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• EntityFramework how to Override properties

  - by plotnick

  I've just started using EF in VS2010. That thing is just amazin'. I frankly can't understand something. For example I have EntityType with property, they generated from database structure. Now, I have to simply override that property in my code. I don't need to save value of the property back into DB, but everytime when it gets read from DB it should be substituted with run-time calculated value. Of course I can create derived class based on my EntityType but I've tried and found kinda difficulties, I'm not sure this is kinda right way to do. Anyway even when I try to change the whole EntityType to Abstract, damn Visual Studio doesn't want to validate that and says something like: "Error 2078: The EntityType 'AssetsModel.Asset' is Abstract and can be mapped only using IsTypeOf." "Error 2063: At least one property must be mapped in the set mapping for 'Assets'" What the hell is this suppose to mean I dunno.. Any ideas gentlemen?

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• How to organise a many to many relationship in MongoDB

  - by Gareth Elms

  I have two tables/collections; Users and Groups. A user can be a member of any number of groups and a user can also be an owner of any number of groups. In a relational database I'd probably have a third table called UserGroups with a UserID column, a GroupID column and an IsOwner column. I'm using MongoDB and I'm sure there is a different approach for this kind of relationship in a document database. Should I embed the list of groups and groups-as-owner inside the Users table as two arrays of ObjectIDs? Should I also store the list of members and owners in the Groups table as two arrays, effectively mirroring the relationship causing a duplication of relationship information? Or is a bridging UserGroups table a legitimate concept in document databases for many to many relationships? Thanks

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• How to use TestAndSet() for solving the critical section problem?

  - by Dan Mantyla

  I'm studying for an exam and I'm having difficulty with a concept. This is the pseudo code I am given: int mutex = 0; do { while (TestAndSet(&mutex)); // critical section mutiex = 0; // remainder section } while (TRUE); My instructor says that only two of the three necessary conditions (mutual exclusion, progress, and bounded waiting) are met with this code, but I don't understand which one isn't being met...?? How should the code be modified to support the missing condition to solve the critical region problem? Thanks in advance for any insight!

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• possible to show composition relationship in a diagram generated from PHP source code?

  - by ajsie

  i have tested several UML applications for whether they could show composition relationships in the UML diagrams generated form the PHP source code or not, and the result is they can't. i know that this is a typical problem for PHP cause we don't declare a data type when we code, so it's difficult for the UML applications to know if an instance variable is a reference to an object or not. i also tested nWire with the same result. will there never be applications that could show us a complete map over all object relationships more than just inheritance? i think it's a pity that you can't have a good view over all the relationships for an application. cause when i use an open source solution, i always want to know how the objects are related to each other. maybe we could make comments for the instance variable telling the software that this is an reference to an object? but that would mean that the mapping software is using this solution. i feel its a pity nWire/visual paradigm can't give us a complete map:(

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• How to dynamically order many-to-many relationship with JPA or HQl?

  - by Indrek

  I have a mapping like this: @ManyToMany(cascade = CascadeType.PERSIST) @JoinTable( name="product_product_catalog", joinColumns={@JoinColumn(name="product_catalog", referencedColumnName="product_catalog")}, inverseJoinColumns={@JoinColumn(name="product", referencedColumnName="product")}) public List<Product> products = new ArrayList<Product>(); I can fetch the products for the catalog nicely, but I can't (dynamically) order the products. How could I order them? I probably have to write a many-to-many HQL query with the order-by clause? I though of passing the orderBy field name string to the query, or is there a better solution? Tables are: products, product_catalog, product_product_catalog (associative table) P.S. Using Play! Framework JPASupport for my entities.

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• Is this the correct why of speaking to a "Content Manager" Class?

  - by DeanMc

  I am creating a silverlight site. I am currently breaking out my ideas into pieces of functionality. One of the idea's I have is the concept of a content manager. This is essentially a UI control with 4 regions. Top, Bottom, Right & Left. I also have a collection of objects that are considered "Menu Items". These are controls that function as a way to navigate around, similar to links. The idea I have is to implement an IMenuItem interface. Among the standard pieces of information (Text, PageReference, etc) I was also going to hold a reference to the content manager. My idea behind this thinking is that I can pass the PageReference to a property on the ContentManager and then call a method which knows how to update the content manager accordingly. Is this the best way of implementing this or is their some sort of pattern for it?

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• How to link to a folder in document library from sharepoint list item?

  - by kyrisu

  Hi, Background: I have an items on the sharepoint list. I also have a corresponding folder in a document library that contains documents about this item. I want to be able to get to this folder straight from the item properties. I have tried to create a lookup column containing folder ID, but that doesn't help cause folder is not a type and it just doesn't work. Other solution would be to create link column but if I will create it staticly - after creating alternative mapping (and getting to the page from the internet for example) it won't work. (so solution posted here won't work for me). I want to create this link from sharepoint workflow. I have a custom action that can return any info about the folder I want (ID, URL etc). Question: How to link from sharepoint list item to a folder in document library?

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• Learning C++ from AS3

  - by grey

  I'm a decent AS3 programmer. I work in games, and that is my reason for programming. While there is much I can accomplish with Adobe AIR, my understanding at this point is that learning C++ is probably a good direction to take. I would learn a lot of valuable lower level programming if I needed it down the road, and I would have an easier time learning other C oriented languages. I see a lot of information for people looking to learn AS3 who know C++, but not the other way around. Why C++? Cross platform compatibility is important to me, so I'm not particularly interested in C# or Objective-C at this junction. I'm also aware of HaXe, and while I love the concept, after doing some research I'm worried about investing a lot of time into something so recent with limited learning resources and documentation. I'm looking for advice and resources (books, articles) related to this topic. Thanks in advance!

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• Select one column from a row in hibernate

  - by ComfortablyNumb

  I am trying to do a simple query to get a unique result back in hibernate here is my code. public String getName(Integer id) { Session session = getSessionFactory().openSession(); String name = (String)session.createSQLQuery("SELECT name FROM users WHERE user_id = :userId").setParameter("userId", id).uniqueResult(); return name; } The name that is being returned is stored as HTML text that includes html syntacx language. I think this is what is causing the problem but it doesnt make sense I just want to return it as a string. It is only happening on this one field name, I can get every other field in the row but this one it gives me the error. I am getting an exception. The exception I am getting is No Dialect mapping for JDBC type: -1; nested exception is org.hibernate.HibernateException How do you query for a specific column on a row in hibernate?

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• is there some lightweight tecnique for adding type safety to identifier properties?

  - by shoren

  After using C++ I got used to the concept of Identifier which can be used with a class for the type, provides type safety and has no runtime overhead (the actual size is the size of the primitive). I want to do something like that, so I will not make mistakes like: personDao.find(book.getId());//I want compilation to fail personDao.find(book.getOwnerId());//I want compilation to succeed Possible solutuions that I don't like: For every entity have an entity id class wrapping the id primitive. I don't like the code bloat. Create a generic Identifier class. Code like this will not compile: void foo(Identifier book); void foo(Identifier person); Does anyone know of a better way? Is there a library with a utility such as this? Is implementing this an overkill? And the best of all, can this be done in Java without the object overhead like in C++?

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• What's the deal with all of the abstract stuff?

  - by JustVenting

  I see a lot of talk about MVVM, MVC, Design Patterns etc... You know, some guy has a blog, and he spent the last six months learning about one these things and desiging a program centered around that concept and then he goes on and on about it like its better than sliced bread. I read all of this crap and I wonder, whatever happened to simple logical programming? Not self-absorbed huge frameworks of design patterns and mvc and whatever else you can think of... just simple linear programming, perhaps a few classes to encapsulate things here and there.

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• PHP OOP: Unique method per argument type?

  - by sunwukung

  I'm writing a little homebrew ORM (academic interest). I'm trying to adhere to the TDD concept as a training exercise, and as part of that exercise I'm writing documentation for the API as I develop the class. Case in point - I'm working on a classic "getCollection" type mapper class. I want it to be able to retrieve collections of asset X (let's say blog posts) for a specific user, and also collections based on an arbitrary array of numeric values. So - you might have a method like any one of these $User = $UserMapper->load(1); $ArticleCollection = $ArticleMapper->getCollection(range(10,20)); $ArticleCollection = $ArticleMapper->getCollection($User); $ArticleCollection = $ArticleMapper->getCollection($User->getId()); So, in writing the documentation for the getCollection method - I want to declare the @param variable in the Docblock. Is it better to have a unique method for each argument type, or is it acceptable to have a method that delegates to the correct internal method/class based on argument type?

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• using helper methods in a view in rails 3

  - by Frida777

  Hello everyone, there is something that is disturbing me a bit about rails 3. i am trying to upgrade my application from rails 2 to rails 3. i followed all the steps necessary to do and things were working well for me till now except one thing: i have a helper method that is defined differently in different helpers, for example it is defined in the application_helper in one way and the same method defined in a different way in the homepage_helper, and defined differently in another helper, let's say video_helper, in addition to that, it is used in a shared view that is used throughout the application, now if i am in the homepage, i want this function to get called from the homepage_helper and if i am in the video page, the function must be called from the video_helper, based on the concept of convention in rails, this worked perfectly in rails 2 but in rails 3, the function is always called from the last helper, alphabetically ordered, that is in the example, video_helper. How can i fix this? Kindly advice. Appreciate all the help.

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• Is it a good idea to apply some basic macros to simplify code in a large project?

  - by DoctorT

  I've been working on a foundational c++ library for some time now, and there are a variety of ideas I've had that could really simplify the code writing and managing process. One of these is the concept of introducing some macros to help simplify statements that appear very often, but are a bit more complicated than should be necessary. For example, I've come up with this basic macro to simplify the most common type of for loop: #define loop(v,n) for(unsigned long v=0; v<n; ++v) This would enable you to replace those clunky for loops you see so much of: for (int i = 0, i < max_things; i++) With something much easier to write, and even slightly more efficient: loop (i, max_things) Is it a good idea to use conventions like this? Are there any problems you might run into with different types of compilers? Would it just be too confusing for someone unfamiliar with the macro(s)?

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• How to Delete Duplicate Rows in SQL 2000?

  - by Mikecancook

  I thought I had this figured out but it turns out I'm just deleting the first record. The following returns the duplicate rows. All have a count of 2. I just want to delete the first one for each duplicate record. select scorestudentid, scoreadvisor, scorecorrect, count(*) from scores where scoretestid = 3284 group by scorestudentid, scoreadvisor, scorecorrect having count(scorestudentid) > 1 Which returns: scorestudentid scoreadvisor scorecorrect no column name 13033719 28059 3.0 2 13033777 28086 3.0 2 13033826 28147 3.0 2 13033960 28023 3.0 2 So I put this together thinking it would work: set rowcount 1 delete from scores where scoretestid = 3284 and scorestudentid in ( select scorestudentid from scores where scoretestid = 3284 group by scorestudentid having count(scorestudentid) > 1) It really seems like it should be a simple concept but I'm not getting it.

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• How can I make an aggregated property support ActiveRecord::Dirty semantics?

  - by Eric

  I have an aggregated attribute which I want to be able ask about its _changed? ness, etc. composed_of :range, :class_name => 'Range', :mapping => [ %w(range_begin begin), %w(range_end end)], :allow_nil => true If I use the aggregation: foo.range = 1..10 This is what I get: foo.range # => 1..10 foo.range_changed? # NoMethodError foo.range_was # ditto foo.changed # ['range_begin', 'range_end'] So basically, I'm not getting ActiveRecord::Dirty semanitcs on aggregated attributes. Is there any way to do that? I'm not having a lot of luck with alias_attribute_with_dirty, etc.

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• basic database design table on rails

  - by runcode

  I am confuse on a concept. I am doing this on rails. Is that Entity set equal to a table in the database? Is that Relationship set equal to a table in the database? Let say we have Entity set "USER" and Entity set "POST" and Entity set "COMMENT" User- can post many posts and comments as they want Post- belong to users Comments-belong to posts ,users, so comment is weak entity. SCHEMA ====== USER -id -name POST -id -user_id(FK) -comment_id (FK) COMMENT -id -user_id (FK) -post_id (FK) so USER,POST,COMMENT are tables I think. And what else is a table? And do I need a table for the relationship??

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• IIS7 and ARR as reverse proxy for Subversion

  - by Paul Stovell

  I am using IIS7 and the Application Request Routing extension to act as a reverse proxy to Subversion running on Apache. The proxy works fine and I am able to explore the server, and even perform a "check out". However, I cannot browse to files that would normally be forbidden by ASP.NET - for example, .cs, .csproj, and so on. Files ASP.NET wouldn't be concerned with - such as .txt - are fine. I tried to edit the global web.config to remove the Forbidden handler mapping for these files, but it did not seem to make a difference. Is there any way to allow the URL rewriting module in IIS7 to work, while allowing all file extensions to be rendered?

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• Reading Matrices in MATLAB and assigning coordinates to the entries

  - by Michael Schofield

  Hi, I'm a bit new to MATLAB. Basically, I have a 25x25 Matrix, complete with various random entries ranging from 0 to 3. I need to write a program that reads this matrix, and assigns x-y coordinates to the entries, so that when I ask for an input of a particular x-y coordinate which has, say an entry of 3, then it will result in an error. I'm a bit overwhelmed - but I understand the general concept of what I'm supposed to be finding. I'm wondering if I should use a plot instead to help me.

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• Routing fails when only category is supplied

  - by creativeincode

  My website uses categories and sub-categories. I'd like the follow mapping: /Category/Fruit /Category/Fruit/Apples But if I use the below: routes.MapRoute( "Category", // Route name "Category/{category}/{subcategory}", // URL with parameters new { controller = "Entity", action = "Category" } // Parameter defaults ); I get a 404 for /Category/Fruit however /Category/Fruit/Apples works ok. I'd like /Category/Fruit to work as well but I can't add another route with the same name. How do I get around this? Thanks in advance.

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• Oracle global_names DELETE problem

  - by jyzuz

  I'm using a database link to execute a DELETE statement on another DB, but the DB link name doesn't conform to global naming, and this requirement cannot change. Also I have global_names set to false, and cannot be changed either. When I try to use these links however, I receive: ORA-02069: - global_names parameter must be set to TRUE for this operation Cause: A remote mapping of the statement is required but cannot be achieved because GLOBAL_NAMES should be set to TRUE for it to be achieved. - Action: Issue `ALTER SESSION SET GLOBAL_NAMES = TRUE` (if possible) What is the alternative action when setting global_names=true is not possible? Cheers, Jean

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• Inconsistent Routing Results in MVC

  - by HapiDjus

  Seems I'm still missing something to the MVC routing concept. I have a route that follows nearly the same pattern as another route in an area but for what ever reason I get a 404 every time I attempt to run it. I've tried to use Phil Haack's Route Tester DLL and according to that it hits the correct route (matched route comes out to common/itemhistory/{contentid}). When I try to run it for real, it blows up. I'm trying to map a call to a JsonResult by passing a Guid. I've had success with other routes working fine (common is an area in my site). What could I be doing wrong? context.MapRoute( "ItemHistory", "common/itemhistory/{contentid}", new { controller = "common", action = "GetItemHistory" }, new { contentid = @"^(\{){0,1}[0-9a-fA-F]{8}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{12}(\}){0,1}$" } ); context.MapRoute( "Common_default", "common/{action}", new { controller="common", action = "Index" } );

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• Help in formulating sql query

  - by AJ

  Here is my scenario Table 1: GID || Info1 Table 2: GID || Tb1GID (refers to GID of Table1) || Info2 Table 3: GID || Info3 Table 4: GID || Tb2GID (refers to GID of Table2 || Tb3GID (refers to Table3 GID || Value Now I have to build an sql query to get the value, given a particular Info1, Info2, Info3. Essentially, I have to get the GID, of table 1 using info1, GID of table to , by mapping info2 and GID of table 1. And then get the GID of table 3 using info 3. And combine these to GIDs to get the value in table 4. What is the most optimal way of constructing an sql query for this one?

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• Use count or have a field that tallies?

  - by Dan LaManna

  Fairly simple concept, making an extremely basic message board system and I want users to have a post count. Now I was debating on whether or not to have a tally in their row that is added each time a post by them is created, or subtracted by one each time a post of theirs is deleted. However I'm sure that performing a count query when the post count is requested would be more accurate due to unforseen circumstances (say a thread gets deleted and it doesn't lower their tally properly), however this seems like it would be less efficient to run a query EVERY time their post count is loaded, especially in the case of them having 10 posts on the same page and it lists their post count each post. Thoughts/Advice? Thanks

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• How to start coding the "Dining Philosophers" simulation?

  - by GrizzlyGuru

  I'm not a beginner at C# but I really need to increase my understanding, so I've picked a classic deadlock problem to code to help teach myself some of the more advanced concepts of C#. The Dining Philosophers Problem seems like a good one, but I need a little help to get started. I know I need to approach the "diners" as objects, but to simulate the random delays between eating, should I look to threading with each diner in a separate thread? Do I need some kind of "master" to monitor all the actions? Any general design concept advice is welcome, but I'd like to do the grunt programming as an exercise. Thanks!

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