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  • Stored procedures vs. parameter binding

    - by Gagan
    I am using SQL server and ODBC in visual c++ for writing to the database. Currently i am using parameter binding in SQL queries ( as i fill the database with only 5 - 6 queries and same is true for retrieving data). I dont know much about stored procedures and I am wondering how much if any performance increase stored procedures have over parameter binding as in parameter binding we prepare the query only once and just execute it later in the program for diferent set of values of variables.

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  • Refactoring Singleton Overuse

    - by drharris
    Today I had an epiphany, and it was that I was doing everything wrong. Some history: I inherited a C# application, which was really just a collection of static methods, a completely procedural mess of C# code. I refactored this the best I knew at the time, bringing in lots of post-college OOP knowledge. To make a long story short, many of the entities in code have turned out to be Singletons. Today I realized I needed 3 new classes, which would each follow the same Singleton pattern to match the rest of the software. If I keep tumbling down this slippery slope, eventually every class in my application will be Singleton, which will really be no logically different from the original group of static methods. I need help on rethinking this. I know about Dependency Injection, and that would generally be the strategy to use in breaking the Singleton curse. However, I have a few specific questions related to this refactoring, and all about best practices for doing so. How acceptable is the use of static variables to encapsulate configuration information? I have a brain block on using static, and I think it is due to an early OO class in college where the professor said static was bad. But, should I have to reconfigure the class every time I access it? When accessing hardware, is it ok to leave a static pointer to the addresses and variables needed, or should I continually perform Open() and Close() operations? Right now I have a single method acting as the controller. Specifically, I continually poll several external instruments (via hardware drivers) for data. Should this type of controller be the way to go, or should I spawn separate threads for each instrument at the program's startup? If the latter, how do I make this object oriented? Should I create classes called InstrumentAListener and InstrumentBListener? Or is there some standard way to approach this? Is there a better way to do global configuration? Right now I simply have Configuration.Instance.Foo sprinkled liberally throughout the code. Almost every class uses it, so perhaps keeping it as a Singleton makes sense. Any thoughts? A lot of my classes are things like SerialPortWriter or DataFileWriter, which must sit around waiting for this data to stream in. Since they are active the entire time, how should I arrange these in order to listen for the events generated when data comes in? Any other resources, books, or comments about how to get away from Singletons and other pattern overuse would be helpful.

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  • How do I use a string as a keyword argument?

    - by Issac Kelly
    Specifically, I'm trying to use a string to arbitrairly filter the ORM. I've tried exec and eval solutions, but I'm running into walls. The code below doesn't work, but it's the best way I know how to explain where I'm trying to go from gblocks.models import Image f = 'image__endswith="jpg"' # Would be scripted in another area, but passed as text <user input> d = Image.objects.filter(f) #for the non-django pythonistas: d = Image.objects.filter(image__endswith="jpg") # would be the non-dynamic equivalent.

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  • Updating Textures on Runtime in OpenSceneGraph

    - by Abhishek Bansal
    I am working on a project in which i am required to capture frames from external device video and render them on openSceneGraph Node. I am also using GLSL shaders. But i dont know how to update textures on runtime. For other uniforms we need to make callbacks but do we also need to make callbacks for samplers in glsl and openSceneGraph ? My code looks like this. All i am getting right now is a black window. osg::ref_ptr<osg::Geometry> pictureQuad = osg::createTexturedQuadGeometry(osg::Vec3(0.0f,0.0f,0.0f), osg::Vec3(_deviceNameToImageFrameMap[deviceName].frame->s(),0.0f,0.0f), osg::Vec3(0.0f,0.0f,_deviceNameToImageFrameMap[deviceName].frame->t()), 0.0f, 1.0f,_deviceNameToImageFrameMap[deviceName].frame->s(), _deviceNameToImageFrameMap[deviceName].frame->t()); //creating texture and setting up parameters for video frame osg::ref_ptr<osg::TextureRectangle> myTex= new osg::TextureRectangle(_deviceNameToImageFrameMap[deviceName].frame.get()); myTex->setFilter(osg::Texture::MIN_FILTER,osg::Texture::LINEAR); myTex->setFilter(osg::Texture::MAG_FILTER,osg::Texture::LINEAR); myTex->setWrap(osg::Texture::WRAP_S, osg::Texture::CLAMP_TO_EDGE); myTex->setWrap(osg::Texture::WRAP_T, osg::Texture::CLAMP_TO_EDGE); _videoSourceNameToNodeMap[sourceName].geode = new osg::Geode(); _videoSourceNameToNodeMap[sourceName].geode->setDataVariance(osg::Object::DYNAMIC); _videoSourceNameToNodeMap[sourceName].geode->addDrawable(pictureQuad.get()); //apply texture to node _videoSourceNameToNodeMap[sourceName].geode->getOrCreateStateSet()->setTextureAttributeAndModes(0, myTex.get(), osg::StateAttribute::ON); _videoSourceNameToNodeMap[sourceName].geode->getOrCreateStateSet()->setMode(GL_DEPTH_TEST, osg::StateAttribute::OFF); _videoSourceNameToNodeMap[sourceName].geode->setDataVariance(osg::Object::DYNAMIC); //Set uniform sampler osg::Uniform* srcFrame = new osg::Uniform( osg::Uniform::SAMPLER_2D, "srcFrame" ); srcFrame->set(0); //Set Uniform Alpha osg::Uniform* alpha = new osg::Uniform( osg::Uniform::FLOAT, "alpha" ); alpha->set(.5f); alpha->setUpdateCallback(new ExampleCallback()); //Enable blending _videoSourceNameToNodeMap[sourceName].geode->getOrCreateStateSet()->setMode( GL_BLEND, osg::StateAttribute::ON); //Adding blend function to node osg::BlendFunc *bf = new osg::BlendFunc(); bf->setFunction(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); _videoSourceNameToNodeMap[sourceName].geode->getOrCreateStateSet()->setAttributeAndModes(bf); //apply shader to quad _videoSourceNameToNodeMap[sourceName].geode->getOrCreateStateSet()->setAttributeAndModes(program, osg::StateAttribute::ON); //add Uniform to shader _videoSourceNameToNodeMap[sourceName].geode->getOrCreateStateSet()->addUniform( srcFrame ); _videoSourceNameToNodeMap[sourceName].geode->getOrCreateStateSet()->addUniform( alpha );

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  • Writing " to a file in bash.

    - by S1syphus
    Simply I need to write "echo" t${count} = "$"t${count}" To a text file, including all the So the output would be something like: echo " t1 = $t1" With " as they are. So I have tried: count=1 saveIFS="$IFS" IFS=$'\n' array=($(<TEST.txt)) IFS="$saveIFS" for i in "${array[@]}" do echo "echo" t${count} = "$"t${count}"" (( count++ )) done >> long1.txt And variations on this such as: echo "echo" """"" t${count} = "$"t${count}"" But I guess the wrapping in double " is only for variables. Ideas?

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  • In google app engine, how to iterate through form fields (python, wsgiref.handlers)

    - by MarcoB
    Using python and wsgiref.handlers, I can get a single variable from a form with self.handler.request.get(var_name), but how do I iterate through all form variables, be they from GET and POST? Is it something like this? for field in self.handler.request.fields: value = self.handler.request.get(field) Again, it should include both fields included in the POST and fields from the query string, as in a GET request. Thanks in advance folks...

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  • Is there any library to represent SQL queries as objects in Java code?

    - by Pregzt
    I was wondering if there is any library that can be used to represent SQL queries as objects in Java. In the code I have plenty of static variables of type java.lang.String that are hand written SQL queries. I would be looking for library having a nice fluent API that allows me to represent the queries as objects rather than strings. Example: Query q = select("DATE", "QUOTE") .from("STOCKMARKET") .where(eq("CORP", "?")) .orderBy("DATE", DESC);

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  • Creating Class Properties in Visual Studio

    - by pm_2
    Using the standard VS IDE, is there a fast way to create class properties that are linked to the local variables? The class diagram seems to provide something, but it basically just created a property stub. Is there something better / easier out there ?

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  • Does variable name length matter for performance C#?

    - by MadBoy
    I've been wondering if using long descriptive variable names in WinForms C# matters for performance? I'm asking this question since in AutoIt v3 (interpreted language) it was brought up that having variables with short names like aa instead of veryLongVariableName is much much faster (when program is bigger then 5 liner). I'm wondering if it's the same in C#?

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  • get data from a querystring

    - by regwe
    i have this querystring that shall open up my page. http://www.a1-one.com/[email protected]&stuid=123456 Now when this page loads, on page_load, I want to pick up email and stuid in two different variables. So I can use them to insert into my database (sql server) how can this be done in vb.net

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  • CakePHP - Paginate / Query: find lowest of multiple fields & order by it

    - by Atea
    I am using CakePHP for a price-comparison website. I have a table products with fields: id, pride_regular, price_action. I would like to combine the fields price_regular and price_action into a dynamic field: price. The lowest value of these two fields should be the value of the new price field. Also I want to order on it Ascending. Should I use a custom MySQL-query?

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  • Why does the Java compiler complain about a local variable not having been initialized here?

    - by pele
    int a = 1, b; if(a > 0) b = 1; if(a <= 0) b = 2; System.out.println(b); If I run this, I receive: Exception in thread "main" java.lang.Error: Unresolved compilation problem: The local variable b may not have been initialized at Broom.main(Broom.java:9) I know that the local variables are not initialized and is your duty to do this, but in this case, the first if doesn't initialize the variable?

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  • Django context processor gets AnonymousUser

    - by myfreeweb
    instead of User. def myview(request): return render_to_response('tmpl.html', {'user': User.objects.get(id=1}) works fine and passes User to template. But def myview(request): return render_to_response('tmpl.html', {}, context_instance=RequestContext(request)) with a context processor def user(request): from django.contrib.auth.models import User return {'user': User.objects.get(id=1)} passes AnonymousUser, so I can't get the variables I need :( What's wrong?

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  • How to find the only UILabel in a view and hide it?

    - by tarnfeld
    I am adding a UILabel as a subview to a UIView and sometime later I want to hide it. It is assigned to a variable but I don't think setting the variables property Hidden after it's been added to the view will work (well it doesn't seem to anyway). Is there a way to loop through the subviews in a view and then find the one that has a specific tag or is of type UILabel that I could then remove?

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