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  • which is better, creating a view or a new table?

    - by Carson
    I have some demanding mysql queries that are needed to grap same datasets from several mysql tables. I am thinking of creating a table or view to gather all demanding columns from other tables, so as to increase performance. If I create that table, I may need to do extra insert / update / delete operation each time other tables updated. if I create view, I am worrying if the performance can be greatly improved. Because data from other tables are changing very frequently. Most likely, the view may need to be created first everytime before selecting it. Any ideas? e.g. how to cache? other extra measures I can do?

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  • MSSQL Server using multiple ID Numbers

    - by vincer
    I have an web application that creates printable forms, these forms have a unique number on them, the problem is I have 2 forms that separate numbers need to be created for them. ie) Form1- Numbered 2000000-2999999 Form2- Numbered 3000000-3999999 dbo.test2 - is my form information table Tsel - is my autoinc table for the 3000000 series numbers Tadv - is my autoinc table for the 2000000 series numbers What I have done is create 2 tables with just autoinc row (one for 2000000 series numbers and one for 3000000 series numbers), I then created a trigger to add a record to the coresponding table, read back the autoinc number and add it to my table that stores the form information including the just created autoinc number for the right series of forms. Although it does work, I'm concerned that the numbers will get messed up under load. I'm not sure the @@IDENTITY will always return the right value when many people are using the system. (I cannot have duplicates and I need to use the numbering form show above. Thanks for any help See code below. ** TRIGGER ** CREATE TRIGGER MAKEANID2 ON dbo.test2 AFTER INSERT AS SET NOCOUNT ON declare @someid int declare @someid2 int declare @startfrom int declare @test1 varchar(10) select @someid=@@IDENTITY select @test1 = (Select name1 from test2 where sysid = @someid ) if @test1 = 'select' begin insert into Tsel Default values select @someid2 = @@IDENTITY end if @test1 = 'adv' begin insert into Tadv Default values select @someid2 = @@IDENTITY end update test2 set name2=(@someid2) where sysid = @someid SET NOCOUNT OFF

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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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  • Double reversals on technology decisions

    - by Kev
    Have you ever gone through a painful switch from one technology to another, only to switch back later in a project's lifetime? Was it because the technologies evolved differently than you expected, or because of something you didn't understand about them in the first place, or because they didn't fly when it came to beta testing or production? Did you regret the switch back too?

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  • Best way to have common class shared by both C++ and Ruby?

    - by shuttle87
    I am currently working on a project where a team of us are designing a game, all of us are proficient in ruby and some (but not all) of us are proficient in c++. Initially we made the backend in ruby but we ported it to c++ for more speed. The c++ port of the backend has exactly the same features and algorithms as the original ruby code. However we still have a bunch of code in ruby that does useful things but we want it to now get the data from the c++ classes. Our first thought was that we could save some of the data structures in something like XML or redis and call that, but some of the developers don't like that idea. We don't need anything particularly complex data structures to be passed between the different parts of the code, just tuples, strings and ints. Is there any way of integrating the ruby code so that it can call the c++ stuff natively? Will we need to embed code? Will we have to make a ruby extension? If so are there any good resources/tutorials you could suggest? For example say we have this code in the c++ backend: class The_game{ private: bool printinfo; //print the player diagnostic info at the beginning if true int numplayers; std::vector<Player*> players; string current_action; int action_is_on; // the index of the player in the players array that the action is now on //more code here public: Table(std::vector<Player *> in_players, std::vector<Statistics *> player_stats ,const int in_numplayers); ~Table(); void play_game(); History actions_history; }; class History{ private: int action_sequence_number; std::vector<Action*> hand_actions; public: void print_history(); void add_action(Action* the_action_to_be_added); int get_action_sequence_number(){ return action_sequence_number;} bool history_actions_are_equal(); int last_action_size(int street,int number_of_actions_ago); History(); ~History(); }; Is there any way to natively call something in the actions_history via The_game object in ruby? (The objects in the original ruby code all had the same names and functionality) By this I mean: class MyRubyClass def method1(arg1) puts arg1 self.f() # ... but still available puts cpp_method.the_current_game.actions_history.get_action_sequence_number() end # Constructor: def initialize(arg) puts "In constructor with arg #{arg}" #get the c++ object here and call it cpp_method end end Is this possible? Any advice or suggestions are appreciated.

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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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  • Is there anything wrong with a class with all static methods?

    - by MatthewMartin
    I'm doing code review and came across a class that uses all static methods. The entrance method takes several arguments and then starts calling the other static methods passing along all or some of the arguments the entrance method received. It isn't like a Math class with largely unrelated utility functions. In my own normal programming, I rarely write methods where Resharper pops and says "this could be a static method", when I do, they tend to be mindless utility methods. Is there anything wrong with this pattern? Is this just a matter of personal choice if the state of a class is held in fields and properties or passed around amongst static methods using arguments?

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  • Is Embed Resource a good approach for a read only xml database?

    - by Nasser Hajloo
    I have an open source application (here) This application get a character or a sentence and give some unicode information about it. Iuse Unicode Character Database which provided by Unicode.org this is a XML document (130MB) At first I embed this XML to my DLL but I don't know is it a good approach or no. because DLL size growth just because of this XML document. I can use it like any other resources but usercan see it. What Should I do? What is the best pattern for this? and Why ? TIA

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  • Voting Script, Possiblity of Simplifying Database Queries

    - by Sev
    I have a voting script which stores the post_id and the user_id in a table, to determine whether a particular user has already voted on a post and disallow them in the future. To do that, I am doing the following 3 queries. SELECT user_id, post_id from votes_table where postid=? AND user_id=? If that returns no rows, then: UPDATE post_table set votecount = votecount-1 where post_id = ? Then SELECT votecount from post where post_id=? To display the new votecount on the web page Any better way to do this? 3 queries are seriously slowing down the user's voting experience

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  • PHP: Star rating system concept?

    - by Prashant
    I am using PHP/MYSQL/JQUERY. I have a site which have news section. On news details page, I want to add star rating system which will allow user to rate the news story. I am using this jquery rating system http://www.fyneworks.com/jquery/star-rating/ Now, I am not getting what will be the database structure and then what I need to code in PHP. I need what logic will be applied for this, like if 1000 people voted for the article, some given rating as 2 or 3 or1 or 5. Then Where I should be storing (db structure) this all and what I'll calculate (in php code). If someone has any article which shows this concept please provide. Please help, to understand the logic and concept of this. Thanks!

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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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  • Instantiate a javascript module only one time.

    - by Cedric Dugas
    Hey guys, I follow a module pattern where I instantiate components, however, a lot of time a component will only be instantiate one time (example: a comment system for an article). For now I instantiate in the same JS file. but I was wondering if it is the wrong approach? It kind of make no sense to instantiate in the same file and always only once. But at the same time, if this file is in the page I want to have access to my module without instantiate from elsewhere, and IF I need another instance, I just create another from elsewhere... Here is the pattern I follow: ApplicationNamespace.Classname = function() { // constructor function privateFunctionInit() { // private } this.privilegedFunction = function() { // privileged privateFunction(); }; privateFunctionInit() }; ApplicationNamespace.Classname.prototype = { Method: function(){} } var class = new ApplicationNamespace.Classname(); What do you think, wrong approach, or is this good?

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  • How to write this in better way?

    - by dario
    Hi all. Let's look at this code: IList<IHouseAnnouncement> list = new List<IHouseAnnouncement>(); var table = adapter.GetData(); //get data from repository object -> DataTable if (table.Rows.Count >= 1) { for (int i = 0; i < table.Rows.Count-1; i++) { var anno = new HouseAnnouncement(); anno.Area = float.Parse(table.Rows[i][table.powierzchniaColumn].ToString()); anno.City = table.Rows[i][table.miastoColumn].ToString(); list.Add(anno); } } return list; Is it better way to write this in less code and better fashion (must be :-) )? Maybe using labda (but let mi know how)? Thanks in advance!

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  • Why doesn't Java warn about a == "something"?

    - by Marius
    This might sound stupid, but why doesn't the Java compiler warn about the expression in the following if statement: String a = "something"; if(a == "something"){ System.out.println("a is equal to something"); }else{ System.out.println("a is not equal to something"); } I realize why the expression is untrue, but AFAIK, a can never be equal to the String literal "something". The compiler should realize this and at least warn me that I'm an idiot who is coding way to late at night.

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  • Can't declare an abstract method private....

    - by Zombies
    I want to do this, yet I can't. Here is my scenario and rational. I have an abstract class for test cases that has an abstract method called test(). The test() method is to be defined by the subclass; it is to be implemented with logic for a certain application, such as CRMAppTestCase extends CompanyTestCase. I don't want the test() method to be invoked directly, I want the super class to call the test() method while the sub class can call a method which calls this (and does other work too, such as setting a current date-time right before the test is executed for example). Example code: public abstract class CompanyTestCase { //I wish this would compile, but it cannot be declared private private abstract void test(); public TestCaseResult performTest() { //do some work which must be done and should be invoked whenever //this method is called (it would be improper to expect the caller // to perform initialization) TestCaseResult result = new TestCaseResult(); result.setBeginTime(new Date()); long time = System.currentTimeMillis(); test(); //invoke test logic result.setDuration(System.currentTimeMillis() - time); return result; } } Then to extend this.... public class CRMAppTestCase extends CompanyTestCase { public void test() { //test logic here } } Then to call it.... TestCaseResult result = new CRMAppTestCase().performTest();

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  • Many tables for many users?

    - by Seagull
    I am new to web programming, so excuse the ignorance... ;-) I have a web application that in many ways can be considered to be a multi-tenant environment. By this I mean that each user of the application gets their own 'custom' environment, with absolutely no interaction between those users. So far I have built the web application as a 'single user' environment. In other words, I haven't actually done anything to support multi-users, but only worked on the functionality I want from the app. Here is my problem... What's the best way to build a multi-user environment: All users point to the same 'core' backend. In other words, I build the logic to separate users via appropriate SQL queries (eg. select * from table where user='123' and attribute='456'). Each user points to a unique tablespace, which is built separately as they join the system. In this case I would simply generate ALL the relevant SQL tables per user, with some sort of suffix for the user. (eg. now a query would look like 'select * from table_ where attribute ='456'). In short, it's a difference between "select * from table where USER=" and "select * from table_USER".

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  • Interesting or unique types encountered?

    - by user318904
    What is the most strange or unique type you have seen in a programming language? I was thinking the other day about a "random variable", ie whenever it is evaluated it yields a random value from some domain. It would require some runtime trickery. Also I bet there can be some interesting mapping of regular expressions into a type system. It does not necessarily have to be a built in or primitive type, but some random class that implements a domain specific type won't really be interesting just unique.

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  • When/Why to use Cascading in SQL Server?

    - by Joel Coehoorn
    When setting up foreign keys in SQL Server, under what circumstances should you have it cascade on delete or update, and what is the reasoning behind it? This probably applies to other databases as well. I'm looking most of all for concrete examples of each scenario, preferably from someone who has used them successfully.

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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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  • 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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  • Correct approach to validate attributes of an instance of class

    - by systempuntoout
    Having a simple Python class like this: class Spam(object): __init__(self, description, value): self.description = description self.value = value Which is the correct approach to check these constraints: "description cannot be empty" "value must be greater than zero" Should i: 1.validate data before creating spam object ? 2.check data on __init__ method ? 3.create an is_valid method on Spam class and call it with spam.isValid() ? 4.create an is_valid static method on Spam class and call it with Spam.isValid(description, value) ? 5.check data on setters declaration ? 6.... Could you recommend a well designed\Pythonic\not verbose (on class with many attributes)\elegant approach?

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  • What is the Rule of Thumb on Exposing Encapsulated Class Methods

    - by javamonkey79
    Consider the following analogy: If we have a class: "Car" we might expect it to have an instance of "Engine" in it. As in: "The car HAS-A engine". Similarly, in the "Engine" class we would expect an instance of "Starting System" or "Cooling System" which each have their appropriate sub-components. By the nature of encapsulation, is it not true that the car "HAS-A" "radiator hose" in it as well as the engine? Therefore, is it appropriate OO to do something like this: public class Car { private Engine _engine; public Engine getEngine() { return _engine; } // is it ok to use 'convenience' methods of inner classes? // are the following 2 methods "wrong" from an OO point of view? public RadiatorHose getRadiatorHose() { return getCoolingSystem().getRadiatorHose(); } public CoolingSystem getCoolingSystem() { return _engine.getCoolingSystem(); } } public class Engine { private CoolingSystem _coolingSystem; public CoolingSystem getCoolingSystem() { return _coolingSystem; } } public class CoolingSystem { private RadiatorHose _radiatorHose; public RadiatorHose getRadiatorHose() { return _radiatorHose; } } public class RadiatorHose {//... }

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