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  • Ensuring uniqueness on a varchar greater than 255 in MYSQL/InnoDB

    - by Vijay Boyapati
    I have a table which contains HTML entries for news pages. When I initially designed it I used URL as the primary key. I've learned the error of my ways because left-joining is super slow. So I want to redesign the table with an integer (id) primary key, but still keep the rows unique based on the URL. The problem is that I've found URLs longer than 255 characters, and MySQL isn't letting my create a key on the URL. I'm using an InnoDB/UTF8 table. From what I understand it's using multiple bytes per character with a limit of 766 bytes for the key (in InnoDB). I would really love suggestions on an elegant way of keeping the rows unique based on URL, while using an integer primary key. Thanks!

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  • Adding behaviour to a set of classes

    - by devoured elysium
    I have defined an Event class: Event and all the following classes inherit from Event: SportEventType1 SportEventType2 SportEventType3 SportEventType4 Right now I will only have SportEvents but I don't know if in the future I'll want some other kind of events that doesn't even have anything to do with Sports. Later, I will want to draw some graphics with info taken from Events, and the drawing logic can be a bit complex. But, for the moment, I think I shouldn't think of how the drawing will be done and I believe that maybe it'd be better if that drawing part was not put as an integral part of the Event/SportEventX class chain. I am looking for solutions for this problem. I know I could just make Event have an instance variable(attribute, for the java crowds) pointing to something as an IDrawInterface, but that would make the Event class "assume" it will be later used for drawing. I would like to make the Event class oblivious to this if possible. Thanks!

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  • Is there anything wrong with having a few private methods exposing IQueryable<T> and all public meth

    - by Nate Bross
    I'm wondering if there is a better way to approach this problem. The objective is to reuse code. Let’s say that I have a Linq-To-SQL datacontext and I've written a "repository style" class that wraps up a lot of the methods I need and exposes IQueryables. (so far, no problem). Now, I'm building a service layer to sit on top of this repository, many of the service methods will be 1<-1 with repository methods, but some will not. I think a code sample will illustrate this better than words. public class ServiceLayer { MyClassDataContext context; IMyRepository rpo; public ServiceLayer(MyClassDataContext ctx) { context = ctx; rpo = new MyRepository(context); } private IQueryable<MyClass> ReadAllMyClass() { // pretend there is some complex business logic here // and maybe some filtering of the current users access to "all" // that I don't want to repeat in all of the public methods that access // MyClass objects. return rpo.ReadAllMyClass(); } public IEnumerable<MyClass> GetAllMyClass() { // call private IQueryable so we can do attional "in-database" processing return this.ReadAllMyClass(); } public IEnumerable<MyClass> GetActiveMyClass() { // call private IQueryable so we can do attional "in-database" processing // in this case a .Where() clause return this.ReadAllMyClass().Where(mc => mc.IsActive.Equals(true)); } #region "Something my class MAY need to do in the future" private IQueryable<MyOtherTable> ReadAllMyOtherTable() { // there could be additional constrains which define // "all" for the current user return context.MyOtherTable; } public IEnumerable<MyOtherTable> GetAllMyOtherTable() { return this.ReadAllMyOtherTable(); } public IEnumerable<MyOtherTable> GetInactiveOtherTable() { return this.ReadAllMyOtherTable.Where(ot => ot.IsActive.Equals(false)); } #endregion } This particular case is not the best illustration, since I could just call the repository directly in the GetActiveMyClass method, but let’s presume that my private IQueryable does some extra processing and business logic that I don't want to replicate in both of my public methods. Is that a bad way to attack an issue like this? I don't see it being so complex that it really warrants building a third class to sit between the repository and the service class, but I'd like to get your thoughts. For the sake of argument, lets presume two additional things. This service is going to be exposed through WCF and that each of these public IEnumerable methods will be calling a .Select(m => m.ToViewModel()) on each returned collection which will convert it to a POCO for serialization. The service will eventually need to expose some context.SomeOtherTable which wont be wrapped into the repository.

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  • Which of these methods provides for the fastest page loading?

    - by chromedude
    I am building a database in MySQL that will be accessed by PHP scripts. I have a table that is the activity stream. This includes everything that goes on on the website (following of many different things, liking, upvoting etc.). From this activity stream I am going to run an algorithm for each user depending on their activity and display relevant activity. Should I create another table that stores the activity for each user once the algorithm has been run on the activity or should I run the algorithm on the activity table every time the user accesses the site? UPDATE:(this is what is above except rephrased hopefully in an easier to understand way) I have a database table called activity. This table creates a new row every time an action is performed by a user on the website. Every time a user logs in I am going to run an algorithm on the new rows (since the users last login) in the table (activity) that apply to them. For example if the user is following a user who upvoted a post in the activity stream that post will be displayed when the user logs in. I want the ability for the user to be able to access previous content applying to them. Would it be easiest to create another table that saved the rows that have already been run over with the algorithm except attached to individual users names? (a row can apply to multiple different users)

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  • What to do when using Contract.Assert(true) and the method must return something?

    - by devoured elysium
    I have a bit of code with the following logic: //pseudo-code foreach (element in elementList) { if (element is whatever) return element; } } In theory, there is always one element that is whatever, so this method should pose no problems. In any case, I've put an assertion on the end of the method just to be sure: //pseudo-code foreach (element in elementList) { if (element is whatever) return element; } } Contract.Assert(true, "Invalid state!"); The problem is that as this method has to return something, and the compiler doesn't understand that the assertion will break the program execution. Before using Contracts, in these kind of situations, I used to throw an Exception, which solved the problem. How would you handle this with Contract.Assert()? Returning null or default(element_type) after the Contract.Assert() call knowing it will never be called and shutting up the compiler? Or is there any other more elegant way of doing this? Thanks

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  • Detect session hang and kill it

    - by Jack Juiceson
    Hi all, I have an asp.net page that runs certain algorithm and returns it's output. I was wondering what will happen and how to handle a case where the algorithm due to a bug goes into infinite loop. It will hog the cpu and other sessions will be served very slowly. I would love to have a way to tell IIS, if processing Algo.aspx takes more than 5 seconds, kill it or something like that. Thanks in advance

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  • Client-side user custom CSS single file for overriding multiple domains

    - by Cawas
    This is for using in Safari, though it could probably be used on Firefox as well. In Chrome you have to add a plugin anyway (which generally allow for custom CSS per domain), and Opera already allows this to be done without needing any CSS. But while it's for customizing on the client-side, it's also a pure CSS question. So I'm using no plugins here. So, again, I got a custom CSS code (easily) working for all domains. Now I want to get specify CSS code for each domain. All with just 1 CSS file that's being loaded by Safari. Over the web and googling, I've found two ways to supposedly do this, but none actually worked. They're both documented on userstyles.com: @-moz-document domain("your-domain.com") { }. This would be perfect, since I can have several tags like that and just choose which style will be loaded for which domain. It just doesn't work. @namespace is quite confusing and I've tried every variation I could think of. None worked.

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  • How to separate model and view with Core Data?

    - by andrewebling
    I have a subclass of UIView which draws itself based on data held in a corresponding model class, which is a subclass of NSManagedObject. The problem is, some fields in the data model (e.g. the position of the view) are already held in the view (i.e. the frame property in this case). I then have a data duplication/synchronization problem to solve. To complicate matters further, the view needs to update in response to changes made to the data model and the data model needs to be updated in responses made to the view (e.g. the user dragging it to a new location). What's the best way to solve this? Using KVO and references in both directions? Or is there a better approach?

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  • How can I get a property as an Entity in Action of Asp.Net Mvc ?

    - by Felipe
    Hi all, i'd like to know how can I get a property like an entity, for example: My Model: public class Product { public int Id { get; set; } public string Name { get; set; } public Category Category { get; set; } } View: Name: <%=Html.TextBoxFor(x => x.Name) %> Category: <%= Html.DropDownList("Category", IEnumerable<SelectListItem>)ViewData["Categories"]) %> Controller: public ActionResult Save(Product product) { /// produtct.Category ??? } and how is the category property ? It's fill by the view ? ASP.Net MVC know how to fill this object by ID ? Thanks!

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  • Can I set ignore_dup_key on for a primary key?

    - by Mr. Flibble
    I have a two-column primary key on a table. I have attempted to alter it to set the ignore_dup_key to on with this command: ALTER INDEX PK_mypk on MyTable SET (IGNORE_DUP_KEY = ON); But I get this error: Cannot use index option ignore_dup_key to alter index 'PK_mypk' as it enforces a primary or unique constraint. How else should I set IGNORE_DUP_KEY to on?

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  • What's wrong with foreign keys?

    - by kronoz
    I remember hearing Joel mention in the podcast that he'd barely ever used a foreign key (if I remember correctly). However, to me they seem pretty vital to avoid duplication and subsequent data integrity problems throughout your database. Do people have some solid reasons as to why (to avoid a discussion in lines with SO principals)? Edit: "I've yet to have a reason to create a foreign key, so this might be my first reason to actually set up one."

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  • What CSS do I need to make my site more responsive?

    - by user2938757
    My site is: http://library.skybundle.com I feel like I almost have a responsive site. I did all the CSS styling myself. It is a Wordpress site but I completely edited the CSS of the original theme, so it is night-and-day different than it used to be. The original theme was mostly just for a canvas for me to work with, since I am not an expert in PHP and we wanted a Wordpress site for easy editing later on. Thanks to stackoverflow, I now have a footer that sticks to the bottom of every page and everything mostly looks good -- the way we want it anyway. The only thing missing now is the we want browser windows on MOBILE devices, such as on an iPhone, to automatically adjust the layout of the content in the body (wrapper). For example, on the main page (library.skybundle.com), I would like those two big icons two become vertically aligned as soon as the browser window sizes to a small, mostly vertical size, like that of a mobile phone. Take this site, for example: http://freedomsoundproductions.securesb.net/ This is what we would like it to do. So one a page with a sidebar, the content to the right of the sidebar should basically jump into the same "column" as the left sidebar and form one single long column. Just like in the example site above. This should all be possible via CSS. People in other forums seem to want me to use jQuery and stuff, but I can only use CSS, and I know that this must be possible without having to resort to jQuery, HTML, or other code.

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  • Why can't I create an abstract constructor on an abstract C# class?

    - by Anthony D
    I am creating an abstract class. I want each of my derived classes to be forced to implement a specific signature of constructor. As such, I did what I would have done has I wanted to force them to implement a method, I made an abstract one. public abstract class A { abstract A(int a, int b); } However I get a message saying the abstract modifier is invalid on this item. My goal was to force some code like this. public class B : A { public B(int a, int b) : base(a, b) { //Some other awesome code. } } This is all C# .NET code. Can anyone help me out? Update 1 I wanted to add some things. What I ended up with was this. private A() { } protected A(int a, int b) { //Code } That does what some folks are saying, default is private, and the class needs to implement a constructor. However that doesn't FORCE a constructor with the signature A(int a, int b). public abstract class A { protected abstract A(int a, int b) { } } Update 2 I should be clear, to work around this I made my default constructor private, and my other constructor protected. I am not really looking for a way to make my code work. I took care of that. I am looking to understand why C# does not let you do this.

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  • Ignoring (serious) errors to keep the program alive?

    - by SQuirreL bites
    One of the main things I wanted to achieve in my experimental programming language was: When errors occur (Syntax, Name, Type, etc.) keep the program running, no matter how serious or devastating it is. I know that this is probably very bad, but I just wanted something that doesn't kill itself on every error - I find it interesting what happens when a serious error occurs but the program continues. Does this "paradigm" have a name? I mean expect for How bad is it to do the above? Are there programs in use out there that just follow: "Hey, this is a fatal, unexpected error - but you know what? I don't care!"?

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  • Global variable in a recursive function how to keep it at zero?

    - by Grammin
    So if I have a recursive function with a global variable var_: int var_; void foo() { if(var_ == 3) return; else var_++; foo(); } and then I have a function that calls foo() so: void bar() { foo(); return; } what is the best way to set var_ =0 everytime foo is called thats not from within itself. I know I could just do: void bar() { var_ =0; foo(); return; } but I'm using the recursive function a lot and I don't want to call foo and forget to set var_=0 at a later date. Does anyone have any suggestions on how to solve this? Thanks, Josh

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  • C#. Where struct methods code kept in memory?

    - by maxima120
    It is somewhat known where .NET keeps value types in memory (mostly in stack but could be in heap in certain circumstances etc)... My question is - where is the code of the struct? If I have say 16 byte of data fields in the struct and a massive computation method in it - I am presuming that 16 byte will be copied in stack and the method code is stored somewhere else and is shared for all instances of the struct. Are these presumptions correct?

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  • I need to create a contest....

    - by creocare
    I'm working on a contest where users vote for contestants. Each contestant will have a bio. I was wondering what would be the best way to approach this? Should I do this in php or javascript? Should I use a database to collect data? Should I use sqlite3? If I use sqlite3 how do i install that on my mac? I'm very new to all this but I'm a quick learner. Thanks for any advice.

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  • MVC alternatives: examples of MVA & AVC?

    - by Phillip Oldham
    I'm interested in learning about the alternative patterns to Model-View-Controller, specifically the Model-View-Adapter and Application-View-Controller patterns. Google results tend to be either a high-level overview or Java-based. Can anyone either provide, or point me to, an example of these patterns in either PHP, Python or JavaScript?

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  • Add custom method to string object [closed]

    - by cru3l
    Possible Duplicate: Can I add custom methods/attributes to built-in Python types? In Ruby you can override any built-in object class with custom method, like this: class String def sayHello return self+" is saying hello!" end end puts 'JOHN'.downcase.sayHello # >>> 'john is saying hello!' How can i do that in python? Is there a normally way or just hacks?

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  • I built my rails app with sqlite and without specifying any db field sizes, Is my app now foobared for production?

    - by Tim Santeford
    I've been following a lot of good tutorials on building rails apps but I seem to be missing the whole specifying and validating db field sizes part. I love not needing to have to think about it when roughing out an app (I would have never done this with a PHP or ASP.net app). However, now that I'm ready to go to production, I think I might have done myself a disservice by not specifying field sizes as I went. My production db will be MySQL. What is the best practice here? Do I need to go through all of my migration files and specify sizes, update all the models with validation, and update all my form partial views with input max widths? or am I missing a critical step in my development process?

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  • How much to put in a Repository class?

    - by chobo
    When using the repository pattern is it recommended to have one Repository class for each database table? Would I also map one service layer class to one repository class. I'm having a hard time trying to understand how much stuff one repository or service layer class should have. Thanks!

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