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  • Why use SQL database?

    - by martinthenext
    I'm not quite sure stackoverflow is a place for such a general question, but let's give it a try. Being exposed to the need of storing application data somewhere, I've always used MySQL or sqlite, just because it's always done like that. As it seems like the whole world is using these databases, most of all software products, frameworks, etc. It is rather hard for a beginning developer like me to ask a question - why? Ok, say we have some object-oriented logic in our application, and objects are related to each other somehow. We need to map this logic to the storage logic, so we need relations between database objects too. This leads us to using relational database and I'm ok with that - to put it simple, our database rows sometimes will need to have references to other tables' rows. But why do use SQL language for interaction with such a database? SQL query is a text message. I can understand this is cool for actually understanding what it does, but isn't it silly to use text table and column names for a part of application that no one ever seen after deploynment? If you had to write a data storage from scratch, you would have never used this kind of solution. Personally, I would have used some 'compiled db query' bytecode, that would be assembled once inside a client application and passed to the database. And it surely would name tables and colons by id numbers, not ascii-strings. In the case of changes in table structure those byte queries could be recompiled according to new db schema, stored in XML or something like that. What are the problems of my idea? Is there any reason for me not to write it myself and to use SQL database instead?

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  • Organizing code, logical layout of segmented files

    - by David H
    I have known enough about programming to get me in trouble for about 10 years now. I have no formal education, though I've read many books on the subject for various languages. The language I am primarily focused on now would be php, atleast for the scale of things I am doing now. I have used some OOP classes for a while, but never took the dive into understanding principals behind the scenes. I am still not at the level I would like to be expression-wise...however my recent reading into a book titled The OOP Thought Process has me wanting to advance my programming skills. With motivation from the new concepts, I have started with a new project that I've coded some re-usable classes that deal with user auth, user profiles, database interfacing, and some other stuff I use regularly on most projects. Now having split my typical garbled spaghetti bowl mess of code into somewhat organized files, I've come into some problems when it comes to making sure files are all included when they need to be, and how to logically divide the scripts up into classes, aswell as how segmented I should be making each class. I guess I have rambled on enough about much of nothing, but what I am really asking for is advise from people, or suggested reading that focuses not on specific functions and formats of code, but the logical layout of projects that are larger than just a hobby project. I want to learn how to do things proper, and while I am still learning in some areas, this is something that I have no clue about other than just being creative, and trial/error. Mostly error. Thanks for any replies. This place is great.

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  • What is the best way to process XML sent to WCF 3.5

    - by CRM Junkie
    I have to develop a WCF application in 3.5. The input will be sent in the form of XML and the response would be sent in the form of XML as well. A ASP.NET application will be consuming the WCF and sending/receiving data in XML format. Now, as per my understanding, when consuming WCF from an ASP.NET application, we just add a reference to the service, create an object of the service, pack all the necessary data(Data Members in WCF) into the input object (object of the Data Contract) and call the necessary function. It happens that the ASP.NET application is being developed by a separate party and they are hell bent on receiving and sending data in XML format. What I can perceive from this is that the WCF will take the XML string (a single Data Member string type) as input and send out a XML string (again a single Data Member string type) as output. I have created WCF applications earlier where requests and responses were sent out in XML/JSON format when it was consumed by jQuery ajax calls. In those cases, the XML tags were automatically mapped to the different Data Members defined. What approach should I take in this case? Should I just take a string as input (basically the XML string) or is there any way WCF/.NET 3.5 will automatically map the XML tags with the Data Members for requests and responses and I would not need to parse the XML string separately?

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  • using jquery (json) to get ajax database entries in wordpress - PHP not working

    - by Matt Facer
    I'm writing a plugin for my wordpress site and am having trouble understanding the jquery ajax requests. In a nutshell, I am trying to get some user meta data loaded when the page loads. So in my javascript file I have a line: $.getJSON("http://mysite.co.uk/wp-content/plugins/myplugin/ajax/ajax.php?action=test", function(json) { // do stuff }); So the above DOES get called, but it's the PHP code I'm having trouble with. In the file ajax.php, I am making a database call, but NONE of the usual class information is available. I've tried including the admin ajax page, various other pages from my own plugin (which does work).... not sure what else to do! The database call method works OK in my plugin code.. but I guess that the ajax.php file is outside the WP framework so that's why it's not working... but I don't know how to get it IN the framework!? I just need to use the $wpdb->get_results($sql); command to get my SQL. The error returned from firebug is that I am making a call to an undefined function. Thanks for any help... $.getJSON("http://www.offbeatattractions.co.uk/wp-content/plugins/wp-geo-extended/ajax/change_location.php?action=listpoints", function(json) { alert(json.Locations.length);

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  • DropDownListFor and relating my lambda to my ViewModel

    - by Daniel Harvey
    After googling for a while I'm still drawing a blank here. I'm trying to use a ViewModel to pull and provide a dictionary to a drop down list inside a strongly typed View: <%@ Page Title="" Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="Notebook.ViewModels.CorporationJoinViewModel" %> ... <%: Html.DropDownListFor(c => c.CorpDictionary.Keys, new SelectList(Model.CorpDictionary, "Value", "Key"))%> I'm getting the error CS1061: 'object' does not contain a definition for 'CorpDictionary' and no extension method 'CorpDictionary' accepting a first argument of type 'object' could be found and the relevant bit of my ViewModel public class CorporationJoinViewModel { DB _db = new DB(); // data context public Dictionary<int, string> CorpDictionary { get { Dictionary<int, string> corporations = new Dictionary<int, string>(); int x = 0; foreach (Corporation corp in _db.Corporations) { corporations.Add(x, corp.name); } return corporations; } } I'll admit i have a pretty magical understanding of how linq is finding my ViewModel object from that lambda, and the error message is making me think it's not. Is my problem the method I'm using to pass the data? What am I missing here?

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  • Core Data - Entity Relationships Not Working as expected

    - by slimms
    I have set up my data model in xcode like so EntityA AttA1 AttA2 EntityB AttB1 AttB2 AttB3 I then set up the relationships EntityA Name: rlpToEntityB Destination: EntityB Inverse: rlpToEntityA To Many: Checked EntityB Name: rlpToEntityA Destination: EntityA Inverse: rlpToEntityB To Many: UnChecked i.e. relationship between the two where Each one of EntityA can have many EntityB's It is my understanding that if i fetch a subset of EntityB's I can then retrieve the values for the related EntityA's. I have this working so that i can retrieve the EntityB values using NSManagedObject *objMO = [fetchedResultsController objectAtIndexPath:indexPath]; strValueFromEntityB = [objMO valueForKey:@"AttB1"]; However, if I try to retrieve a related value from EntityA by doing the following strValueFromEntityA = [objMO valueForKey:@"AttA1"]; I get the error "The entity EntityB is not Key value coding-compliant for the key Atta1" Not surprisingly i suppose if i switch things around to fetch from EntityA i cannot access attributes of EntityB So it appears the defined relationshipare being ignored. Can anyone spot what i am doing wrong? I confess im very new to iPhone programming and especially to Core Data so please go easy on me and provide verbose explanations or point me in the direction a specific resource. I have downloaded the apple sample apps (Core Data Books, Top Songs and recipes) but I still can't work this out. Thanks in advance, Nev.

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  • Practical Scheme Programming

    - by Ixmatus
    It's been a few months since I've touched Scheme and decided to implement a command line income partitioner using Scheme. My initial implementation used plain recursion over the continuation, but I figured a continuation would be more appropriate to this type of program. I would appreciate it if anyone (more skilled with Scheme than I) could take a look at this and suggest improvements. I'm that the multiple (display... lines is an ideal opportunity to use a macro as well (I just haven't gotten to macros yet). (define (ab-income) (call/cc (lambda (cc) (let ((out (display "Income: ")) (income (string->number (read-line)))) (cond ((<= income 600) (display (format "Please enter an amount greater than $600.00~n~n")) (cc (ab-income))) (else (let ((bills (* (/ 30 100) income)) (taxes (* (/ 20 100) income)) (savings (* (/ 10 100) income)) (checking (* (/ 40 100) income))) (display (format "~nDeduct for bills:---------------------- $~a~n" (real->decimal-string bills 2))) (display (format "Deduct for taxes:---------------------- $~a~n" (real->decimal-string taxes 2))) (display (format "Deduct for savings:-------------------- $~a~n" (real->decimal-string savings 2))) (display (format "Remainder for checking:---------------- $~a~n" (real->decimal-string checking 2)))))))))) Invoking (ab-income) asks for input and if anything below 600 is provided it (from my understanding) returns (ab-income) at the current-continuation. My first implementation (as I said earlier) used plain-jane recursion. It wasn't bad at all either but I figured every return call to (ab-income) if the value was below 600 kept expanding the function. (please correct me if that apprehension is incorrect!)

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  • Encoding Problem with Zend Navigation using Zend Translate Spanish in XMLTPX File Special Characters

    - by Routy
    Hello, I have been attempting to use Zend Translate to display translated menu items to the user. It works fine until I introduce special characters into the translation files. I instantiate the Zend_Translate object in my bootstrap and pass it in as a translator into Zend_Navigation: $translate = new Zend_Translate( array('adapter' => 'tmx', 'content' => APPLICATION_PATH .'/languages/translation.tmx', 'locale' => 'es' ) ); $navigation->setUseTranslator($translate); I have used several different adapters (array,tmx) in order to see if that made a difference. I ended up with a TMX file that is encoded using ISO-8859-1 (otherwise that throws an XML parse error when introducing the menu item "Administrar Applicación". <?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE tmx SYSTEM "tmx14.dtd"> <tmx version="1.4"> <header creationtoolversion="1.0.0" datatype="tbx" segtype="sentence" adminlang="en" srclang="en" o-tmf="unknown" creationtool="XYZTool" > </header> <body> <tu tuid='link_signout'> <tuv xml:lang="en"><seg>Sign Out</seg></tuv> <tuv xml:lang="es"><seg>Salir</seg></tuv> </tu> <tu tuid='link_signin'> <tuv xml:lang="en"><seg>Login</seg></tuv> <tuv xml:lang="es"><seg>Acceder</seg></tuv> </tu> <tu tuid='Manage Application'> <tuv xml:lang="en"><seg>Manage Application</seg></tuv> <tuv xml:lang="es"><seg>Administrar Applicación</seg></tuv> </tu> </body> </tmx> Once I display the menu in the layout: echo $this->navigation()->menu(); It will display all menu items just fine, EXCEPT the one using special characters. It will simply be blank. NOW - If I use PHP's UTF8-encode inside of the zend framework class 'Menu' which I DO NOT want to do: Line 215 in Zend_View_Helper_Navigation_Menu: if ($this->getUseTranslator() && $t = $this->getTranslator()) { if (is_string($label) && !empty($label)) { $label = utf8_encode($t->translate($label)); } if (is_string($title) && !empty($title)) { $title = utf8_encode($t->translate($title)); } } Then it works. The menu item display correctly and all is joyful. The thing is, I do not want to modify the library. Is there some kind of an encoding setting in either zend translate or zend navigation that I am not finding? Please Help! Zend Library Version: 1.11

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  • How to form submit and show a different page in ASP.Net MVC?

    - by melaos
    hi guys i'm new to asp.net mvc.. so basically i just build up a two page app which takes the registration information of the user and post it to the database. i use a lot of jquery and ajax calls to retrieve data from the database using linq to sql stored proc object. and currently i'm stuck at one page where after the user submits the form it should redirect him to /Home/AddProduct. What i found was the error: Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster, ensure that <machineKey> configuration specifies the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.Web.HttpException: Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster, ensure that <machineKey> configuration specifies the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster. what used on my form are basically a combination of html controls, asp.net controls and some asp.net mvc type controls. i submit the form using action="/Home/ProductAdded" and after doing some googling i found i was supposed to add in the machine key but after doing so, the index page becomes unviewable. because it couldn't find the index file now. removing the action helps, but now it just doesn't go anywhere. so what am i missing here? i feel i'm missing a lot of fundamentals understanding about asp.net mvc and i don't even know how to submit a form and go to a different page here!!

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  • What is happening in this T-SQL code?

    - by Ben McCormack
    I'm just starting to learn T-SQL and could use some help in understanding what's going on in a particular block of code. I modified some code in an answer I received in a previous question, and here is the code in question: DECLARE @column_list AS varchar(max) SELECT @column_list = COALESCE(@column_list, ',') + 'SUM(Case When Sku2=' + CONVERT(varchar, Sku2) + ' Then Quantity Else 0 End) As [' + CONVERT(varchar, Sku2) + ' - ' + Convert(varchar,Description) +'],' FROM OrderDetailDeliveryReview Inner Join InvMast on SKU2 = SKU and LocationTypeID=4 GROUP BY Sku2 , Description ORDER BY Sku2 Set @column_list = Left(@column_list,Len(@column_list)-1) Select @column_list ---------------------------------------- 1 row is returned: ,SUM(Case When Sku2=157 Then Quantity Else 0 End) As [157 -..., SUM(Case ... The T-SQL code does exactly what I want, which is to make a single result based on the results of a query, which will then be used in another query. However, I can't figure out how the SELECT @column_list =... statement is putting multiple values into a single string of characters by being inside a SELECT statement. Without the assignment to @column_list, the SELECT statement would simply return multiple rows. How is it that by having the variable within the SELECT statement that the results get "flattened" down into one value? How should I read this T-SQL to properly understand what's going on?

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  • rs232 communication, general timing question

    - by Sunny Dee
    Hi, I have a piece of hardware which sends out a byte of data representing a voltage signal at a frequency of 100Hz over the serial port. I want to write a program that will read in the data so I can plot it. I know I need to open the serial port and open an inputstream. But this next part is confusing me and I'm having trouble understanding the process conceptually: I create a while loop that reads in the data from the inputstream 1 byte at a time. How do I get the while loop timing so that there is always a byte available to be read whenever it reaches the readbyte line? I'm guessing that I can't just put a sleep function inside the while loop to try and match it to the hardware sample rate. Is it just a matter of continuing reading the inputstream in the while loop, and if it's too fast then it won't do anything (since there's no new data), and if it's too slow then it will accumulate in the inputstream buffer? Like I said, i'm only trying to understand this conceptually so any guidance would be much appreciated! I'm guessing the idea is independent of which programming language I'm using, but if not, assume it is for use in Java. Thanks!

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  • log4j vs. System.out.println - logger advantages?

    - by wishi_
    Hi! I'm newly using log4j in a project. A fellow programmer told me that using System.out.println is considered bas style and that log4j is something like standard for logging matters nowadays. We do lots of JUnit testing - System.out stuff turns out to be harder to test. Therefore I began utilizing log4j for a Console controller class, that's just handling commandline parameters. // some logger config org.apache.log4j.BasicConfigurator.configure(); Logger logger = LoggerFactory.getLogger(Console.class); Category cat = Category.getRoot(); Seems to work: logger.debug("String"); Produces: 1 [main] DEBUG project.prototype.controller.Console - String I got two questions regarding this: From my basic understanding using this logger should provide me comfortable options to write a logfile with timestamps - instead of spamming the console - if debug mode is enabled at the logger? Why is System.out.println harder to test? I searched stackoverflow and found a testing recipe. So I wonder what kind of advantage I really get by using log4j.

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  • What is the relationship between Turing Machine & Modern Computer ?

    - by smwikipedia
    I heard a lot that modern computers are based on Turing machine. I just cannot build a bridge from a conceptual Turing Machine to a real modern computer. Could someone help me build this bridge? Below is my current understanding. I think the computer is a big general-purpose Turing machine. Each program we write is a small specific-purpose Turing machine. The classical Turing machine do its job based on the input and its current state inside and so do our programs. Let's take a running program (a process) as an example. We know that in the process's address space, there's areas for stack, heap, and code. A classical Turing machine doesn't have the ability to remember many things, so we borrow the concept of stack from the push-down automaton. The heap and stack areas contains the state of our specific-purpose Turing machine (our program). The code area represents the logic of this small Turing machine. And various I/O devices supply input to this Turing machine.

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  • Which LINQ expression is faster

    - by Vlad Bezden
    Hi All In following code public class Person { public string Name { get; set; } public uint Age { get; set; } public Person(string name, uint age) { Name = name; Age = age; } } void Main() { var data = new List<Person>{ new Person("Bill Gates", 55), new Person("Steve Ballmer", 54), new Person("Steve Jobs", 55), new Person("Scott Gu", 35)}; // 1st approach data.Where (x => x.Age > 40).ToList().ForEach(x => x.Age++); // 2nd approach data.ForEach(x => { if (x.Age > 40) x.Age++; }); data.ForEach(x => Console.WriteLine(x)); } in my understanding 2nd approach should be faster since it iterates through each item once and first approach is running 2 times: Where clause ForEach on subset of items from where clause. However internally it might be that compiler translates 1st approach to the 2nd approach anyway and they will have the same performance. Any suggestions or ideas? I could do profiling like suggested, but I want to understand what is going on compiler level if those to lines of code are the same to the compiler, or compiler will treat it literally. Thanks in advance for your help.

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  • GAE - Getting TypeError requiring class instance be passed to class's own method...

    - by Spencer Leland
    I'm really new to programming... I set up a class to give supporting information for Google's User API user object. I store this info in the datastore using db.model. When I call the okstatus method of my user_info class using this code: elif user_info.okstatus(user): self.response.out.write("user allowed") I get this error: unbound method okstatus() must be called with user_info instance as first argument (got User instance instead) Here is my user_info class. class user_info: def auth_ctrlr(self, user): if self.status(user) == status_allowed: return ("<a href=\"%s\">Sign Out</a>)" % (users.create_login_url("/"))) else: return ("<a href=\"%s\">Sign In or Get an Account</a>)" % (users.create_logout_url("/"))) def status(self, user): match = sub_user.gql(qu_by_user_id, user.user_id) return match.string_status def group(self, user): match = sub_user.gql(qu_by_user_id, user.user_id) grp = group_names.gql(qu_by_user_id, match.groupID) return grp def okstatus(self, user): match = self.status(user) if match == status_allowed: return True My understanding is that the argument "self" inside the method's calling arguments describes it as a child to the class. I've tried everything I can think of and can't find any related info online. Can someone please tell me what I'm doing wrong? Thanks

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  • Is it possible to convert a 40-character SHA1 hash to a 20-character SHA1 hash?

    - by ewitch
    My problem is a bit hairy, and I may be asking the wrong questions, so please bear with me... I have a legacy MySQL database which stores the user passwords & salts for a membership system. Both of these values have been hashed using the Ruby framework - roughly like this: hashedsalt = Digest::SHA1.hexdigest("--#{Time.now.to_s}--#{login}--") hashedpassword = Digest::SHA1.hexdigest("#{hashedsalt}:#{password}") So both values are stored as 40-character strings (varchar(40)) in MySQL. Now I need to import all of these users into the ASP.NET membership framework for a new web site, which uses a SQL Server database. It is my understanding that the the way I have ASP.NET membership configured, the user passwords and salts are also stored in the membership database (in table aspnet_Membership) as SHA1 hashes, which are then Base64 encoded (see here for details) and stored as nvarchar(128) data. But from the length of the Base64 encoded strings that are stored (28 characters) it seems that the SHA1 hashes that ASP.NET membership generates are only 20 characters long, rather than 40. From some other reading I have been doing I am thinking this has to do with the number of bits per character/character set/encoding or something related. So is there some way to convert the 40-character SHA1 hashes to 20-character hashes which I can then transfer to the new ASP.NET membership data table? I'm pretty familiar with ASP.NET membership by now but I feel like I'm just missing this one piece. However, it may also be known that SHA1 in Ruby and SHA1 in .NET are incompatible, so I'm fighting a losing battle... Thanks in advance for any insight.

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  • What's the best practice to setup testing for ASP.Net MVC? What to use/process/etc?

    - by melaos
    hi there, i'm trying to learn how to properly setup testing for an ASP.Net MVC. and from what i've been reading here and there thus far, the definition of legacy code kind of piques my interests, where it mentions that legacy codes are any codes without unit tests. so i did my project in a hurry not having the time to properly setup unit tests for the app and i'm still learning how to properly do TDD and unit testing at the same time. then i came upon selenium IDE/RC and was using it to test on the browser end. it was during that time too that i came upon the concept of integration testing, so from my understanding it seems that unit testing should be done to define the test and basic assumptions of each function, and if the function is dependent on something else, that something else needs to be mocked so that the tests is always singular and can be run fast. Questions: so am i right to say that the project should have started with unit test with proper mocks using something like rhino mocks. then anything else which requires 3rd party dll, database data access etc to be done via integration testing using selenium? because i have a function which calls a third party dll, i'm not sure whether to write a unit test in nunit to just instantiate the object and pass it some dummy data which breaks the mocking part to test it or just cover that part in my selenium integration testing when i submit my forms and call the dll. and for user acceptance tests, is it safe to say we can just use selenium again? Am i missing something or is there a better way/framework? i'm trying to put in more tests for regression testing, and to ensure that nothing breaks when we put in new features. i also like the idea of TDD because it helps to better define the function, sort of like a meta documentation. thanks!! hope this question isn't too subjective because i need it for my case.

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  • SQL Server Clustered Index: (Physical) Data Page Order

    - by scherand
    I am struggling understanding what a clustered index in SQL Server 2005 is. I read the MSDN article Clustered Index Structures (among other things) but I am still unsure if I understand it correctly. The (main) question is: what happens if I insert a row (with a "low" key) into a table with a clustered index? The above mentioned MSDN article states: The pages in the data chain and the rows in them are ordered on the value of the clustered index key. And Using Clustered Indexes for example states: For example, if a record is added to the table that is close to the beginning of the sequentially ordered list, any records in the table after that record will need to shift to allow the record to be inserted. Does this mean that if I insert a row with a very "low" key into a table that already contains a gazillion rows literally all rows are physically shifted on disk? I cannot believe that. This would take ages, no? Or is it rather (as I suspect) that there are two scenarios depending on how "full" the first data page is. A) If the page has enough free space to accommodate the record it is placed into the existing data page and data might be (physically) reordered within that page. B) If the page does not have enough free space for the record a new data page would be created (anywhere on the disk!) and "linked" to the front of the leaf level of the B-Tree? This would then mean the "physical order" of the data is restricted to the "page level" (i.e. within a data page) but not to the pages residing on consecutive blocks on the physical hard drive. The data pages are then just linked together in the correct order. Or formulated in an alternative way: if SQL Server needs to read the first N rows of a table that has a clustered index it can read data pages sequentially (following the links) but these pages are not (necessarily) block wise in sequence on disk (so the disk head has to move "randomly"). How close am I? :)

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  • Javascript scope chain

    - by Geromey
    Hi, I am trying to optimize my program. I think I understand the basics of closure. I am confused about the scope chain though. I know that in general you want a low scope (to access variables quickly). Say I have the following object: var my_object = (function(){ //private variables var a_private = 0; return{ //public //public variables a_public : 1, //public methods some_public : function(){ debugger; alert(this.a_public); alert(a_private); }; }; })(); My understanding is that if I am in the some_public method I can access the private variables faster than the public ones. Is this correct? My confusion comes with the scope level of this. When the code is stopped at debugger, firebug shows the public variable inside the this keyword. The this word is not inside a scope level. How fast is accessing this? Right now I am storing any this.properties as another local variable to avoid accessing it multiple times. Thanks very much!

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  • trying to draw scaled UIImage in custom view, but nothing's rendering

    - by Ben Collins
    I've created a custom view class and right now just want to draw an image scaled to fit the view, given a UIImage. I tried just drawing the UIImage.CGImage, but as others have attested to on this site (and in the docs), that renders the image upside down. So, at the suggestion of an answer I found to another question, I'm trying to draw it directly, but nothing is rendering in the view and I'm not sure why. Here's my drawing code: - (void)drawRect:(CGRect)rect { // Drawing code [super drawRect:rect]; if (self.originalImage) { [self drawImage]; } } - (void) drawImage { if (CGSizeEqualToSize(originalImage.size, self.frame.size) == NO) { CGFloat scaleFactor = 1.0; CGFloat scaledWidth = 0.0; CGFloat scaledHeight = 0.0; CGPoint thumbPoint = CGPointMake(0.0, 0.0); CGFloat widthFactor = self.frame.size.width / originalImage.size.width; CGFloat heightFactor = self.frame.size.height / originalImage.size.height; if (widthFactor < heightFactor) { scaleFactor = widthFactor; } else { scaleFactor = heightFactor; } scaledWidth = originalImage.size.width * scaleFactor; scaledHeight = originalImage.size.height * scaleFactor; if (widthFactor < heightFactor) { thumbPoint.y = (self.frame.size.height - scaledHeight) * 0.5; } else if (widthFactor > heightFactor) { thumbPoint.x = (self.frame.size.width - scaledWidth) * 0.5; } UIGraphicsBeginImageContext(self.frame.size); CGRect thumbRect = CGRectZero; thumbRect.origin = thumbPoint; thumbRect.size.width = scaledWidth; thumbRect.size.height = scaledHeight; [originalImage drawInRect:thumbRect]; self.scaledImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); } else { self.scaledImage = originalImage; } } My understanding (after studying this a bit) is that the UIGraphicsBeginImageContext function creates an offscreen for me to draw into, so now how do I render that context on top of the original one?

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  • Google's Oauth for Installed apps vs. Oauth for Web Apps

    - by burgerguy
    So I'm having trouble understanding something... If you do Oauth for Web Apps, you register your site with a callback URL and get a unique consumer secret key. But once you've obtained an Oauth for Web Apps token, you don't have to generate Oauth calls to the google server from your registered domain. I regularly use my key and token from scripts running via an apache server at localhost on my laptop and Google never says "you're not sending this request from the registered domain." It just sends me the data. Now, as I understand it, if you do Oauth for Installed Apps, you use "anonymous" instead of a secret key you got from Google. I've been thinking of just using the OAuth for Web Apps auth method, then passing that token to an installed app that has my secret code embedded in its innards. The worry is that the code could be discovered by bad people. But what's more secure... making them work for the secret code or letting them default to anonymous? What really goes bad if the "secret" is discovered when the alternative is using "anonymous" as the secret?

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  • What should every developer know about databases?

    - by Aaronaught
    Whether we like it or not, many if not most of us developers either regularly work with databases or may have to work with one someday. And considering the amount of misuse and abuse in the wild, and the volume of database-related questions that come up every day, it's fair to say that there are certain concepts that developers should know - even if they don't design or work with databases today. So: What are the important concepts that developers and other software professionals ought to know about databases? Guidelines for Responses: Keep your list short. One concept per answer is best. Be specific. "Data modelling" may be an important skill, but what does that mean precisely? Explain your rationale. Why is your concept important? Don't just say "use indexes." Don't fall into "best practices." Convince your audience to go learn more. Upvote answers you agree with. Read other people's answers first. One high-ranked answer is a more effective statement than two low-ranked ones. If you have more to add, either add a comment or reference the original. Don't downvote something just because it doesn't apply to you personally. We all work in different domains. The objective here is to provide direction for database novices to gain a well-founded, well-rounded understanding of database design and database-driven development, not to compete for the title of most-important.

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  • java 2D and swing

    - by user384706
    Hi, I have trouble understanding a fundamental concept in Java 2D. To give a specific example: One can customize a swing component via implementing it's own version of the method paintComponent(Graphics g) Graphics is available to the body of the method. Question: What is exactly this Graphics object, I mean how it is related to the object that has the method paintComponent? Ok, I understand that you can do something like: g.setColor(Color.GRAY); g.fillOval(0, 0, getWidth(), getHeight()); To get a gray oval painted. What I can not understand is how is the Graphics object related to the component and the canvas. How is this drawing actually done? Another example: public class MyComponent extends JComponent { protected void paintComponent(Graphics g) { System.out.println("Width:"+getWidth()+", Height:"+getHeight()); } public static void main(String args[]) { JFrame f = new JFrame("Some frame"); f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); f.setSize(200, 90); MyComponent component = new MyComponent (); f.add(component); f.setVisible(true); } } This prints Width:184, Height:52 What does this size mean? I have not added anything to the frame of size(200,90). Any help on this is highly welcome Thanks

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  • Ruby on Rails: how to get error messages from a child resource displayed?

    - by randombits
    I'm having a difficult time understanding how to get Rails to show explicitly the error messages that a child resource is failing on when I render an XML template. Hypothetically, I have the following classes: class School < ActiveRecord::Base has_many :students validates_associated :students end class Student < ActiveRecord::Base belongs_to :school validates_format_of :email, :with => /^([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})$/i, :message => "You must supply a valid email" end Now, in the controller, let's say we want to build a trivial API to allow us to add a new School with a student in it (again, I said, it's a terrible example, but plays its role for the purpose of the question) class SchoolsController < ApplicationController def create @school = School.new @student = school.students.build @student.email = "bad@email" respond_to do |format| if @school.save # some code else format.xml { render :xml => @school.errors, :status => :unprocessable_entity } end end end end Now the validation is working just fine, things die because the email doesn't match the regex that's set in the validates_format_of method in the Student class. However the output I get is the following: <?xml version="1.0" encoding="UTF-8"?> <errors> <error>Students is invalid</error> </errors> I want the more meaningful error message that I set above with validates_format_of to show up. Meaning, I want it to say: <error>You must supply a valid email</error> What am I doing wrong for that not to show up?

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  • Types issue in F#

    - by Andry
    Hello! In my ongoing adventure deep diving into f# I am understanding a lot of this powerful language but there are things that I still do not understand so clearly. One of the most important issues I need to master is types. Well the book I am reading is very straight forward and introduces entities and main functionalities with a direct approach. The first thing I could get start with is types. It introduces the main types as list, option, tuples, and so on... It is clearly underlined that all these types are IMMUTABLE for many reasons regarding functional programming and data consistance in functional programing. Well, no problems until now... But now I am getting started with Concrete Types... Well... I have problems in managing with types like list, option, tuples, types created through new operator and concrete types created using type keyword (for abbreviations, concrete types...). So my question is: how can I efficently catalogue/distinguish all types of data in f#???? I can create a perfect separation among types in C#, VB.NET... FOr example in VB.NET there are value and reference types while in C# there are only references and also int, double are treated as objects (they are objects while in VB.NET a value type is not a object and there is a split in types for this reason). Well in F# I cannot create such differences among types in the language. Can you help me? I hope I was clear.

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