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  • Which layer should create DataContext?

    - by Kevin
    I have a problem to decide which layer in my system should create DataContext. I have read a book, saying that if do not pass the same DataContext object for all the database updates, it will sometimes get an exception thrown from the DataContext. That's why i initially create new instance of DataContext in business layer, and pass it into data access layer. So that the same datacontext is used for all the updates. But this lead to one design problem, if i wanna change my DAL to Non-LinqToSQL in future, i need to re-write the code in business layer as well. Please give me some advice on this. Thanks. Example code 'Business Layer Public Sub SaveData(name As String) Using ts AS New TransactionScope() Using db As New MyDataContext() DAL.Insert(db,name) DAL.Insert(db,name) End Using ts.Complete() End Using End Sub 'Data Access Layer Public Sub Insert(db as MyDataContext,name As string) db.TableAInsert(name) End Sub

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  • PRoblem with converting form_tag in rails

    - by Gigg
    I am new to ruby and rails and I am having a problem from Beggining Ruby on Rails Ecommerce. (Yes, its an old book). I have these 2 code sets for a view: new.html.erb: <%= form_tag :action= 'create' do -% <%= render :partial = 'form' % <%= submit_tag 'Create' % <%= end -% <% link_to 'Back', :action = 'index' % _form.html.erb: <% error_messages_for 'supplier' % First Name Last Name But It wont show although I added the do option. It keeps giving me this error: C:/rails/emporium/app/views/admin/supplier/new.html.erb:1: syntax error, unexpected ')' ...orm_tag :action= 'create' do ).to_s) ... ^ C:/rails/emporium/app/views/admin/supplier/new.html.erb:4: syntax error, unexpected keyword_end ; @output_buffer.concat(( end ).to_s) ^ C:/rails/emporium/app/views/admin/supplier/new.html.erb:5: syntax error, unexpected tIVAR, expecting ')' @output_buffer.concat "\n" ^ C:/rails/emporium/app/views/admin/supplier/new.html.erb:7: syntax error, unexpected keyword_ensure, expecting keyword_end C:/rails/emporium/app/views/admin/supplier/new.html.erb:9: syntax error, unexpected $end, expecting ')' Can anyone suggest how I fix this since I have not fould a google answer yet. Thanks Gigg

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  • Python: Filter a dictionary

    - by Adam Matan
    Hi, I have a dictionary of points, say: >>> points={'a':(3,4), 'b':(1,2), 'c':(5,5), 'd':(3,3)} I want to create a new dictionary with all the points whose x and y value is smaller than 5, i.e. points 'a', 'b' and 'd'. According to the the book, each dictionary has the items() function, which returns a list of (key, pair) tuple: >>> points.items() [('a', (3, 4)), ('c', (5, 5)), ('b', (1, 2)), ('d', (3, 3))] So I have written this: >>> for item in [i for i in points.items() if i[1][0]<5 and i[1][1]<5]: ... points_small[item[0]]=item[1] ... >>> points_small {'a': (3, 4), 'b': (1, 2), 'd': (3, 3)} Is there a more elegant way? I was expecting Python to have some super-awesome dictionary.filter(f) function... Adam

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  • C++ Static array vs. Dynamic array?

    - by user69514
    What is the difference between a static array and a dynamic array in C++? I have to do an assignment for my class and it says not to use static arrays, only dynamic arrays. I've looked in the book and online, but I don't seem to understand. I thought static was created at compile time and dynamic at runtime, but I might be mistaken this with memory allocation. Can you explain to me the difference between static array and dynamic array in C++? Thnaks.

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  • struct function

    - by gcc
    typedef struct phoneEntry { struct phoneEntry* next; char* info; char* number; } phoneEntry; typedef struct contactEntry { struct contactEntry* next; char* name; char* surname; struct phoneEntry* phoneList; } contactEntry; I want write a function that add a new contact to the phone book using given name and surname.(please, Note that a new contact should be located in the proper location which ensures the alphabetical ordering of the contacts.) void addContact(contactEntry** phoneBook, char* name, char* surname) { } I tried to write ,but ,unfortunetely, I cannot question is that there are any person who can help me.

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  • Entity Relationship Model: Ternary Relationships

    - by Ethan
    Hi, I am trying to understand why this statement in the book is wrong: "given a C entity, there is at most one related A entity and at most one related B entity". Is it that it doesn't apply to a specific kind of relationship?? So, if I have an example of a student who is in attendance to a course with a type of subject. The entities are student, attendance, course and subject. Student makes attendance in a room. Also, a student can make attendance for a subject. Does this example apply to the statement? Thanks for your time.

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  • myth about factory pattern

    - by leiz
    This has bothered me for awhile, and I have no clues if this is a myth. It seems that a factory pattern can ease the pain of adding a dependency for a class. For example, in a book, it has something like this Suppose that you have a class named Order. Initially it did not depend on anything. Therefore you didn't bother using a factory to create Order objects and you just used plain new to instantiate the objects. However, you now have a requirement that Order has to be created in association with a Customer. There are million places you need to change to add this extra parameter. If only you had de?ned a factory for the Order class, you would have met the new requirement without the same pain. How is this not same pain as adding an extra parameter to the constructor? I mean you would still need to provide an extra argument for the factory and that is also used by million places, right?

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  • OOP Design Question - Where/When do you Validate properties?

    - by JW
    I have read a few books on OOP DDD/PoEAA/Gang of Four and none of them seem to cover the topic of validation - it seems to be always assumed that data is valid. I gather from the answers to this post (http://stackoverflow.com/questions/1651964/oop-design-question-validating-properties) that a client should only attempt to set a valid property value on a domain object. This person has asked a similar question that remains unanswered: http://bytes.com/topic/php/answers/789086-php-oop-setters-getters-data-validation#post3136182 So how do you ensure it is valid? Do you have a 'validator method' alongside every getter and setter? isValidName() setName() getName() I seem to be missing some key basic knowledge about OOP data validation - can you point me to a book that covers this topic in detail? - ie. covering different types of validation / invariants/ handling feedback / to use Exceptions or not etc

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  • Pylons/Routes Did url_for() change within templates?

    - by Charles Merram
    I'm getting an error: GenerationException: url_for could not generate URL. Called with args: () {} from this line of a mako template: <p>Your url is ${h.url_for()}</p> Over in my helpers.py, I do have: from routes import url_for Looking at the Routes-1.12.1-py2.6.egg/routes/util.py, I seem to go wrong about line it calls _screenargs(). This is simple functionality from the Pylons book. What silly thing am I doing wrong? Was there a new url_current()? Where?

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  • Creating get/set method dynamically in javascript

    - by portoalet
    I am trying to create a UserDon object, and trying to generate the get and set methods programmatically ( based on Pro Javascript book by John Resig page 37 ), and am testing this on Firefox 3.5 The problem is: in function UserDon, "this" refers to the window object instead of the UserDon object. So after calling var userdon = new UserDon(...) I got setname and getname methods created on the window object (also setage and getage). How can I fix this? function UserDon( properties ) { for( var i in properties ) { (function(){ this[ "get" + i ] = function() { return properties[i]; }; this[ "set" + i ] = function(val) { properties[i] = val; }; })(); } } var userdon = new UserDon( { name: "Bob", age: 44 });

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  • Learn mp3 format and audio signal processing

    - by Shankhoneer Chakrovarty
    I am trying to learn the following things: How mp3 file looks like internally? I found this: http://mpgedit.org/mpgedit/mpeg_format/MP3Format.html but it seems old. Is there any recent changes to the format? I couldnt find any. How to open a mp3 file in java and look for bytes? I tried using audiostream but I am getting a lot of zeros and signed short integers which nowhere resemble the header/body format as mentioned in the above link. Am I wrong in interpreting the bytes? How to get amplitude, frequency and pitch of a mp3 file? No idea. Can you please suggest some book or tutorial? Can you please help me in getting the solution for the above questions? I am sorry if some questions appear to be naive, I am a just begun to learn mp3. Thanks

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  • python __getattr__ help

    - by Stefanos Tux Zacharakis
    Reading a Book, i came across this code... # module person.py class Person: def __init__(self, name, job=None, pay=0): self.name = name self.job = job self.pay = pay def lastName(self): return self.name.split()[-1] def giveRaise(self, percent): self.pay = int(self.pay *(1 + percent)) def __str__(self): return "[Person: %s, %s]" % (self.name,self.pay) class Manager(): def __init__(self, name, pay): self.person = Person(name, "mgr", pay) def giveRaise(self, percent, bonus=.10): self.person.giveRaise(percent + bonus) def __getattr__(self, attr): return getattr(self.person, attr) def __str__(self): return str(self.person) It does what I want it to do, but i do not understand the __getattr__ function in the Manager class. I know that it Delegates all other attributes from Person class. but I do not understand the way it works. for example why from Person class? as I do not explicitly tell it to. person(module is different than Person(class) Any help is highly appreciated :)

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  • what architecture for implementing a richtext editor?

    - by genesys
    Hi! Can someone give me some hints on how a clean implementation (designwise) of a richtext editor could look like that allows for things like setting fonts, setting character colors and so on? And when and how are characters rendered? are characters rendered only once and the bitmap representation is cached? Is there any article or book covering what software design would be appropriate for that? background is that we're working on a text editing software for a language that cannot be displayed with unicode any hint is appreciated! thanks!

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  • asp.net mvc 2: SportsStore application: The current request for action is ambiguous

    - by dotnet-practitioner
    I am working on SportsStore example on chapter 4 from the following book and getting stuck... Pro Asp.net mvc framework I get the following error: The current request for action 'List' on controller type 'ProductsController' is ambiguous between the following action methods: System.Web.Mvc.ViewResult List() on type WebUI.Controllers.ProductsController System.Web.Mvc.ViewResult List(Int32) on type WebUI.Controllers.ProductsController .. My router code looks as follows: public static void RegisterRoutes(RouteCollection routes) { routes.MapRoute( null, // Route name "", // URL with parameters new { controller = "Products", action = "List", page=1 } ); routes.MapRoute( null, // Route name "Page{page}", // URL with parameters new { controller = "Products", action = "List" }, // Parameter defaults new { page = @"\d+" } ); } and controller code looks as follows: public ViewResult List() { return View(productsRepository.Products.ToList()); } public ViewResult List(int page) { return View(productsRepository.Products .Skip((page - 1) * PageSize) .Take(PageSize) .ToList()); } What am I missing? my url is as follows: http://localhost:1103/ or http://localhost:1103/Page1 or http://localhost:1103/Page2 thanks

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  • How to post HTML content in facebook wall using facebook api in php

    - by Elankeeran
    How to post HTML content in facebook wall using facebook api in php I have used below codes but not working $result = $facebook->api('/me/feed/','post',array( 'message' => '<h1>This is my demo Face book application!</h1>')); And I used as below code using php concatenate the HTML string $result = $facebook->api('/me/feed/','post',array( 'message' => 'This is my demo Facebook application!' . $htmlStr)); but not working and getting below error OAuthException: (#1) An unknown error occurred Any please help me.

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  • How to prepare for a Java test?

    - by Zenzen
    Ok so in two days I have a test for my dream job (well it's an internship, but still!) and for quite some time now I've been reading the SCJP Guide book in order to prepare myself. BUT seeing how slow my reading speed is I guess finding a website with some "java essentials" or "standard java test questions" and going through it in those 2 days would be a better idea. Don't misunderstand me, I do have java experience and it's "only" an internship, but we all know how programming tests look like and how tricky they can be. So are there any online resources you could recommend me? I know 2 days is not much, but well I was informed bout the test 1-2days ago.

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  • Why am I getting unexpected output trying to write a hash structure to a file?

    - by Harm De Weirdt
    I have a hash in which I store the products a customer buys (%orders). It uses the product code as key and has a reference to an array with the other info as value. At the end of the program, I have to rewrite the inventory to the updated version (i.e. subtract the quantity of the bought items) This is how I do rewrite the inventory: sub rewriteInventory{ open(FILE,'>inv.txt'); foreach $key(%inventory){ print FILE "$key\|$inventory{$key}[0]\|$inventory{$key}[1]\|$inventory{$key}[2]\n" } close(FILE); } where $inventory{$key}[x] is 0 → Title, 1 → price, 2 → quantity. The problem here is that when I look at inv.txt afterwards, I see things like this: CD-911|Lady Gaga - The Fame|15.99|21 ARRAY(0x145030c)||| BOOK-1453|The Da Vinci Code - Dan Brown|14.75|12 ARRAY(0x145bee4)||| Where do these ARRAY(0x145030c)||| entries come from? Or more important, how do I get rid of them?

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  • MCTS exam 70-526 vs 70-505

    - by doug.stanhope
    I guess this should be CW but I don't know how to post a question as such, so if anyone can help out... What I would like to know is the following: I have taken exam 70-526 a couple of years ago and I still have the training kit laying around. Now my boss wants me to prepare for the upgrade exam 70-505. Do you know if both exams are similar or otherwise put: do you think I have to get the new training kit to prepare for this exam or will the old one do? I haven't done a whole lot of Windows Forms programming these past few years so I'll have to re-learn much of what's in the book.

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  • cakePHP - ACL tutorial & SQL Error: 1104

    - by vector
    Greetings! I run into a problem/bug in production environment with SQL Error: 1104 when deploying a project secured with the ACL tutorial. The full error: SQL Error: 1104: The SELECT would examine more than MAX_JOIN_SIZE rows; check your WHERE and use SET SQL_BIG_SELECTS=1 or SET SQL_MAX_JOIN_SIZE=# if the SELECT is okay [CORE/cake/libs/model/datasources/dbo_source.php, line 666] I've build a small site, worked through the ACL tutorial from the official cake book and locally everything is spiffy. dev. setup consists of: XAMPP: myslq 5.1.33, php 5.3 cakePHP 1.2.7 prod. setup: mysql 5.0.33 php 5.2.2 One of the differences I noticed with mysql setup between local and production servers, is that SQL_BIG_SELECTS is disabled on the production server ( and I don't have privileges to change that, posted a support ticked, didn't hear anything yet) Is there anything I can do about this from my end? Thanks in advance.

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  • Real time web services

    - by daliz
    Hi everybody, I have a little (maybe the answer could require a book) question about web services and server side programming. But first, a little preamble. Recently we have seen new kind of applications & games using some kind of real-time interaction with a database, or more generally, with other users. I'm talking about shared drawing canvas, games like this , or simple chats, or the Android app "a World of Photo", where in real time you see who is online, to share your photos, etc. Now my question: Are all these apps based on classic TCP client/server architectures or is there a way to make them in a simpler way, like a web platform like LAMP? What I'm asking, in other words is: Can PHP+MySQL (or JSP, or RoR, or any other server language) provide a way to make online users communicate in real time and share data? Is there a way to do that without the ugly and heavy mechanism of temporary tables? Thank you! I hope I've been clear.

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  • Why not use javascript handlers on the body element?

    - by disown
    As an answer to the question of 'How do you automatically set the focus to a textbox when a web page loads?', Espo suggests using <body onLoad="document.getElementById('<id>').focus();"> Ben Scheirman replies (without further explanation): Any javascript book will tell you not to put handlers on the body element like that Why would this be considered bad practice? In Espos answer, an 'override' problem is illustrated. Is this the only reason, or are there any other problems? Compatibility issues?

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  • Understanding the output from svn export

    - by ThatBlairGuy
    Working on some tweaks for a build script, I noticed that the output from svn export has an 'A' in column 1 for each file exported. A C:\build\file1 A C:\build\file2 A C:\build\file3 The subversion book describes the meaning of the various columns for svnlook changes and svn status, but I'm not having much luck finding the meaning behind this one. What does the 'A' in column 1 mean? Are there any other values displayed there? Any other columns? Thanks!

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  • [Rais] OAuth with Digg API

    - by Karl
    I'm attempting to get Rails to play nice with the Digg API's OAuth. I'm using the oauth gem (ruby one, not the rails one). My code looks approximately like this: @consumer = OAuth::Consumer.new(API_KEY, API_SECRET, :scheme => :header, :http_method => :post, :oauth_callback => "http://locahost:3000", :request_token_url => 'http://services.digg.com/1.0/endpoint?method=oauth.getRequestToken', :access_token_url => 'http://services.digg.com/1.0/endpoint?method=oauth.getAccessToken', :authorize_url => 'http://digg.com/oauth/authorize') @request_token = @consumer.get_request_token session[:request_token] = @request_token.token session[:request_token_secret] = @request_token.secret redirect_to @request_token.authorize_url Which is by-the-book in terms of what the gem documentation gave me. However, Digg spits a "400 Bad Request" error back at me when @consumer.get_request_token is called. I can't figure out what I'm doing wrong. Any ideas?

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  • Help with parsing lxml

    - by Casey
    Hi To implement a college project, I need to handle XML files. For this I choose lxml after doing some research. However I can't seem to find some nice tutorial to help me get started. I can't choose most specifically which type of parsing I need to use. My XML files don't have that much data but speed is main concern, not memory. Can anyone point me to some tutorial that would help me or some book that I can lookup? I have already tried the tutorial on lxml site but that didn't help me much. Is there some small application I can look up to get a hang of parsing XML with lxml

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  • iPhone facebook connect FQL Query to get Profile URL.

    - by user306641
    Hai. I am using Face book Connect FQL Queries to extract my profile photo url that is src_big,src_small URL. But i am always getting the empty array in below delegate (void)request:(FBRequest*)request didLoad:(id)result My FQL query is. NSString* fql = [NSString stringWithFormat:@"SELECT src_big,src_small FROM photo WHERE pid IN (SELECT cover_pid FROM album WHERE owner =%lld AND name ='Profile Pictures')", session.uid]; NSDictionary* params = [NSDictionary dictionaryWithObject:fql forKey:@"query"]; [[FBRequest requestWithDelegate:self] call:@"facebook.fql.query" params:params]; But - (void)request:(FBRequest*)request didLoad:(id)result always return the empty result. Can any one please correct me if there any mistake.

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