wizard and I am only using the pre-defined adapters and options asked for in this wizard, how to I add the Transaction logic to my Database. For example I have a DataSet called ProductDataSet with the XSD created for this, I have then added my Stock table as a Datasource and Added an AddStock method with a wizard, this also if a new item calls an AddItem method, if either of these fails I want to rollback the AddItem and AddStock in this case.

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• Rabbitmq queue sharding

  - by kolchanov

  I have to implement this scenario: An external application publish message to rabbitmq. This message has a client_id property. We can place this id to routing key or message header or some other property. I have to implement sharding in a exchange routng logic - the message should be delivered to specific queue based on the client_id range. Is it possible to implement in a standard exchanges? If not what exchange should I take as the base? How to dynamicly change client_id ranges?

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• Grand Central Strategy for Opening Multiple Files

  - by user276632

  I have a working implementation using Grand Central dispatch queues that (1) opens a file and computes an OpenSSL DSA hash on "queue1", (2) writing out the hash to a new "side car" file for later verification on "queue2". I would like to open multiple files at the same time, but based on some logic that doesn't "choke" the OS by having 100s of files open and exceeding the hard drive's sustainable output. Photo browsing applications such as iPhoto or Aperture seem to open multiple files and display them, so I'm assuming this can be done. I'm assuming the biggest limitation will be disk I/O, as the application can (in theory) read and write multiple files simultaneously. Any suggestions? TIA

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• SSIS Script Component Testing Strategy

  - by Paul Kohler

  This question is in respect to the script component specifically. I am aware of ssisUnit etc… With simple SSIS Scripts Components, it’s sufficient to let basic testing flesh out issues, however I am working with a script that has grown in complexity over time. To better test the functionality I am considering abstracting the script logic into a DLL that gets deployed with the package, and then use the custom component in the script. The advantage is that the function will be more testable etc but it’s one more deployment artefact that needs to be managed. My question is, does anyone know of a better way to test such an SSIS script in a more isolated manner than to run the whole package and examine the output?

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• Nothing = String.Empty (Why are these equal?)

  - by Ek0nomik

  I find it very puzzling that null equals String.Empty in VB.NET. There must be an explanation for it that I'm not understanding. Somehow, when the equality of String.Empty (which has an object type of string) is tested against Nothing (which has no type) the test returns true. It just seems like a turn around in logic to me. In SQL if I were to compare an empty char or varchar against a null value, the test wouldn't return true. A null value is not the same as an empty string in this case. Yet in VB.NET they are equal. I'd love it if someone could provide a good explanation around this.

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• "Verbose Dictionary" in C#, 'override new' this[] or implement IDictionary

  - by Benjol

  All I want is a dictionary which tells me which key it couldn't find, rather than just saying The given key was not present in the dictionary. I briefly considered doing a subclass with override new this[TKey key], but felt it was a bit hacky, so I've gone with implementing the IDictionary interface, and passing everything through directly to an inner Dictionary, with the only additional logic being in the indexer: public TValue this[TKey key] { get { ThrowIfKeyNotFound(key); return _dic[key]; } set { ThrowIfKeyNotFound(key); _dic[key] = value; } } private void ThrowIfKeyNotFound(TKey key) { if(!_dic.ContainsKey(key)) throw new ArgumentOutOfRangeException("Can't find key [" + key + "] in dictionary"); } Is this the right/only way to go? Would newing over the this[] really be that bad?

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