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• How can an SQL query return data from multiple tables

  - by Fluffeh

  I would like to know how to get data from multiple tables in my database, what types of methods are there to do this, what are joins and unions and how are they different from one another? When should I use each one compared to the others? I am planning to use this in my (for example - PHP) application, but don't want to run multiple queries against the database, what options do I have to get data from multiple tables in a single query? Note: I am writing this as I would like to be able to link to a well written guide on the numerous questions that I constantly come across in the PHP queue, so I can link to this for further detail when I post an answer. The answers cover off the following: Part 1 - Joins and Unions Part 2 - Subqueries Part 3 - Tricks and Efficient Code

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• C++ Memory allocation question involving vectors

  - by TheFuzz

  vector< int > vect; int *int_ptr = new int(10); vect.push_back( *int_ptr ); I under stand that every "new" needs to be followed by a "delete" at some point but does the clear() method clean this memory? What about this method of doing the same thing: vector< int > vect; int int_var = 10; vect.push_back( int_var ); From what I understand, clear() calls the variables destructors, but both vect.push_back() methods in this example push an object on the vector, not a pointer. so does the first example using an int pointer need something other than clear() to clean up memory?

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• android: getting rid of "warning: unmappable character for encoding ascii"

  - by Lo'oris

  I'm compiling using android tools without eclipse. I compile launching "ant debug" from command line. I have found many many instructions around the web about how to remove with annoying warning, but I haven't been able to make any of them work. I've tried -D option, I've tried randomly tweaking build.* files, I've tried exporting an environment variable... nothing. I guess some of these methods just don't work, and some others would work but I've been doing them incorrectly. Anything is possible and I can't stand it any more: any advice on how to do it?

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• Java: How to get Unicode name of a character (or its type category)?

  - by java.is.for.desktop

  Hello, everyone! The Character class in Java defines methods which check a given char argument for equality with certain Unicode chars or for belonging to some type category. These chars and type categories are named. As stated in given javadoc, examples for named chars are HORIZONTAL TABULATION, FORM FEED, ...; example for named type categories are SPACE_SEPARATOR, PARAGRAPH_SEPARATOR, ... However, being byte or int values instead of enums, the name of these types are "hidden" at runtime. So, is there a possibility to get characters' and/or type categories' names at runtime?

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• Any good class diagram editors out there for Java (not UML)

  - by user85116

  I'm looking for an editor that can create class diagrams, similar to the typical UML class diagram, but specifically for java (so using java terminology; instead of terms like "generalization, realization etc", we use the java equivalents "interface, abstract class, extends etc"). I've looked into UML several times, but each time I've been turned off by the shear amount of "stuff" that comes with UML. I just want to be able to model my java classes quickly and intuitively, without getting bogged down by all the cruft that comes with UML. Preferably, it would come with a source reader that can keep the diagram up to date, and with a few nice features like "show only public methods in this class" etc. As well, it would automatically "know" about the classes in the standard java library, and possibly even be able to read classes from jars. Performance is also a big thing for me, I don't like having to wait 2 seconds for a popup menu to appear, or watch the diagram jerk crazily while resizing an element in the model. What do you think, am I asking too much?

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• Can we change <input type="file"> style?

  - by learner.php

  I tried to change the HTML form, input type file. Here is my code: HTML, form id = form <input class="upload_file" type="file" id="file" name="file" /> .CSS I tried both: .upload_button{ background: url('../images/upload_btn_bg.png') no-repeat; width: 200px; height: 40px; } #form input[type=file]{ background: url('../images/upload_btn_bg.png') no-repeat; width: 200px; height: 40px; } None of both of those methods works. I did see from some website, like facebook, youtube, google or twitter, they have different style. Wonder how they do it.

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• how to interpret testng console log message for passing tests?

  - by Kunal Cholera

  I ran testng tests for my test classes, I get the following three types of log output when I run the passing tests. I am using org.testng.AssertJUnit.assertTrue() methods in my tests. [testng] PASSED: testMethod1 on null(test.foo.bar.Class1) [testng] PASSED: testMethod2 on Default test name(test.foo.bar.jar.Class2) [testng] PASSED: testMethod3 Can any one please tell me why for some tests it says "on null" for some it says "on Default test name ... " and for some it does not say anything on the console output. Specifically I want to make it consistent message. Environment : linux Testng framework : 6.3.2beta please advise. thanks.

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• Annotation based data structure visualization - are there similar tools out there?

  - by Helper Method

  For a project at university I plan to build an annotation based tool to visualize/play around with data structures. Here's my idea: Students which want to try out their self-written data structures need to: mark the type of their data structures using some sort of marker annotation e.g. @List public class MyList { ... } so that I know how to represent the data structure need to provide an iterator so that I can retrieve the elements in the right order need to annotate methods for insertion and removal, e.g. @add public boolean insert(E e) { ... } so that I can "bind" that method to some button. Do similar applications exist? I googled a little bit around but didn't find anything like that.

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• What is the difference between the * and the & operators in c programming?

  - by Wesley

  I am just making sure I understand this concept correctly. With the * operator, I make a new variable, which is allocated a place in memory. So as to not unnecessarily duplicate variables and their values, the & operator is used in passing values to methods and such and it actually points to the original instance of the variable, as opposed to making new copies...Is that right? It is obviously a shallow understanding, but I just want to make sure I am not getting them mixed up. Thanks!

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• Using Java method to display HTML code

  - by javArc

  Hey folks, ok so this is my problem, I need to display HTML code in a jsp, which wouldn't be a problem, except a requirement for this project is that we place all the code in a public class file and have seperate methods for each chunk(header, sidebar footer, etc). Now here's where i'm confused: "Your method should take the PrintWriter as a parameter to print out each line of HTML, and should have a return type of void" What does that mean? How do I pass the PrintWriter into a method? Does this make sense to anyone?

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• Class views in Django

  - by Sebastjan Trepca

  Django view points to a function, which can be a problem if you want to change only a bit of functionality. Yes, I could have million keyword arguments and even more if statements in the function, but I was thinking more of an object oriented approach. For example, I have a page that displays a user. This page is very similar to page that displays a group, but it's still not so similar to just use another data model. Group also has members etc... One way would be to point views to class methods and then extend that class. Has anyone tried this approach or has any other idea?

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• Making linq avoid using in memory filtering where possible

  - by linqmonkey

  Consider the these two LINQ2SQL data retrieval methods. The first creates a 'proper' SQL statement that filters the data, but requires passing the data context into the method. The second has a nicer syntax but loads the entire list of that accounts projects, then does in memory filtering. Is there any way to preserve the syntax of the second method but with the performance advantage of the first? public partial class Account { public IQueryable<Project> GetProjectsByYear(LinqDataContext context, int year) { return context.Projects.Where(p => p.AccountID==this.AccountID && p.Year==year).OrderBy(p => p.ProjectNo) } public IQueryable<Project> GetProjectsByYear(int year) { return this.Projects.Where(p => p.Year==year).OrderBy(p => p.ProjectNo).AsQueryable() } }

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• Accessing facebook sdk result Object using .NET 3.5 API?

  - by John K

  Consider the following in .NET 3.5 (using the Bin\Net35\Facebook*.dll assemblies): using Facebook; var app = new FacebookApp(); var result = app.Get("me"); // want to access result properties with no dynamic ... in the absence of the C# 4.0 dynamic keyword this provides only generic object members. How best should I access the facebook properties of this result object? Are there helper or utility methods or stronger types in the facebook C# SDK, or should I use standard .NET reflection techniques?

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• Int property in class definition

  - by Daniel I-S

  I have the following class structure for custom UITableViewCells: NumericEntryCell - Contains method for controlling max value that can be entered into a textbox. SliderCell - inherits from NEC and contains methods for handling slider-control of textbox value TextOnlyCell - just contains a textbox CellA - inherits from SliderCell and has a max value of 28 CellB - inherits from TextOnlyCell and has a max value of 150. I want NumericEntryCell to contain a definition for a property that contains the maxValue. I want to be able to set a value for this in the initialize method of a child class (CellA or CellB). Currently I have an int maxValue declared in the interface of NEC. I declare a property for this with @property int maxValue and @synthesize it within the .m file. However, attempting to modify this property's value from CellA or CellB's initialize method has no effect - when I hit a breakpoint in the NEC method that uses this value, its value is always zero. How can I get this to work?

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• Programming terms - field, member, properties (C#)

  - by Petr

  Hi, I was trying to find meaning of this terms but especially due to language barrier I was not able to understand what they are used for. I assume that "field" is variable (object too?) in the class while "property" is just an object that returns specific value and cannot contain methods etc. By "member" I understand any object that is declared on the class level. But these are just my assumptions based on commented code samples where some careful programmers used "property region" etc. I would really appreciate if someone could explain it to me.

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• NoMethodError using Memcached Sinatra-style

  - by sevennineteen

  I've just installed Memcached on my Mac and updated my Sinatra app configuration as described in Heroku's documentation, but I'm getting a NoMethodError when trying to use the hash-based syntax they specify: >> CACHE['color'] = 'blue' >> CACHE['color'] Using explicit get and set methods as below seems to work fine. >> CACHE.set('color', 'blue') >> CACHE.get('color') If necessary I can use the latter syntax, but the former seems more elegant. I haven't tested this on Heroku's environment since I'd like whatever implementation I use to work on my local environment as well. Thanks!

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• Why I should use an N-Tier Approach When using an SqlDatasource is ALOT EASIER ?

  - by The_AlienCoder

  When it comes to web development I have always tried to work SMART not HARD. So for along time My Aproach to interacting with databases in my AspNet projects has been this : 1) Create my stored procedures 2) Drag an SQLDatasource control on my aspx page 3) Bind a DataList Control to my SQLDatasource 4) Insert, Update & Delete by using my Datalist or programmatically using built in SQLDatasource methods e.g MySqlDataSource.InsertParameters["author"].DefaultValue = TextBox1.Text; MySqlDataSource.Insert(); Recently however I got a relatively easy web project. So I decided to employ a 3-tier Model...But I got exhausted halfway and just didnt seem worth it ! It seemed like I was working too HARD for a project that could have been easily accomplished by a couple of SqlDataSource Controls. So Why Is the N-Tier Model better than my Approach? Has it anything to do with performance? What are the advantages of the ObjectDataSource control over the SqlDataSource Control?

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• How to notify ViewController on parse end with multiple ViewControllers using a single parser.

  - by objneodude

  Hello, I have created a RSS parser and 3 TableViews and it parses the RSS files fine but I don't know how to notify the TableViewController when parsing has ended so it can update the view. The TableViewController initiates the parser and the parsing of a feed. parser = [[RSSParser alloc] initWithURL:@"http://randomfeed.com"]; I can access the single feed items like [parser feedItems]; In parser.m i have implemented the delegate methods of NSXMLParser: - (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qualifiedName attributes:(NSDictionary *)attributeDict - (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string - (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName - (void)parserDidEndDocument:(NSXMLParser *)parser So how do i get parserDidEndDocument to notify my controllers so i can add the data to the tableview. Cheers from a obj-c beginner.

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• StructureMap: How can i unit test the registry class?

  - by Marius

  I have a registry class like this: public class StructureMapRegistry : Registry { public StructureMapRegistry() { For<IDateTimeProvider>().Singleton().Use<DateTimeProviderReturningDateTimeNow>(); } I want to test that the configuration is according to my intent, so i start writing a test: public class WhenConfiguringIOCContainer : Scenario { private TfsTimeMachine.Domain.StructureMapRegistry registry; private Container container; protected override void Given() { registry = new TfsTimeMachine.Domain.StructureMapRegistry(); container = new Container(); } protected override void When() { container.Configure(i => i.AddRegistry(registry)); } [Then] public void DateTimeProviderIsRegisteredAsSingleton() { // I want to say "verify that the container contains the expected type and that the expected type // is registered as a singleton } } How can verify that the registry is accoring to my expectations? Note: I introduced the container because I didn't see any sort of verification methods available on the Registry class. Idealy, I want to test on the registry class directly.

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• Rails: Thread won't affect database unless joined to main Thread

  - by hatboysam

  I have a background operation I would like to occur every 20 seconds in Rails given that some condition is true. It kicked off when a certain controller route is hit, and it looks like this def startProcess argId = self.id t = Thread.new do while (Argument.isRunning(argId)) do Argument.update(argId) Argument.markVotes(argId) puts "Thread ran" sleep 20 end end end However, this code does absolutely nothing to my database unless I call "t.join" in which case my whole server is blocked for a long time (but it works). Why can't the read commit ActiveRecords without being joined to the main thread? The thread calls methods that look something like def sample model = Model.new() model.save() end but the models are not saved to the DB unless the thread is joined to the main thread. Why is this? I have been banging my head about this for hours.

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• Linkage of namespace functions

  - by user144182

  I have a couple of methods declared at the namespace level within a header for a class: // MyClass.h namespace network { int Method1(double d); int Method2(double d); class MyClass { //... } } then defined in //MyClass.cpp int Method1(double d) { ... } int Method2(double d) { ... } This project compiles cleanly and is a dependency for a ui project which uses MyClass. The functions were previously member functions of MyClass, but were moved to namespace since it was more appropriate. My problem is the ui project complains when it gets to the linker: 1network.lib(MyClass.obj) : error LNK2001: unresolved external symbol "int __cdecl network::Method1(double)" (?INT@ds@sim@@YAHN@Z) 1network.lib(MyClass.obj) : error LNK2001: unresolved external symbol "int __cdecl network::Method2(double)" (?CINT@ds@sim@@YAHN@Z) What am I doing wrong?

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• Programmatically Untag FB Photos with Javascript

  - by Tal

  Hello! I've spent the past hour hacking away at this: I want to write a Javscript routine to programatically untag myself from photos on Facebook. Once it works, I'll run it in the Firebug console and untag myself from all Facebook photos (there's no way to do this through the GUI). I wanted to see if you guys had some advice to get me on my journey. I have a few methods in mind but haven't come too far along quite yet. I've tried an AJAX approach by creating a new HTML request and pointing it to the remove_tag URL, which looks something like this: /ajax/photo_tagging_ajax.php?pid=(PICTURE_ID)&id=(PICTURE_OWNER_ID)&subject=(SOMETHING)&name=(YOUR+NAME)&action=remove Not surprisingly, this doesn't work (yet). I've been checking the HTTP response in Firebug and it's quite different than the one when I actually untag a picture. It's not even sending a POST request. Will this even be possible or am I dreaming? (it's almost 4AM)

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• Kepping object in memory (iPhone SDK)

  - by Chris

  I am trying to create a UIImageView called theImageView in the touchesBegan method that I can then then move to a new location in touchesMoved. Currently I am receiving an "undeclared" error in touchesMoved where I set the new location for theImageView. What can I do to keep theImageView in memory between these two methods? - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { ... UIImageView *theImageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"image.png"]]; theImageView.frame = CGRectMake(263, 228, 193, 300); [theImageView retain]; ... } - (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event { ... theImageView.frame = CGRectMake(300, 300, 193, 300); ... }

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• Do AOP violate layered architecture for enterprise apps?

  - by redzedi

  The question(as stated in the title) comes to me as recently i was looking at Spring MVC 3.1 with annotation support and also considering DDD for an upcoming project. In the new Spring any POJO with its business methods can be annotated to act as controller, all the concerns that i would have addressed within a Controller class can be expressed exclusively through the annotations. So, technically i can take any class and wire it to act as controller , the java code is free from any controller specific code, hence the java code could deal with things like checking security , starting txn etc. So will such a class belong to Presentation or Application layer ?? Taking that argument even further , we can pull out things like security, txn mgmt and express them through annotations , thus the java code is now that of the domain object. Will that mean we have fused together the 2 layers? Please clarify

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• Save Values AUTOMATICALLY with NSUserDefaults

  - by Edouard Tarter

  I have an app with two UITextFields, where the user enters an integer, and then a method is called with the values the user enters. But when I completely close the app, the values are deleted. I want to change it to save the value the user entered when it closes, and loads it up when the app is re-opened. I tried this with NSUserDefault, and it worked fine (with save and load button), but I want it to make it automatically, without pressing any buttons. I saw some other people do it with the basic methods in the AppDelegate.m, but I don't know anything about that, therefore I didn't understand it at all. I saw MANY tutorials online, but I didn't understand any of them, please help, and give a detailed answer, thanks :)

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