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  • Classes to Entities; Like-class inheritence problems

    - by Stacey
    Beyond work, some friends and I are trying to build a game of sorts; The way we structure some of it works pretty well for a normal object oriented approach, but as most developers will attest this does not always translate itself well into a database persistent approach. This is not the absolute layout of what we have, it is just a sample model given for sake of representation. The whole project is being done in C# 4.0, and we have every intention of using Entity Framework 4.0 (unless Fluent nHibernate can really offer us something we outright cannot do in EF). One of the problems we keep running across is inheriting things in database models. Using the Entity Framework designer, I can draw the same code I have below; but I'm sure it is pretty obvious that it doesn't work like it is expected to. To clarify a little bit; 'Items' have bonuses, which can be of anything. Therefore, every part of the game must derive from something similar so that no matter what is 'changed' it is all at a basic enough level to be hooked into. Sounds fairly simple and straightforward, right? So then, we inherit everything that pertains to the game from 'Unit'. Weights, Measures, Random (think like dice, maybe?), and there will be other such entities. Some of them are similar, but in code they will each react differently. We're having a really big problem with abstracting this kind of thing into a database model. Without 'Enum' support, it is proving difficult to translate into multiple tables that still share a common listing. One solution we've depicted is to use a 'key ring' type approach, where everything that attaches to a character is stored on a 'Ring' with a 'Key', where each Key has a Value that represents a type. This works functionally but we've discovered it becomes very sluggish and performs poorly. We also dislike this approach because it begins to feel as if everything is 'dumped' into one class; which makes management and logical structure difficult to adhere to. I was hoping someone else might have some ideas on what I could do with this problem. It's really driving me up the wall; To summarize; the goal is to build a type (Unit) that can be used as a base type (Table per Type) for generic reference across a relatively global scope, without having to dump everything into a single collection. I can use an Interface to determine actual behavior so that isn't too big of an issue. This is 'roughly' the same idea expressed in the Entity Framework.

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  • how to specify a BIGINT in a ruby scaffold?

    - by webdestroya
    I am trying to create a model in ruby that uses a BIGINT datatype (as opposed to the INT done by :integer). I have search all over Google, but all I seem to find is "run an SQL statement to alter the table to a BIGINT" - This seems a bit hack-ish to me, so I wanted to know if there was a way to specify a bigint in the ruby system like :big_int or something Any ideas?

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  • how i can use SAX parser

    - by moustafa
    This is what the result should look like when i parse it through a SAX parser http://img13.imageshack.us/img13/6950/75914446.jpg This is the XML source code from which i need to generate the display: <orders> <order> <count>37</count> <price>49.99</price> <book> <isbn>0130897930</isbn> <title>Core Web Programming Second Edition</title> <authors> <count>2</count> <author>Marty Hall</author> <author>Larry Brown</author> </authors> </book> </order> <order> <count>1</count> <price>9.95</price> <yacht> <manufacturer>Luxury Yachts, Inc.</manufacturer> <model>M-1</model> <standardFeatures oars="plastic" lifeVests="none">false</standardFeatures> </yacht> </order> <order> <count>3</count> <price>22.22</price> <book> <isbn>B000059Z4H</isbn> <title>Harry Potter and the Order of the Phoenix</title> <authors> <count>1</count> <author>J.K. Rowling</author> </authors> </book> </order> i really have no clue how to code the functions but i have just set up the parser $xmlParser = xml_parser_create("UTF-8"); xml_parser_set_option($xmlParser, XML_OPTION_CASE_FOLDING, false); xml_set_element_handler($xmlParser, 'startElement', 'endElement'); xml_set_character_data_handler($xmlParser, 'HandleCharacterData'); $fileName = 'orders.xml'; if (!($fp = fopen($fileName, 'r'))){ die('Cannot open the XML file: ' . $fileName); } while ($data = fread($fp, 4096)){ $parsedOkay = xml_parse($xmlParser, $data, feof($fp)); if (!$parsedOkay){ print ("There was an error or the parser was finished."); break; } } xml_parser_free($xmlParser); function startElement($xmlParser, $name, $attribs) { } function endElement($parser, $name) { } function HandleCharacterData($parser, $data) { }

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  • Where are the menu,header,footer loaded in an MVC structures

    - by Saif Bechan
    I am creating an framework in PHP, and i am using and MVC structure. My link look something like this: mydomain.com/controller/action So this link loads a controller, which loads the needed action. Now my page needs a header, footer, and it has a menu which is in the database. Where do i load all these things. Is this the job of the controller, or the job of the model.

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  • Combobox item style

    - by user373721
    my project is asp.net MVC, using Telerik MVC combobox. I can change the sytle of the first item if I use: var item = combobox.dropDown.$items.first(); item.addClass('test'); Or change all items, using: combobox.dropDown.$items.addClass('test'); But I need to change just specific items (based on a model), I tried: combobox.dropDown.$items[1].addClass('test'); I get this error: Object doesn't support property or method 'addClass'

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  • Embedding a scripting engine in C++

    - by Jen
    I'm researching how to best extend a C++ application with scripting capability, and I am looking at either Python or JavaScript. User-defined scripts will need the ability to access the application's data model. Have any of you had experiences with embedding these scripting engines? What are some potential pitfalls?

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  • Sparse (Pseudo) Infinite Grid Data Structure for Web Game

    - by Ming
    I'm considering trying to make a game that takes place on an essentially infinite grid. The grid is very sparse. Certain small regions of relatively high density. Relatively few isolated nonempty cells. The amount of the grid in use is too large to implement naively but probably smallish by "big data" standards (I'm not trying to map the Internet or anything like that) This needs to be easy to persist. Here are the operations I may want to perform (reasonably efficiently) on this grid: Ask for some small rectangular region of cells and all their contents (a player's current neighborhood) Set individual cells or blit small regions (the player is making a move) Ask for the rough shape or outline/silhouette of some larger rectangular regions (a world map or region preview) Find some regions with approximately a given density (player spawning location) Approximate shortest path through gaps of at most some small constant empty spaces per hop (it's OK to be a bad approximation often, but not OK to keep heading the wrong direction searching) Approximate convex hull for a region Here's the catch: I want to do this in a web app. That is, I would prefer to use existing data storage (perhaps in the form of a relational database) and relatively little external dependency (preferably avoiding the need for a persistent process). Guys, what advice can you give me on actually implementing this? How would you do this if the web-app restrictions weren't in place? How would you modify that if they were? Thanks a lot, everyone!

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  • Is MapReduce one form of Continuation-Passing Style (CPS)?

    - by Jeffrey
    As the title says. I was reading Yet Another Language Geek: Continuation-Passing Style and I was sort of wondering if MapReduce can be categorized as one form of Continuation-Passing Style aka CPS. I am also wondering how can CPS utilise more than one computer to perform complex computation. Maybe CPS makes it easier to work with Actor model.

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  • MVVM Group Radio Button

    - by LnDCobra
    What is the best way of binding a number of RadioButtons to an enum using MVVM? The only way I can think of is binding each group box's IsChecked to a property, and in the setter of that property assign a value to an enum in the view model. Any help is appreciated.

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  • Python modify an xml file

    - by michele
    I have this xml model. link text So I have to add some node (see the text commented) to this file. How I can do it? I have writed this partial code but it doesn't work: xmldoc=minidom.parse(directory) child = xmldoc.createElement("map") for node in xmldoc.getElementsByTagName("Environment"): node.appendChild(child) Thanks in advance.

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  • django: Changing auto_id of ModelForm based form class

    - by Meilo
    Every time I create an instance of the TestForm specified below, I have to overwrite the standard id format with auto_id=True. How can this be done once only in the form class instead? Any hints are very welcome. views.py from django.forms import ModelForm from models import Test class TestForm(ModelForm): class Meta: model = Test def test(request): form = TestForm(auto_id=True)

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  • Entity Framework foreign relationship issue

    - by Doug Hope
    I've had an entity framework model working for some time. Yesterday, it suddenly started complaining about a foreign key relationship issue during an insert. I've checked the fields and can do a manual insert using the exact field values. But the EF continues to complain. Any ideas what could have happened?

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  • HFT strategy coding on hardware

    - by bsobaid
    Hardware accelaration and embedded programming has mostly been used so far to parse datafeed and/or to route orders to exchange. Have there been attempts to write simpler HFT strategies such as equity market-making in hardware? Have they been successful? Which companies are doing this and what kind of programming model is used?

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  • Is it possible ot mix named pipe with select in perl

    - by Haiyuan Zhang
    I need to write a daemon that supposed to have one TCP socket and one named pipe. Usually if I need to implement a multi IO server with "pure" sockets, the select based multi-IO model is always the one I will choose. so does anyone of you have ever used named pipe in select or you can just tell me it is impossible. thanks in advance.

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  • How to write a spinlock without using CAS

    - by Martin
    Following on from a discussion which got going in the comments of this question. How would one go about writing a Spinlock without CAS operations? As the other question states: The memory ordering model is such that writes will be atomic (if two concurrent threads write a memory location at the same time, the result will be one or the other). The platform will not support atomic compare-and-set operations.

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  • Creating a table with an initial element selected

    - by Tony
    I want to create a table which displays in each row a set of data, in addition to a radio button for possible selection. This can be achieved easily by using a simple table model class which extends the DefaultTableModel and a cell renderer and editor class which implements the TableCellRenderer and TableCellEditor interfaces respectively. What I really couldn't manage to do is to make the table to display initially one of the elements (rows) initially selected. It seems straightforward but it isn't...does anybody have a clue about it?

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  • Linq to SQL code generator features

    - by Anders Abel
    I'm very fond of Linq to SQL and the programming model it encourages. I think that in many cases when you are in control of both the database schema and the code it is not worth the effort to have different relational and object models for the data. Working with Linq to SQL makes it simple to have type safe data access from .NET, using the partial extension methods to implement business rules. Unfortunately I do not like the dbml designer due to the lack of a schema refresh function. So far I have used SqlMetal, but that lacks the customization options of the dbml designer. Because of that I've started working on a tool which regenerates the whole code file like SqlMetal, but has the ability to do the customizations that are available in the dbml designer (and maybe more in the future). The customizations will be described in an xml file which only contains those parts that shouldn't have default values. This should keep the xml file size down as well as the maintenance burden of it. To help me focus on the right features, I would like to know: What would be your favourite feature in a linq to sql code generator?

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  • Best editor for CodeIgniter?

    - by Rismo
    I'm learning CodeIgniter and I come from Microsoft Visual Studio so I'm used to the auto complete feature. I've been using notepad++ so far but I wonder if anyone knows an editor that works better with CodeIgniter. I would love to see features like: Right-click - Add new model Right-click - Add new view Autocomplete with CodeIgniter helpers and libraries

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  • ISBNs are used as primary key, now I want to add non-book things to the DB - should I migrate to EAN

    - by fish2000
    I built an inventory database where ISBN numbers are the primary keys for the items. This worked great for a while as the items were books. Now I want to add non-books. some of the non-books have EANs or ISSNs, some do not. It's in PostgreSQL with django apps for the frontend and JSON api, plus a few supporting python command-line tools for management. the items in question are mostly books and artist prints, some of which are self-published. What is nice about using ISBNs as primary keys is that in on top of relational integrity, you get lots of handy utilities for validating ISBNs, automatically looking up missing or additional information on the book items, etcetera, many of which I've taken advantage. some such tools are off-the-shelf (PyISBN, PyAWS etc) and some are hand-rolled -- I tried to keep all of these parts nice and decoupled, but you know how things can get. I couldn't find anything online about 'private ISBNs' or 'self-assigned ISBNs' but that's the sort of thing I was interested in doing. I doubt that's what I'll settle on, since there is already an apparent run on ISBN numbers. should I retool everything for EAN numbers, or migrate off ISBNs as primary keys in general? if anyone has any experience with working with these systems, I'd love to hear about it, your advice is most welcome.

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  • MongoDB ruby dates

    - by MB
    I have a collection with an index on :created_at (which in this particular case should be a date) From rails what is the proper way to save an entry and then retrieve it by the date? I'm trying something like: Model: field :created_at, :type = Time script: Col.create(:created_at = Time.parse(another_model.created_at).to_s and Col.find(:all, :conditions = { :created_at = Time.parse(same thing) }) and it's not returning anything

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  • Which system modelling notation for showing interconnections and internal logical structures?

    - by user1043838
    I am trying to model a collection of systems, their various interconnections, as well as their internal logical structures, as a message is passed through them, initiated by an actor. I have been using BPMN 2.0 notation with Yaoqiang Editor. However I'm not sure if I'm doing this right, or even using the right notation. System example Is this correct, if not, can you recommend an alternate notation or method of displaying the systems? Thanks for all suggestions

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  • Transformation of records 1 column 3 row -> 1 row 3 column

    - by Nehal Rupani
    First look at below query SELECT count(id) as total_record, id, modeller, MONTHNAME(completed_date) as current_month, Quarter(completed_date) as current_quarter, Difficulty, YEAR(completed_date) as current_year FROM model WHERE modeller != '' AND completed_date BETWEEN '2010-04-01' AND '2010-05-31' AND Difficulty != '' Group by Difficulty, Month(completed_date) Order by Month(completed_date) ASC Results I am getting is Modeller Month Year Difficulty ------------------------------------- XYZ Jan 2010 23 XYZ Jan 2010 14 XYZ Jan 2010 15 ABC Feb 2010 5 ABC Feb 2010 14 ABC Feb 2010 6 I want result like Modeller Month Year Difficulty -------------------------------------- XYZ Jan 2010 23, 14, 15 ABC Feb 2010 5, 14, 6 My database is Mysql for application i am developing so any help would be greatly appericated.

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  • In-app subscription apps

    - by Ron Srebro
    Does anyone know of an app that implemented an in-app subscription? I thought about how the subscription model can be implemented and always ends up with more problems to every possible solution I can think of, so I'm wondering if anyone knows of an app that actually does that. Thanks

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  • Html.DropDownList - Disabled/Readonly

    - by ETFairfax
    Hi, What option do I need to set to make a drop down box readonly when using MVCs Html.DropDownList? I've tried things like.... Html.DropDownList("Types", Model.Types, new { _Enabled = "false" }) ...and many different things along this line; alas no joy! I thought this would be an easy.....and it probably is!!!!! Thanks, ETFairfax.

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