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Search found 6149 results on 246 pages for 'concept mapping'.

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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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• 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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• 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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• Capturing system command output as a string

  - by dreeves

  Perl and PHP do this with backticks. For example: $output = `ls`; This code returns a directory listing into the variable $output. A similar function, system("ls"), returns the operating system return code for the given command. I'm talking about a variant that returns whatever the command prints to stdout. (There are better ways to get the list of files in a directory; the example code is an example of this concept.) How do other languages do this? Is there a canonical name for this function? (I'm going with "backtick"; though maybe I could coin "syslurp".)

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• Splitting string to integer from single-line user input?

  - by pootzko

  I just started learning some ruby, and I want to do something like this: print "Insert two numbers: " a, b = gets.split(" ") but I want to make a and b to be integers at the same time (in the same line).. If I add .to_i to the second line (before or after split(" ")), it doesn't work... so, how should I approach this? mapping, splitting, slicing? ok, I know I could use scanf, but other than scanf, how would I do this? sorry for such a noobish question, but I just couldn't find a good enough answer only googling...

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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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• How to access the backing field of a base class using fluent nhibernate?

  - by Akk

  How do i set the Access Strategy in the mapping class to point to the base _photos field? public class Content { private IList<Photo> _photos; public Content() { _photos = new List<Photo>(); } public virtual IEnumerable<Photo> Photos { get { return _photos; } } public virtual void AddPhoto() {...} } public class Article : Content { public string Body {get; set;} } I am currently using the following to try and locate the backing field but an exception is thrown as it cannot be found. public class ArticleMap : ClassMap<Article> { HasManyToMany(x => x.Photos) .Access.CamelCaseField(Prefix.Underscore) //_photos //... } i tried moving the backing field _photos directly into the class and the access works. So how can i access the backing field of the base class?

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• What's a good, threadsafe, way to pass error strings back from a C shared library

  - by PerilousApricot

  Hello, all- I'm writing a C shared library for internal use (I'll be dlopen()'ing it to a c++ application, if that matters). The shared library loads (amongst other things) some java code through a JNI module, which means all manners of nightmare error modes can come out of the JVM that I need to handle intelligently in the application. Additionally, this library needs to be re-entrant. Is there in idiom for passing error strings back in this case, or am I stuck mapping errors to integers and using printfs to debug things? Thanks!

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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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• 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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• 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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• geom_rect and NULL

  - by csgillespie

  I've been looking at the geom_rect example in section 5.10 of the ggplot2 book and don't understand the purpose of the NULL's in the aes function. For example, using the mpg data: g = ggplot(data=mpg, aes(x=displ, y=hwy)) + geom_point() #Produces a plot with a transparent filled region g + geom_rect(aes(NULL, NULL), alpha=0.1,xmin=5, xmax=7, ymin=10, ymax=45, fill="blue") #Solid filled region (v0.9) or nothing in v0.8 g + geom_rect(alpha=0.1,xmin=5, xmax=7, ymin=10, ymax=45, fill="blue") My understanding is that the NULL's are resetting the x & y mapping, but I don't see why this should affect the transparency.

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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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• Disable Foreign Key Exposure in Entity Framework?

  - by davemackey

  When I originally created a Dynamic Data project I told it to expose the foreign keys, but now I can't make mappings between two entities b/c of the foreign keys. When I click on mapping details while focused on my association I receive the message: Mappings are not allow for an association over exposed foreign keys. So I'd like to disable the exposure of the foreign keys but am unsure how to do this without creating a new Entity Model from scratch. I'm not far along - so that wouldn't be hard, but I imagine there must be a programmatic switch for this?

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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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• 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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• Java Hibernate Lazy=false

  - by Noor

  When setting Lazy=false, then hibernate will automatically loads the objects into the required sets e.g. <set name="Options" table="ATTRIBUTEOPTION" inverse="false" cascade="all" lazy="false"> <key> <column name="ATTRIBUTEID" /> </key> <one-to-many class="com.BiddingSystem.Models.AttributeOption" /> </set> but if in my xml mapping, I place lazy=true and in some place in my application i decide that i want to load all attribute options, should i do it manually, or is there a technique which lets tells hibernate that now i want to set lazy=false??

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• Why do I have to explicitly cast sometimes for varargs?

  - by Daniel Lew

  I've got a Class that uses reflection a lot, so I wrote a method to help out: private <T> T callMethod(String methodName, Class[] parameterTypes, Object[] args) { try { Class c = mVar.getClass(); Method m = c.getMethod(methodName, (Class[]) parameterTypes); return (T) m.invoke(mVar, args); } // Insert exception catching here [...] } This worked well for any method that had parameters, however I had to explicitly cast parameterTypes to Class[] in order for this to work for methods with no parameters (e.g., callMethod('funName', null, null);). I've been trying to figure out why this is the case. It seems to me that if parameterTypes, when null, had no concept of what type it is (Class[]), then I'd need to cast it for getMethod(). But if that's the case, why is getMethod() able to tell the difference between null, and (Class[]) null when the method is invoked?

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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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• Using jQuery, how do I way attach a string array as a http parameter to a http request?

  - by predhme

  I have a spring controller with a request mapping as follows @RequestMapping("/downloadSelected") public void downloadSelected(@RequestParam String[] ids) { // retrieve the file and write it to the http response outputstream } I have an html table of objects which for every row has a checkbox with the id of the object as the value. When they submit, I have a jQuery callback to serialize all ids. I want to stick those ids into an http request parameter called, "ids" so that I can grab them easily. I figured I could do the following var ids = $("#downloadall").serializeArray(); Then I would need to take each of the ids and add them to a request param called ids. But is there a "standard" way to do this? Like using jQuery?

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• Is there an equivalent to C++'s "friend class" in Java?

  - by Ricket

  In C++ there is a concept of a "friend", which has access to a class's private variables and functions. So if you have: class Foo { friend class Bar; private: int x; } then any instance of the class Bar can modify any Foo instance's x member, despite it being private, because Bar is a friend of Foo. Now I have a situation in Java where this functionality would come in handy. There are three classes: Database, Modifier, Viewer. The Database is just a collection of variables (like a struct). Modifier should be "friends" with Database; that is, it should be able to read and write its variables directly. But Viewer should only be able to read Database's variables. How is this best implemented? Is there a good way to enforce Viewer's read-only access of Database?

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• How do I get the NextVal from an oracle Sequence thru NHibernate

  - by trainer

  I am working on c# .net 4.0 and using NHibernate to talk with an Oracle DB. You would think something as simple as this is already addressed somewhere but sadly its not. I need the NextVal from an Oracle sequence. I do not need to insert it a database as part of an Id or Primary key. I just need to use the next val on the c# side. Can somebody help me out with xml mapping and C# file(or a link) to achieve this. Thanks. Something like int NextValueOfSequence = GetNextValueofSequence(); public int GetNextValueOfSequence() { // Access NHibernate to return the next value of the sequence. }

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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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• In DirectShow, what determines the graph source?

  - by Seva Alekseyev

  Hi all, I have two machines - A (XP SP2) and B (Win7). Machine B has trouble playing OGM files - enabling subtitles causes a crash in the player. Investigation shows that the DirectShow graphs are quite different. On A, the source is a file source, which produces a stream of subtype OGG, which goes into "Ogg Splitter". On B, the source is an instance of Haali Media Splitter, which produces video, audio, and subtitles as separate streams. Machine A has Haali splitter installed as well, but it is not invoked somehow. Question - what determines the source filter? Is there a file type to preferred source mapping, or does the system load and ask all suitable filters if they would take this file? On machine A, the merit of Haali splitter is higher than that of File source, so it's probably not about relative merits.

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