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  • .NET Developer Basics – Recursive Algorithms

    Recursion can be a powerful programming technique when used wisely. Some data structures such as tree structures lend themselves far more easily to manipulation by recursive techniques. As it is also a classic Computer Science problem, it is often used in technical interviews to probe a candidate's grounding in basic programming techniques. Whatever the reason, it is well worth brushing up one's understanding with Damon's introduction to Recursion.

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  • SQL Insert Into Statement

    - by Derek Dieter
    The “insert into” statement is used in order to insert data into an existing table. The syntax for this is fairly simple. In the first section of the statement, you specify the table name and column names in which you are inserting data into. The second part is where the source of [...]

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  • Declaring variables in SQL

    - by Tim Hibbard
    I would like to blog more about the problems I encounter on a daily basis.  I find that taking 10 minutes or so to write a simple solution to my problems helps me retain that information. I always forget the specific syntax to declaring variables in T-SQL.  declare @startdate datetime; declare @enddate datetime;   set @startdate = '04/01/2010'; set @enddate = '04/30/2010';   select count(id) from triphistory where tripdate between @startdate and @enddate

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  • Why would you use data structures (ie Binary Trees, Linked Lists) in your jobs/side projects? [closed]

    - by Chris2021
    It seems to me that, for everyday use, more primitive data structures like arrays get the job done just as well as a binary tree would. My question is how common is to use these structures when writing code for projects at work or projects that you pursue in your free time? I understand the better insertion time/deletion time/sorting time for certain structures but would that really matter that much if you were working with a relatively small amount of data?

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  • PL/SQL Records for Oracle Database Administrators

    It can be hard, as an Oracle Database administrator, to expand your PL/SQL skills due to a lack of good examples, not to mention that lines upon lines of syntax definitions can be somewhat of a turn-off. Steve Callan moves beyond the mundane to look at using a composite data type.

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  • How can I use cron-apt to download and install updates between midnight and 5am?

    - by rudivonstaden
    I have capped data which is essentially free between midnight and 5am. As a result, I would like to set Ubuntu to automatically download updates over that time. It seems that cron-apt is what I need, but the documentation and syntax is sketchy and unintuitive. Can anyone tell me how to use it to schedule downloads? It can install the updates at the same time as far as I'm concerned, but that's not such a big issue - I can run those at a later stage.

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  • XPath execution utility

    - by TATWORTH
    I have written an XPath test utility at http://commonxpath.codeplex.com/releases/view/96687This is a WPF application that allows you to enter some test XML and and an XPath expression. When writing such expressions it is important to get the XPath expression correct before embedding it into a program.The program is available as source under LGPL so you can run it both on your office and home PCs. There is a link to help on XPATH syntax.

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  • Recommended learning path?

    - by stairmast0r
    First, my current standing: I know C++ at an.. advanced beginner level? I've gone through a book, I know the syntax well enough, I know a fair amount of standard library functions, and I've programmed some simple console stuff with it. I'd probably be able to program more with it if I knew how to structure a program, but I just can't seem to wrap my head around the whole concept of structuring something remotely complex. I've messed around with Java for a day or two, and the syntax was extremely easy to get the hang of, except that I didn't really know any functions. I'm plenty willing to learn, and to work hard to do so, but I don't really know where to go from here. Now, at the risk of sounding cliche, what I'd like to become is someone like the great three of id; Carmack, Romero, and Abrash. To be considered a genius. I believe anything can be learned, and nothing mentally limits anyone except lack of desire to learn. But I don't know how to learn this. They learned by doing, and making do with what resources they had. On the other hand, I have access to almost any books I want, access to the internet, and access to a more than capable computer and software. Should I learn more languages? Assembly? LISP? BASIC? Haskell? Should I dive straight into advanced topics like OpenGL? Or should I wait until I feel I've come closer to mastering the simpler things, like console programs, first? Should I follow tutorials? Should I follow books? Should I just dive into writing something and follow a reference manual as I go? What order should I do all this in? How should I do it? I want to completely master this; to be considered a genius. The most perfect career I can imagine is to start the next id. I have the drive to do it, I just don't know where to begin...

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  • The Top Ways to Get Search Engine Optimization

    There are a lot of different ways to make money online, but there are some major similarities in the way to go about them. Whether you're starting an online affiliate business or you're opening up an e-commerce store, you're going to need traffic. Getting traffic to your website can be relatively complicated if you're barking up the wrong tree or you're paying for search traffic.

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  • Excellent C Tutorials

    - by nebffa
    I've looked high and low for C tutorials that have lots of exercises to do along the way, but in my experience all the guides I've found have mostly explanation with a bit of code pre-written, lacking exercises for you to do. I started learning Python using Learn Python the Hard Way, and for almost all other standard languages there are good sites to learn and grapple with the syntax - for example codecademy.com, programr.com. Is there any site like any of the above for C?

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  • Canonicalization (On Page Optimization of Duplicate Contents)

    In this article we have discussed about the process of canonicalization that was officially announced by search engines last year to optimize website to avoid indexing of duplicate contents. Further we have discussed a scenario with a real life example in which canonicalization can be helpful and then we have seen its syntax and usage.

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  • Mimicking Network Databases in SQL

    Unlike the hierarchical database model, which created a tree structure in which to store data, the network model formed a generalized 'graph' structure that describes the relationships between the nodes. Nowadays, the relational model is used to solve the problems for which the network model was created, but the old 'network' solutions are still being implemented by programmers, even when they are less effective.

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  • Is FFmpeg missing from the official repositories in 14.04?

    - by user254877
    I tried to install ffmpeg in trusty/Ubuntu 14.04 and got the following message: $sudo apt-get install ffmpeg Reading package lists... Done Building dependency tree Reading state information... Done Package ffmpeg is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source E: Package 'ffmpeg' has no installation candidate Why isn't the package available?

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  • Understanding the Role of Search Engines

    Have you ever thought of trying to rank your website in the search engines as climbing a mountain, constantly trying to reach the top? I know I have, but this would be an inaccurate depiction. Instead, think of the search engines more as an ever-growing tree, branching off into other markets but always needing a well establish root system to hold it in place. This root system is RELEVANCE.

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  • Problem in searching String array [on hold]

    - by user2573607
    I'm working on a bank interface project, where I have to search an array of string when the user types in his username. The array has 10 strings, but only the first string is recognized as a valid username...I'm positive that the syntax of the search technique(Linear Search) is correct, but I cannot seem to find the problem. The code however compiles properly. Any answer will be appreciated, TIA! Aparna

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  • Stairway to SQL Dialects Level 3: MySQL

    As part of the LAMP stack, MySQL is incredibly important for providing a reliable and platform-agnostic database platform for web development. This level looks at the syntax of MySQL and how to best port SQL code to a MySQL environment. NEW! The easiest way to deploy .NET codeDeploy ASP.NET applications fast, frequently, and without fuss, using Deployment Manager, the new tool from Red Gate. Try it now.

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  • Google, typography, and cognitive fluency for persuasion

    - by Roger Hart
    Cognitive fluency is - roughly - how easy it is to think about something. Mere Exposure (or familiarity) effects are basically about reacting more favourably to things you see a lot. Which is part of why marketers in generic spaces like insipid mass-market lager will spend quite so much money on getting their logo daubed about the place; or that guy at the bus stop starts to look like a dating prospect after a month or two. Recent thinking suggests that exposure effects likely spin off cognitive fluency. We react favourably to things that are easier to think about. I had to give tech support to an older relative recently, and suggested they Google the problem. They were confused. They could not, apparently, Google the problem, because part of it was that their Google toolbar had mysteriously vanished. Once I'd finished trying not to laugh, I started thinking about typography. This is going somewhere, I promise. Google is a ubiquitous brand. Heck, it's a verb, and their recent, jaw-droppingly well constructed Paris advert is more or less about that ubiquity. It trades on Google's integration into any information-seeking behaviour. But, as my tech support encounter suggests, people settle into comfortable patterns of thinking about things. They build schemas, and altering them can take work. Maybe the ubiquity even works to cement that. Alongside their online effort, Google is running billboard campaigns to advertise Chrome, a free product in a crowded space. They are running these ads in some kind of kooky Calibri / Comic Sans hybrid. Now, at first it seems odd that one of the world's more ubiquitous brands needs to run a big print campaign in public places - surely they have all the fluency they need? Well, not so much. Chrome, after all, is not the same as their core product, so there's some basic awareness work to do, and maybe a whole new batch of exposure effect to try and grab. But why the typeface? It's heavily foregrounded, and the ads are extremely textual. Plus, don't we all know that jovial, off-beat fonts look unprofessional, or something? There's a whole bunch of people who want (often rightly) to ban Comic Sans I wonder, though. Are Google trying to subtly disrupt cognitive fluency? There's an interesting paper (pdf) about - among other things - the effects of typography on they way people answer survey questions. Participants given the slightly harder to read question gave more abstract answers. The paper references other work suggesting that generally speaking, less-fluent question framing elicits more considered answers. The Chrome ad typeface is less fluent for print. Reactions may therefore be more considered, abstract, and disruptive. Is that, in fact, what Google need? They have brand ubiquity, but they want here to change accustomed behaviour, to get people to think about changing their browser. Is this actually a very elegant piece of persuasive information design? If you think about their "what is a browser?" vox pop research video, there's certainly a perceptual barrier they're going to have to tackle somehow.

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  • Does my use of the strategy pattern violate the fundamental MVC pattern in iOS?

    - by Goodsquirrel
    I'm about to use the 'strategy' pattern in my iOS app, but feel like my approach violates the somehow fundamental MVC pattern. My app is displaying visual "stories", and a Story consists (i.e. has @properties) of one Photo and one or more VisualEvent objects to represent e.g. animated circles or moving arrows on the photo. Each VisualEvent object therefore has a eventType @property, that might be e.g. kEventTypeCircle or kEventTypeArrow. All events have things in common, like a startTime @property, but differ in the way they are being drawn on the StoryPlayerView. Currently I'm trying to follow the MVC pattern and have a StoryPlayer object (my controller) that knows about both the model objects (like Story and all kinds of visual events) and the view object StoryPlayerView. To chose the right drawing code for each of the different visual event types, my StoryPlayer is using a switch statement. @implementation StoryPlayer // (...) - (void)showVisualEvent:(VisualEvent *)event onStoryPlayerView:storyPlayerView { switch (event.eventType) { case kEventTypeCircle: [self showCircleEvent:event onStoryPlayerView:storyPlayerView]; break; case kEventTypeArrow: [self showArrowDrawingEvent:event onStoryPlayerView:storyPlayerView]; break; // (...) } But switch statements for type checking are bad design, aren't they? According to Uncle Bob they lead to tight coupling and can and should almost always be replaced by polymorphism. Having read about the "Strategy"-Pattern in Head First Design Patterns, I felt this was a great way to get rid of my switch statement. So I changed the design like this: All specialized visual event types are now subclasses of an abstract VisualEvent class that has a showOnStoryPlayerView: method. @interface VisualEvent : NSObject - (void)showOnStoryPlayerView:(StoryPlayerView *)storyPlayerView; // abstract Each and every concrete subclass implements a concrete specialized version of this drawing behavior method. @implementation CircleVisualEvent - (void)showOnStoryPlayerView:(StoryPlayerView *)storyPlayerView { [storyPlayerView drawCircleAtPoint:self.position color:self.color lineWidth:self.lineWidth radius:self.radius]; } The StoryPlayer now simply calls the same method on all types of events. @implementation StoryPlayer - (void)showVisualEvent:(VisualEvent *)event onStoryPlayerView:storyPlayerView { [event showOnStoryPlayerView:storyPlayerView]; } The result seems to be great: I got rid of the switch statement, and if I ever have to add new types of VisualEvents in the future, I simply create new subclasses of VisualEvent. And I won't have to change anything in StoryPlayer. But of cause this approach violates the MVC pattern since now my model has to know about and depend on my view! Now my controller talks to my model and my model talks to the view calling methods on StoryPlayerView like drawCircleAtPoint:color:lineWidth:radius:. But this kind of calls should be controller code not model code, right?? Seems to me like I made things worse. I'm confused! Am I completely missing the point of the strategy pattern? Is there a better way to get rid of the switch statement without breaking model-view separation?

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  • dynamic? I'll never use that ... or then again, maybe it could ...

    - by adweigert
    So, I don't know about you, but I was highly skeptical of the dynamic keywork when it was announced. I thought to myself, oh great, just another move towards VB compliance. Well after seeing it being used in things like DynamicXml (which I use for this example) I then was working with a MVC controller and wanted to move some things like operation timeout of an action to a configuration file. Thinking big picture, it'd be really nice to have configuration for all my controllers like that. Ugh, I don't want to have to create all those ConfigurationElement objects... So, I started thinking self, use what you know and do something cool ... Well after a bit of zoning out, self came up with use a dynamic object duh! I was thinking of a config like this ...<controllers> <add type="MyApp.Web.Areas.ComputerManagement.Controllers.MyController, MyApp.Web"> <detail timeout="00:00:30" /> </add> </controllers> So, I ended up with a couple configuration classes like this ...blic abstract class DynamicConfigurationElement : ConfigurationElement { protected DynamicConfigurationElement() { this.DynamicObject = new DynamicConfiguration(); } public DynamicConfiguration DynamicObject { get; private set; } protected override bool OnDeserializeUnrecognizedAttribute(string name, string value) { this.DynamicObject.Add(name, value); return true; } protected override bool OnDeserializeUnrecognizedElement(string elementName, XmlReader reader) { this.DynamicObject.Add(elementName, new DynamicXml((XElement)XElement.ReadFrom(reader))); return true; } } public class ControllerConfigurationElement : DynamicConfigurationElement { [ConfigurationProperty("type", Options = ConfigurationPropertyOptions.IsRequired | ConfigurationPropertyOptions.IsKey)] public string TypeName { get { return (string)this["type"]; } } public Type Type { get { return Type.GetType(this.TypeName, true); } } } public class ControllerConfigurationElementCollection : ConfigurationElementCollection { protected override ConfigurationElement CreateNewElement() { return new ControllerConfigurationElement(); } protected override object GetElementKey(ConfigurationElement element) { return ((ControllerConfigurationElement)element).Type; } } And then had to create the meat of the DynamicConfiguration class which looks like this ...public class DynamicConfiguration : DynamicObject { private Dictionary<string, object> properties = new Dictionary<string, object>(StringComparer.CurrentCultureIgnoreCase); internal void Add<T>(string name, T value) { this.properties.Add(name, value); } public override bool TryGetMember(GetMemberBinder binder, out object result) { var propertyName = binder.Name; result = null; if (this.properties.ContainsKey(propertyName)) { result = this.properties[propertyName]; } return true; } } So all being said, I made a base controller class like a good little MVC-itizen ...public abstract class BaseController : Controller { protected BaseController() : base() { var configuration = ManagementConfigurationSection.GetInstance(); var controllerConfiguration = configuration.Controllers.ForType(this.GetType()); if (controllerConfiguration != null) { this.Configuration = controllerConfiguration.DynamicObject; } } public dynamic Configuration { get; private set; } } And used it like this ...public class MyController : BaseController { static readonly string DefaultDetailTimeout = TimeSpan.MaxValue.ToString(); public MyController() { this.DetailTimeout = TimeSpan.Parse(this.Configuration.Detail.Timeout ?? DefaultDetailTimeout); } public TimeSpan DetailTimeout { get; private set; } } And there I have an actual use for the dynamic keyword ... never thoguht I'd see the day when I first heard of it as I don't do much COM work ... oh dont' forget this little helper extension methods to find the controller configuration by the controller type.public static ControllerConfigurationElement ForType<T>(this ControllerConfigurationElementCollection collection) { Contract.Requires(collection != null); return ForType(collection, typeof(T)); } public static ControllerConfigurationElement ForType(this ControllerConfigurationElementCollection collection, Type type) { Contract.Requires(collection != null); Contract.Requires(type != null); return collection.Cast<ControllerConfigurationElement>().Where(element => element.Type == type).SingleOrDefault(); } Sure, it isn't perfect and I'm sure I can tweak it over time, but I thought it was a pretty cool way to take advantage of the dynamic keyword functionality. Just remember, it only validates you did it right at runtime, which isn't that bad ... is it? And yes, I did make it case-insensitive so my code didn't have to look like my XML objects, tweak it to your liking if you dare to use this creation.

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  • SQL Authority News – FalafelCON 2014: 2 days with the Best Developers in the World

    - by Pinal Dave
    I love presenting at various forums on various technologies. I am extremely excited that I got invited to speak at Falafel Conference 2014 in San Francisco. I will present two technology sessions on SQL Server. If you are into web development or if you just want to attend a conference with the best of the industry speakers, this may be the right conference for you. What set apart this conference from other conference is technology presented as well as speakers. Usually one has to attend very expensive and high scale event when they have to hear good speakers. At this conference, you will find quite a many industry legends are available to present on the bleeding edge technology. Here are few of the reasons why I believe you should attend this conference: Choose from four tracks covering Web, Mobile development and testing, Sitefinity, and Automated Testing, or attend sessions from all four! Learn from the best developers and testers in the business in an intimate setting. Surround yourself with your peers and the opportunity to network Learn about the latest platforms and technologies including Kendo UI, AngularJS, ASP.NET MVC, WebAPI, and more! Here are the details for the sessions which I am going to present at Falafel Conference. Secrets of SQL Server: Database Worst Practices Abstract: Chances are you have heard, or even uttered, this expression. This demo-oriented session will show many examples where database professionals were dumbfounded by their own mistakes, and could even bring back memories of your own early DBA days. The goal of this session is to expose the small details that can be dangerous to the production environment and SQL Server as a whole, as well as talk about worst practices and how to avoid them. Shedding light on some of these perils and the tricks to avoid them may even save your current job. After attending this session, Developers will only need 60 seconds to improve performance of their database server in their SharePoint implementation. We will have a quiz during the session to keep the conversation alive. Developers will walk out with scripts and knowledge that can be applied to their servers, immediately post the session. Additionally, all attendees of the session will have access to learning material presented in the session. The Unsung Hero Abstract: Slow Running Queries are the most common problem that developers face while working with SQL Server. While it is easy to blame the SQL Server for unsatisfactory performance, however the issue often persists with the way queries have been written, and how Indexes has been set up. The session will focus on the ways of identifying problems that slow down SQL Server, and Indexing tricks to fix them. Developers will walk out with scripts and knowledge that can be applied to their servers, immediately post the session. Register Now! I have learned from the Falafel Team that they are running out of tickets and soon they will close the registration.  For next 10 days the price for the registration is only USD 149. Trust me, you can’t get such a world class training and networking opportunity at such a low price. Click to Register Here! Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority News, T SQL

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  • How should I plan the inheritance structure for my game?

    - by Eric Thoma
    I am trying to write a platform shooter in C++ with a really good class structure for robustness. The game itself is secondary; it is the learning process of writing it that is primary. I am implementing an inheritance tree for all of the objects in my game, but I find myself unsure on some decisions. One specific issue that it bugging me is this: I have an Actor that is simply defined as anything in the game world. Under Actor is Character. Both of these classes are abstract. Under Character is the Philosopher, who is the main character that the user commands. Also under Character is NPC, which uses an AI module with stock routines for friendly, enemy and (maybe) neutral alignments. So under NPC I want to have three subclasses: FriendlyNPC, EnemyNPC and NeutralNPC. These classes are not abstract, and will often be subclassed in order to make different types of NPC's, like Engineer, Scientist and the most evil Programmer. Still, if I want to implement a generic NPC named Kevin, it would nice to be able to put him in without making a new class for him. I could just instantiate a FriendlyNPC and pass some values for the AI machine and for the dialogue; that would be ideal. But what if Kevin is the one benevolent Programmer in the whole world? Now we must make a class for him (but what should it be called?). Now we have a character that should inherit from Programmer (as Kevin has all the same abilities but just uses the friendly AI functions) but also should inherit from FriendlyNPC. Programmer and FriendlyNPC branched away from each other on the inheritance tree, so inheriting from both of them would have conflicts, because some of the same functions have been implemented in different ways on the two of them. 1) Is there a better way to order these classes to avoid these conflicts? Having three subclasses; Friendly, Enemy and Neutral; from each type of NPC; Engineer, Scientist, and Programmer; would amount to a huge number of classes. I would share specific implementation details, but I am writing the game slowly, piece by piece, and so I haven't implemented past Character yet. 2) Is there a place where I can learn these programming paradigms? I am already trying to take advantage of some good design patterns, like MVC architecture and Mediator objects. The whole point of this project is to write something in good style. It is difficult to tell what should become a subclass and what should become a state (i.e. Friendly boolean v. Friendly class). Having many states slows down code with if statements and makes classes long and unwieldy. On the other hand, having a class for everything isn't practical. 3) Are there good rules of thumb or resources to learn more about this? 4) Finally, where does templating come in to this? How should I coordinate templates into my class structure? I have never actually taken advantage of templating honestly, but I hear that it increases modularity, which means good code.

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