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  • rails not recognizing project

    - by tipu
    I can create a new project using rails and I can use stuff like rails migration ... and i (correctly) get a error because the sqlite gem is missing. but when i try using rails migration ... with a project i checked out from github, it doesn't recognize that it is a rails project i get: Usage: rails new APP_PATH [options] Options: -d, [--database=DATABASE] # Preconfigure for selected database (options: mysql/oracle/postgresql/sqlite3/frontbase/ibm_db) # Default: sqlite3 -O, [--skip-active-record] # Skip Active Record files [--dev] # Setup the application with Gemfile pointing to your Rails checkout -J, [--skip-prototype] # Skip Prototype files -T, [--skip-test-unit] # Skip Test::Unit files -G, [--skip-git] # Skip Git ignores and keeps -b, [--builder=BUILDER] # Path to an application builder (can be a filesystem path or URL) [--edge] # Setup the application with Gemfile pointing to Rails repository -m, [--template=TEMPLATE] # Path to an application template (can be a filesystem path or URL) -r, [--ruby=PATH] # Path to the Ruby binary of your choice # Default: /usr/bin/ruby1.8 [--skip-gemfile] # Don't create a Gemfile and it goes on. any ideas? edit: it's probably an important detail that earlier my rails wasn't working at all. i had to cp /usr/bin/ruby to /usr/bin/local/ruby

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  • C++: static assert for const variables?

    - by shoosh
    Static asserts are very convenient for checking things in compile time. A simple static assert idiom looks like this: template<bool> struct StaticAssert; template<> struct StaticAssert<true> {}; #define STATIC_ASSERT(condition) do { StaticAssert<condition>(); } while(0) This is good for stuff like STATIC_ASSERT(sizeof(float) == 4) and: #define THIS_LIMIT (1000) ... STATIC_ASSERT(THIS_LIMIT > OTHER_LIMIT); But using #define is not the "C++" way of defining constants. C++ would have you use an anonymous namespace: namespace { const int THIS_LIMIT = 1000; } or even: static const int THIS_LIMIT = 1000; The trouble with this is that with a const int you can't use STATIC_ASSERT() and you must resort to a run-time check which is silly. Is there a way to properly solve this in current C++? I think I've read C++0x has some facility to do this...

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  • How would I code a complex formula parser manually?

    - by StormianRootSolver
    Hm, this is language - agnostic, I would prefer doing it in C# or F#, but I'm more interested this time in the question "how would that work anyway". What I want to accomplish ist: a) I want to LEARN it - it's about my ego this time, it's for a fun project where I want to show myself that I'm a really good at this stuff b) I know a tiny little bit about EBNF (although I don't know yet, how operator precedence works in EBNF - Irony.NET does it right, I checked the examples, but this is a bit ominous to me) c) My parser should be able to take this: 5 * (3 + (2 - 9 * (5 / 7)) + 9) for example and give me the right results d) To be quite frankly, this seems to be the biggest problem in writing a compiler or even an interpreter for me. I would have no problem generating even 64 bit assembler code (I CAN write assembler manually), but the formula parser... e) Another thought: even simple computers (like my old Sharp 1246S with only about 2kB of RAM) can do that... it can't be THAT hard, right? And even very, very old programming languages have formula evaluation... BASIC is from 1964 and they already could calculate the kind of formula I presented as an example f) A few ideas, a few inspirations would be really enough - I just have no clue how to do operator precedence and the parentheses - I DO, however, know that it involves an AST and that many people use a stack So, what do you think?

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  • Read whole ASCII file into C++ std::string

    - by Arrieta
    Hello, I need to read a whole file into memory and place it in a C++ std::string. If I were to read it into a char, the answer would be very simple: std::ifstream t; int lenght; t.open("file.txt", "r"); // open input file t.seekg(0, std::ios::end); // go to the end length = t.tellg(); // report location (this is the lenght) t.seekg(0, std::ios::beg); // go back to the beginning buffer = new char[length]; // allocate memory for a buffer of appropriate dimension t.read(buffer, length); // read the whole file into the buffer t.close(); // close file handle // ... do stuff with buffer here ... Now, I want to do the exact same thing, but using a std::string instead of a char. I want to avoid loops, i. e., I don't want to: std::ifstream t; t.open("file.txt", "r"); std::string buffer; std::string line; while(t){ std::getline(t, line); // ... append line to buffer and go on } t.close() any ideas?

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  • Opening a xul file in response to a toolbar extension button click

    - by Graham
    I'm currently building my first Firefox extension, and am having a little difficulty with one piece of functionality. I'd like to open a new browser tab in response to a button click on the toolbar. The new tab should contain the contents of a webpage, together with some extra buttons. At the moment I've created a separate xul file for the contents of the new tab: <?xml version="1.0"?> <?xml-stylesheet href="chrome://global/skin/" type="text/css"?> <window id="myapp-report-window" title="Example 4.5.1" xmlns:html="http://www.w3.org/1999/xhtml" xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"> <script type="application/x-javascript" src="chrome://myapp/content/main.js" /> <toolbox> <toolbar id="nav-toolbar"> <toolbarbutton label="This-is-going-to-do-some-stuff"/> </toolbar> </toolbox> <iframe id="myapp-report-frame" flex="1"/> <script type="text/javascript"> function loadPage(url){ document.getElementById('myapp-report-frame').setAttribute('src',url); } </script> </window> This xul file is launched via this javascript, referenced from the main myapptoolbar.xul: gBrowser.selectedTab = gBrowser.addTab('chrome://myapp/content/report.xul'); var newTabBrowser = gBrowser.getBrowserForTab(gBrowser.selectedTab); newTabBrowser.addEventListener("load", function(){ loadPage('http://www.somedynamicallysetwebsite.com'); }, true); The problem that I'm having is that the loadPage function is not being found, so the src attribute of the iframe is never set. I'm sure it's some silly scoping problem, but I'm very new to firefox extensions (day 2!) so any help would be much appreciated. Thanks for looking! Graham

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  • How to refresh/redraw the screen (not the program window)

    - by mohrphium
    I'm having a bit of a hard time figuring out, how to remove a drawn ellipse after it has been drawn somewhere else. I need a circle to follow my mouse all the time and this is all the program should do. I get the mousepositions and draw my circle but how can I remove the last one? #include <Windows.h> #include <iostream> void drawRect(int a1, int a2){ HDC screenDC = ::GetDC(0); //Draw circle at mouse position ::Ellipse(screenDC, a1, a2+5, a1+9, a2+14); ::ReleaseDC(0, screenDC); //::InvalidateRect(0, NULL, TRUE); //<- I tried that but then everything flickers //Also, the refresh rate is not fast enough... still some circles left } int main(void) { int a1; int a2; bool exit=false; while (exit!=true) { POINT cursorPos; GetCursorPos(&cursorPos); float x = 0; x = cursorPos.x; float y = 0; y = cursorPos.y; a1=(int)cursorPos.x; a2=(int)cursorPos.y; drawRect(a1, a2); } } I am working with graphics and all that stuff for the first time. Im kinda stuck here... once again. Thanks.

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  • How can I improve the performance of LinqToSql queries that use EntitySet properties?

    - by DanM
    I'm using LinqToSql to query a small, simple SQL Server CE database. I've noticed that any operations involving sub-properties are disappointingly slow. For example, if I have a Customer table that is referenced by an Order table, LinqToSql will automatically create an EntitySet<Order> property. This is a nice convenience, allowing me to do things like Customer.Order.Where(o => o.ProductName = "Stopwatch"), but for some reason, SQL Server CE hangs up pretty bad when I try to do stuff like this. One of my queries, which isn't really that complicated takes 3-4 seconds to complete. I can get the speed up to acceptable, even fast, if I just grab the two tables individually and convert them to List<Customer> and List<Order>, then join then manually with my own query, but this is throwing out a lot of what makes LinqToSql so appealing. So, I'm wondering if I can somehow get the whole database into RAM and just query that way, then occasionally save it. Is this possible? How? If not, is there anything else I can do to boost the performance besides resorting to doing all the joins manually? Note: My database in its initial state is about 250K and I don't expect it to grow to more than 1-2Mb. So, loading the data into RAM certainly wouldn't be a problem from a memory point of view. Update Here are the table definitions for the example I used in my question: create table Order ( Id int identity(1, 1) primary key, ProductName ntext null ) create table Customer ( Id int identity(1, 1) primary key, OrderId int null references Order (Id) )

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  • Is learning C++ a good idea?

    - by chang
    The more I hear and read about C++ (e.g. this: http://lwn.net/Articles/249460/), I get the impression, that I'd waste my time learning C++. I some wrote network routing algorithm in C++ for a simulator, and it was a pain (as expected, especially coming from a perl/python/Java background ...). I'm never happy about giving up on some technology, but I would be happy, if I could limit my knowledge of C-family languages to just C, C# and Objective-C (even OS Xs Cocoa, which is huge and takes a lot of time to learn looks like joy compared to C++ ...). Do I need to consider myself dumb or unwilling, just because I'm not partial to the pain involved learning this stuff? Technologies advance and there will be options other than C++, when deciding on implementation languages, or not? And for speed: If speed were that critical, I'd go for a plain C implementation instead, or write C extensions for much more productive languages like ruby or python ... The one-line version of the above: Will C++ stay such a relevant language that every committed programmer should be familiar with it? [ edit / thank you very much for your interesting and useful answers so far .. ] [ edit / .. i am accepting the top-rated answer; thanks again for all answers! ]

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  • Android shared library which is not JNI based

    - by Mondain
    I am developing a library for Android applications which does not use native code (JNI). I have tried suppling the library as an external jar in my Android projects but this method does not include the library contents in the apk and thus throws class not found errors when run in the emulator or device. I have also tried creating the library as an Android project in itself and this does work, but only for public static properties (not methods). With the library and application both being in separate apk's I can see that the VM notices references to the library and can read some properties, but when an attempt to instantiate a class in the library is executed I get class not found even though I can read the public static properties from it (very frustrating!!). I realize that Davlik byte code is not the same as Java byte code but I am having trouble even finding good information about how to solve what would seem to be a very simple issue in Android. I am looking into the old PlatformLibrary stuff right now but I am not convinced this will work either since the sample has been removed from the Android site :( So help me out if you can, if I find the answer before this happens I will share it. viva la Android!

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  • Access 2007 not allowing user to delete record in subform

    - by Todd McDermid
    Good day... The root of my issue is that there's no context menu allowing the user to delete a row from a form. The "delete" button on the ribbon is also disabled. In Access 2003, apparently this function was available, but since our recent "upgrade" to 2007 (file is still in MDB format) it's no longer there. Please keep in mind I'm not an Access dev, nor did I create this app - I inherited support for it. ;) Now for the details, and what I've tried. The form in question is a subform on a larger form. I've tried turning "AllowDeletes" on on both forms. I've checked the toolbar and ribbon properties on the forms to see if they loaded some custom stuff, but no. I've tried changing the "record locks" to "on edit", no joy. I examined the query to see if it was "too complicated" to permit a delete - as far as I can tell, it's a very simple two (linked) table join. Compared to another form in this app that does permit row deletes, it has a much more complicated (multi-join, built on queries) query. Is there a resource that would describe the required conditions for allowing deletes? Thanks in advance...

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  • Start developing a database application using Oracle + Net Beans

    - by Ranhiru
    I have thought of creating my first database application for one of my projects using Oracle and Java. I have chosen Netbeans as my development environment. I have a few questions to getting started. Please bare with me as I'm a complete beginner to Oracle + Netbeans This will be a data intensive (yet still for a college project) database application. I do not need 1000 user concurrency or any other very advanced features but basic stuff such as triggers, stored procedures etc. Will the 11g "Express" (XE) suffice for my requirements? Do i need any Java to Oracle bridge (database connectivity driver eg. ODBC etc) for Netbeans to connect to the oracle database? If yes, what are they? Does Netbeans support Oracle databases natively? Any easy to follow guide on how do i connect to the database and insert/retrieve/display data on a J2SE application? (I know that i should Google this but if there's any guide previously followed by anyone and is considered easy, it would be greatly appreciated.)

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  • XNA Vector2 Rotation Question

    - by Tom Allen
    I'm messing about with some stuff in XNA and am trying to move an object around asteroids-style in that you press left and right to rotate and up/down to go forwards and backwards in the direction you are pointing. I've got the rotation of the sprite done, but i can't get the object to move in the direction you've pointed it, it always moves up and down on the x = 0 axis. I'm guessing this is straight forward but I just can't figure it out. My "ship" class has the following properties which are note worthy here: Vector2 Position float Rotation The "ship" class has an update method is where the input is handled and so far I've got the following: public void Update(GameTime gameTime) { KeyboardState keyboard = Keyboard.GetState(); GamePadState gamePad = GamePad.GetState(PlayerIndex.One); float x = Position.X; float y = Position.Y; if (keyboard.IsKeyDown(Keys.Left)) Rotation -= 0.1f; if (keyboard.IsKeyDown(Keys.Right)) Rotation += 0.1f; if (keyboard.IsKeyDown(Keys.Up)) y -= ??; if (keyboard.IsKeyDown(Keys.Down)) y += ??; this.Position = new Vector2(x, y); } Any help would be most appreciated!

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  • routing mvc on the web

    - by generic_noob
    Hi, I was wondering if anyone could possibly provide me some advice on how i could improve the routing (and/or architecture) to each 'section' of my application. (I'm writing in PHP5, and trying to use strict MVC) Basically, I have a generic index page for the app, and that will spew out boilerplate stuff like jquery and the css etc. and it also generates the main navidation for the entire site, but i'm unsure about the best approach to connect the 'main menu' items(hyperlinks) with their associated controllers. Up until now I have been appending strings into the url and using a 'switch' statement to branch to the correct controller(and view) by extracting the strings back out of '$GET[]' to let it execute the code for the corrosponding action. for instance if i had a basic crud system for customer data, the url to edit a customers details would look like 'www.example.com/index.php?page=customer&action=edit&id=4'. I'm worried that there is a security concern by doing it this way, and i'm not sure of an alternative to branch the main 'index.php' file to the correct controller for each action once the user has clicked the link. Would it be better to use mod_rewrite to disguise the controllers names? or to create a similar system to the ASP MVC framework, where there is a seperate routing system where each url is filtered to get the associated controller? Cheers!

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  • Referencing not-yet-defined variables - Java

    - by user2537337
    Because I'm tired of solving math problems, I decided to try something more engaging with my very rusty (and even without the rust, very basic) Java skills. I landed on a super-simple people simulator, and thus far have been having a grand time working through the various steps of getting it to function. Currently, it generates an array of people-class objects and runs a for loop to cycle through a set of actions that alter the relationships between them, which I have stored in a 2d integer array. When it ends, I go look at how much they all hate each other. Fun stuff. Trouble has arisen, however, because I would like the program to clearly print what action is happening when it happens. I thought the best way to do this would be to add a string, description, to my "action" class (which stores variables for the actor, reactor, and the amount the relationship changes). This works to a degree, in that I can print a generic message ("A fight has occurred!") with no problem. However, ideally I would like it to be a little more specific ("Person A has thrown a rock at Person B's head!"). This latter goal is proving more difficult: attempting to construct an action with a description string that references actor and reactor gets me a big old error, "Cannot reference field before it is defined." Which makes perfect sense. I believe I'm not quite in programmer mode, because the only other way I can think to do this is an unwieldy switch statement that negates the need for each action to have its own nicely-packaged description. And there must be a neater way. I am not looking for examples of code, only a push in the direction of the right concept to handle this.

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  • UnicodeEncodeError: 'ascii' codec can't encode character [...]

    - by user1461135
    I have read the HOWTO on Unicode from the official docs and a full, very detailed article as well. Still I don't get it why it throws me this error. Here is what I attempt: I open an XML file that contains chars out of ASCII range (but inside allowed XML range). I do that with cfg = codecs.open(filename, encoding='utf-8, mode='r') which runs fine. Looking at the string with repr() also shows me a unicode string. Now I go ahead and read that with parseString(cfg.read().encode('utf-8'). Of course, my XML file starts with this: <?xml version="1.0" encoding="utf-8"?>. Although I suppose it is not relevant, I also defined utf-8 for my python script, but since I am not writing unicode characters directly in it, this should not apply here. Same for the following line: from __future__ import unicode_literals which also is right at the beginning. Next thing I pass the generated Object to my own class where I read tags into variables like this: xmldata.getElementsByTagName(tagName)[0].firstChild.data and assign it to a variable in my class. Now what perfectly works are those commands (obj is an instance of the class): for element in obj: print element And this command does work as well: print obj.__repr__() I defined __iter__() to just yield every variable while __repr__() uses the typical printf stuff: "%s" % self.varname Both commands print perfectly and can output the unicode character. What does not work is this: print obj And now I am stuck because this throws the dreaded UnicodeEncodeError: 'ascii' codec can't encode character u'\xfc' in position 47: So what am I missing? What am I doing wrong? I am looking for a general solution, I always want to handle strings as unicode, just to avoid any possible errors and write a compatible program. Edit: I also defined this: def __str__(self): return self.__repr__() def __unicode__(self): return self.__repr__() From documentation I got that this

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  • Semantically correct XHTML markup

    - by Dori
    Hello all. Just trying to get the hang of using the semantically correct XHTML markup. Just writing the code for a small navigation item. Where each button has effectivly a title and a descrption. I thought a definition list would therefore be great so i wrote the following <dl> <dt>Import images</dt> <dd>Read in new image names to database</dd> <dt>Exhibition Management</dt> <dd>Create / Delete an exhibition </dd> <dt>Image Management</dt> <dd>Edit name, medium and exhibition data </dd> </dl> But...I want the above to be 3 buttons, each button containing the dt and dd text. How can i do this with the correct code? Normally i would make each button a div and use that for the visual button behaviour (onHover and current page selection stuff). Any advice please Thanks

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  • Where do I attach the StoreKit delegate and observer in a Cocos2d App?

    - by Jeff B
    I have figured out how all of the StoreKit stuff works and have actually tested working code... however, I have a problem. I made my "store" layer/scene the SKProductsRequestDelegate. Is this the correct thing to do? I get the initial product info like so: SKProductsRequest *productRequest = [[SKProductsRequest alloc] initWithProductIdentifiers: productIDs]; [productRequest setDelegate: self]; [productRequest start]; The problem is that if I transition to a new scene when a request is in progress, the current layer is retained by the productRequest. This means that touches on my new scene/layer are handled by both the new layer and the old layer. I could cancel the productRequest when leaving the scene, but: I do not know if it is in progress at that point. I cannot release it because it may or may not have been released by the request delegates. There has got to be a better way to do this. I could make the delegate a class external to the current layer, but then I do not know how to easily update the layer with the product information when the handler is called.

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  • Best practice to create WPF wrapper application displaying screens on demand.

    - by Robbie
    Context: I'm developing a WPF application which will contain a lot of different "screens". Each screen contains a which on its turn contains all the visual elements. Some elements trigger events (e.g., checkboxes), a screen has individual resources, etc. The main application is "wrapper" around these screens: it contains a menubar, toolbar, statusbar and alike (in a DockPanel) and space to display one screen. Through the menubar, the user can choose which screen he wants to display. Goal: I want to dynamically load & display & (event)handle one screen in the space in the main application. I don't want to copy & paste all the "wrapper" stuff in all the different screens. And As I have many complex screens (around 300 - luckily auto-generated), I don't want to load all of them at the start of the application, but only upon request. Question: What do you recommend as the best way to realize this? What kind of things should I use and investigate: Pages or windows or User Control for the screens? Does this affect the event handling?

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  • Rails Model inheritance in forms

    - by Tiago
    I'm doing a reporting system for my app. I created a model ReportKind for example, but as I can report a lot of stuff, I wanted to make different groups of report kinds. Since they share a lot of behavior, I'm trying to use inheritance. So I have the main model: model ReportKind << ActiveRecord::Base end and created for example: model UserReportKind << ReportKind end In my table report_kinds I've the type column, and until here its all working. My problem is in the forms/controllers. When I do a ReportKind.new, my form is build with the '*report_kind*' prefix. If a get a UserReportKind, even through a ReportKind.find, the form will build the 'user_report_kind' prefix. This mess everything in the controllers, since sometimes I'll have params[:report_kind], sometimes params[:user_report_kind], and so on for every other inheritance I made. Is there anyway to force it to aways use the 'report_kind' prefix? Also I had to force the attribute 'type' in the controller, because it didn't get the value direct from the form, is there a pretty way to do this? Routing was another problem, since it was trying to build routes based in the inherited models names. I overcome that by adding the other models in routes pointing to the same controller.

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  • A question about entities, roles and interfaces in Entity Framework 4.

    - by mvole
    Hi, I am an experienced .NET developer but new to EF - so please bear with me. I will use an example of a college application to illustrate my problem. I have these user roles: Lecturer, Student, Administrator. In my code I envisage working with these entities as distinct classes so e.g. a Lecturer teaches a collection of Students. And work with 'is Student' 'TypeOf' etc. Each of these entities share lots of common properties/methods e.g. they can all log onto the system and do stuff related to their role. In EF designer I can create a base entity Person (or User...) and have Lecturer, Student and Administrator all inherit from that. The difficulty I have is that a Lecturer can be an Administrator - and in fact on occasion a Student can be a Lecturer. If I were to add other entities such as Employee and Warden then this gets even more of an issue. I could presumably work with Interfaces so a person could implement ILecturer and IStudent, however I do not see how this fits within EF. I would like to work within the EF designer if possible and I'm working model-first (coding in C#). So any help and advice/samples would be very welcome and much appreciated. Thanks

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  • What technology should I use to write my game?

    - by Alon
    I have a great idea for a 3D network game, and I've concluded that it is possible to write it in Java as an applet which will live under the web browser, just like a full software in C++. And it will look and feel the same. The main advantage of Java on C++ is that with Java you can play without downloading any software. I have already thought about the download of the graphics, sound, etc but I found a solution for it. RuneScape just proves that it is possible. So my first question is, should my game live on a web browser or on the operating system? I think that in a web browser it is much more portable, although you need install Java and stuff. But the fact is, that most MMO games are currently not in the web. If you suggest in a software so please suggest a language either - C++ or something more productive like Python or C#? So after choosing a language, I need a graphics solution. Should I write directly with OpenGL/DirectX or use a game engine? What game engine should I use? Ogre? jMonkeyEngine? What's your opinion? Thank you! P.S: Please don't use answers like "Use what you know".

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  • Auto increment with a Unit Of Work

    - by Derick
    Context I'm building a persistence layer to abstract different types of databases that I'll be needing. On the relational part I have mySQL, Oracle and PostgreSQL. Let's take the following simplified MySQL tables: CREATE TABLE Contact ( ID varchar(15), NAME varchar(30) ); CREATE TABLE Address ( ID varchar(15), CONTACT_ID varchar(15), NAME varchar(50) ); I use code to generate system specific alpha numeric unique ID's fitting 15 chars in this case. Thus, if I insert a Contact record with it's Addresses I have my generated Contact.ID and Address.CONTACT_IDs before committing. I've created a Unit of Work (amongst others) as per Martin Fowler's patterns to add transaction support. I'm using a key based Identity Map in the UoW to track the changed records in memory. It works like a charm for the scenario above, all pretty standard stuff so far. The question scenario comes in when I have a database that is not under my control and the ID fields are auto-increment (or in Oracle sequences). In this case I do not have the db generated Contact.ID beforehand, so when I create my Address I do not have a value for Address.CONTACT_ID. The transaction has not been started on the DB session since all is kept in the Identity Map in memory. Question: What is a good approach to address this? (Avoiding unnecessary db round trips) Some ideas: Retrieve the last ID: I can do a call to the database to retrieve the last Id like: SELECT Auto_increment FROM information_schema.tables WHERE table_name='Contact'; But this is MySQL specific and probably something similar can be done for the other databases. If do this then would need to do the 1st insert, get the ID and then update the children (Address.CONTACT_IDs) – all in the current transaction context.

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  • C# Virtual method call in constructor - how to refactor?

    - by Cristi Diaconescu
    I have an abstract class for database-agnostic cursor actions. Derived from that, there are classes that implement the abstract methods for handling database-specific stuff. The problem is, the base class ctor needs to call an abstract method - when the ctor is called, it needs to initialize the database-specific cursor. I know why this shouldn't be done, I don't need that explanation! This is my first implementation, that obviously doesn't work - it's the textbook "wrong way" of doing it. The overridden method accesses a field from the derived class, which is not yet instantiated: public abstract class CursorReader { private readonly int m_rowCount; protected CursorReader() { m_rowCount = CreateCursor(sqlCmd); //virtual call ! } protected abstract int CreateCursor(string sqlCmd); } public class SqlCursorReader : CursorReader { private SqlConnection m_sqlConnection; public SqlCursorReader(string sqlCmd, SqlConnection sqlConnection) { m_sqlConnection = sqlConnection; //field initialized here } protected override int CreateCursor(string sqlCmd) { //uses not-yet-initialized member *m_sqlConnection* //so this throws a NullReferenceException var cursor = new CustomCursor(sqlCmd, m_sqlConnection); return cursor.Count(); } } I will follow up with an answer on my attempts to fix this...

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  • Reporting Services: Tablix RepeatColumnHeaders doesn't work on some reports

    - by I Have the Hat
    So I've got various reports that consist of a DataSet rendered in a Tablix... pretty garden variety stuff. There is a property for the Tablix control named RepeatColumnHeaders, which I have set to True for each report in question. The explanation for this property states “Indicates whether column headers are repeated on each page on which part of the data region appear.” Sounds pretty straightforward, but on some reports it works and on others it does not. I can't seem to find what's different about the reports that might affect this. On one report where the headers do repeat, there is some fairly arcane grouping mojo, but in an example where it doesn't work the Tablix only has one level--no grouping. I would expect the multi-nested one to be the problem, not the flat one. Maybe it's a different problem altogether. I threw together a simple Tablix rendering SELECT * FROM Foo, accepted all the default values, which results in RepeatColumnHeaders being set to False, and lo and behold the column headers do repeat for that report... Grrr. Any insights greatly appreciated.

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  • C++ Declarative Parsing Serialization

    - by Martin York
    Looking at Java and C# they manage to do some wicked processing based on special languaged based anotation (forgive me if that is the incorrect name). In C++ we have two problems with this: 1) There is no way to annotate a class with type information that is accessable at runtime. 2) Parsing the source to generate stuff is way to complex. But I was thinking that this could be done with some template meta-programming to achieve the same basic affect as anotations (still just thinking about it). Like char_traits that are specialised for the different types an xml_traits template could be used in a declaritive way. This traits class could be used to define how a class is serialised/deserialized by specializing the traits for the class you are trying to serialize. Example Thoughs: template<typename T> struct XML_traits { typedef XML_Empty Children; }; template<> struct XML_traits<Car> { typedef boost::mpl::vector<Body,Wheels,Engine> Children; }; template<typename T> std::ostream& Serialize(T const&) { // my template foo is not that strong. // but somthing like this. boost::mpl::for_each<typename XML_Traits<T>::Children,Serialize>(data); } template<> std::ostream& Serialize<XML_Empty>(T const&) { /* Do Nothing */ } My question is: Has anybody seen any projects/decumentation (not just XML) out there that uses techniques like this (template meta-programming) to emulate the concept of annotation used in languges like Java and C# that can then be used in code generation (to effectively automate the task by using a declaritive style). At this point in my research I am looking for more reading material and examples.

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