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  • How to handle choice field with JPA 2, Hibernate 3.5

    - by phmr
    I have an entity with Integer attributes that looks like this in proto code: class MyEntity: String name Integer frequency Integer type def getFrequency() def getType() get* accessors return strings according to this table. value(type) HumanReadableString(type) 1 BSD 2 Apache 3 GPL min frequency max frequency HumanReadableString(frequency) 0 1000 rare 1000 2000 frequent 2001 3000 sexy It should be possible to get all possible values that an attribute can take, example: getChoices(MyEntity, "type") returns ("rare", "frequent", "sexy") It should be possible to get the bound value from the string: getValue(MyEntity, "frequency", "sexy") returns (2000,3000)

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  • Should a Trim method generally in the Data Access Layer or with in the Domain Layer?

    - by jpierson
    I'm dealing with a database that contains data with inconsistencies such as white leading and trailing white space. In general I see a lot of developers practice defensive coding by trimming almost all strings that come from the database that may have been entered by a user at some point. In my oppinoin it is better to do such formating before data is persisted so that it is done only once and then the data can be in a consistent and reliable state. Unfortunatley this is not the case however which leads me to the next best solution, using a Trim method. If I trim all data as part of my data access layer then I don't have to concern myself with defensive trimming within the business objects of my domain layer. If I instead put the trimming responsibility in my business objects, such as with set accessors of my C# properties, I should get the same net results however the trim will be operating on all values assigned to my business objects properties not just the ones that come from the inconsistent database. I guess as a somewhat philisophical question that may determine the answer I could ask "Should the domain later be responsible for defensive/coercive formatting of data?" Would it make sense to have a set accessor for a PhoneNumber property on a business object accept a unformatted or formatted string and then attempt to format it as required or should this responsibility be pushed to the presentation and data access layers leaving the domain layer more strict in the type of data that it will accept? I think this may be the more fundamental question. Update: Below are a few links that I thought I should share about the topic of data cleansing. Information service patterns, Part 3: Data cleansing pattern LINQ to SQL - Format a string before saving? How to trim values using Linq to Sql?

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  • Determine if Alpha Channel is Used in an Image

    - by Otaku
    As I'm bringing in images into my program, I want to determine if: they have an alpha-channel if that alpha-channel is used #1 is simple enough with using Image.IsAlphaPixelFormat. For #2 though, other than looping through every single pixel, is there a simple way I can determine if at least one of the pixels has an alpha channel that is used (i.e. set to some other value than 255)? All I need back is a boolean and then I'll make determination as to whether to save it out to 32-bit or 24-bit.

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  • Create a Stream without having a physical file to create from.

    - by jhorton
    I'm needing to create a zip file containing documents that exist on the server. I am using the .Net Package class to do so, and to create a new Package (which is the zip file) I have to have either a path to a physical file or a stream. I am trying to not create an actual file that would be the zip file, instead just create a stream that would exist in memory or something. My question is how do you instantiate a new Stream (i.e. FileStream, MemoryStream, etc) without having a physical file to instantiate from.

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  • Cleansing string / input in Coldfusion 9

    - by Jakub
    I have been working with Coldfusion 9 lately (background in PHP primarily) and I am scratching my head trying to figure out how to 'clean/sanitize' input / string that is user submitted. I want to make it HTMLSAFE, eliminate any javascript, or SQL query injection, the usual. I am hoping I've overlooked some kind of function that already comes with CF9. Can someone point me in the proper direction?

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  • Silverlight Data Binding for Collection in Stack Panel

    - by Blake Blackwell
    I'm new to Silverlight, so I don't have a complete grasp of all the controls at my disposal. What I would like to do is use databinding and a view model to maintain a collection of items. Here is some mock code for what I'd like to do: Model public class MyItem { public string DisplayText { get; set; } public bool Enabled { get; set; } } ViewModel public class MyViewModel : INotifyPropertyChanged { private ObservableCollection<MyItem> _myItems = new ObservableCollection<MyItem>(); public ObservableCollection<MyItem> MyItems { get { return _myItems; } set { _myItems = value NotifyPropertyChanged(this, "MyItems"); } } } View <Grid x:Name="LayoutRoot" Background="White"> <StackPanel ItemsSource="{Binding MyItems}"> <StackPanel Orientation="Horizontal"> <CheckBox "{Binding Enabled, Mode=TwoWay}"></CheckBox> <TextBlock Text="{Binding DisplayText, Mode=TwoWay}" /> </StackPanel> </StackPanel> </Grid> So my end goal would be that every time I add another MyItem to the MyItems collection it would create a new StackPanel with checkbox and textblock. I don't have to use a stack panel but just thought I'd use that for this sample.

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  • How to bind a complex dictionary to a Gridview in asp.net?

    - by Mehdi
    I've used an early binding of a dictionary<string, string> to a gridview to show Urls Text and its HRef as key-value and it works like a charm. But since I want to replace the dictionary with this one : dictionary<string, LinkInfo> the binding goes wrong! Should I handle some events like as onItemDataBound or something? and the LinkInfo structure is: public struct LinkInfo{ public string href; public bool Enabled; }

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  • Implementing simple business model in Haskell

    - by elmes
    Supose we have a very simple model: Station has at least one Train Train has at least two Stations The model has to allow to check what stations any given train visits and to check what trains visit a particular station. How to model it in Haskell? I am a Haskell newbie, so please correct me: once an object is created, you cannot modify it - you can only make a new object based on that one (~immutability). Am I right? If so, I'll have to create a lot of temporary variables with semi-initialized objects (during deserialization or even in unit tests). Basically what I need is an example of modeling domain classes in Haskell - after reading "Learn you a haskell.." I still have no idea how to use this language.

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  • symfony 2 verify type of data stored in a single column

    - by GRafoKI
    In my DB I have a column 'own_product' that contains 2 values ( quantity and name) In my Edit form I want to check if the first field (quantity) is string and positive or not. I added a new column 'type-prod' (int , string) this is my controller : $request = $this->container->get('request'); if ($request->getMethod() == 'POST') { $formel = $request->query->get('edit_formal'); $type_value = $formel['own_product']; //case int $type_int= $this ->getDoctrine() ->getEntityManager() ->getRepository('DHG\WelcomeBundle\Entity\type-prod') ->findOneBy(array('type' => 'int')); //case string $type_string = $this ->getDoctrine() ->getEntityManager() ->getRepository('DHG\WelcomeBundle\Entity\type-prod') ->findOneBy(array('type' => 'string')); if (isset($type_value) && $type_int && $type_value > 0 && is_int($type_value)) { echo 'Success'; } else echo 'error' ; } Thank you !

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  • Best Book on Operating Systems

    - by qp
    What is the best, up-to-date and comprehensive book on operating systems? Voice your opinion. I have seen recommendations for Tanenbaum's Modern Operating Systems but the reviews saying the latest edition has many conceptual errors and numerous typos make me worry.

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  • Calculated group-by fields in MongoDB

    - by Navin Viswanath
    For this example from the MongoDB documentation, how do I write the query using MongoTemplate? db.sales.aggregate( [ { $group : { _id : { month: { $month: "$date" }, day: { $dayOfMonth: "$date" }, year: { $year: "$date" } }, totalPrice: { $sum: { $multiply: [ "$price", "$quantity" ] } }, averageQuantity: { $avg: "$quantity" }, count: { $sum: 1 } } } ] ) Or in general, how do I group by a calculated field?

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  • how to store/model users/faceboook users/linkedin users, etc, with ActiveRecord?

    - by crankharder
    My app has "normal" users: those which come through a typical signup page facebook(FB) users: those which come from Facebook connect "FB-normal" users: a user that can log with both email/password * FB connect Further, there's the a slew of other openID-ish login methods (I don't think openID itself will be acceptable since it doesn't link up the accounts and allow the 3rd party specific features (posting to twitter, adding a FB post, etc etc)) So, how do I model this? Right now we have User class with #facebook_user? defined -- but it gets messy with the "FB-normal" users - plus all the validations become very tricky and hard to interpret. Also, there are methods like #deliver_password_reset! which make no sense in the context for facebook-only users. (this is lame) I've thought out STI (User::Facebook, User::Normal, User::FBNormal, etc.) This makes validations super slick, but it doesn't scale to other connection types, and all the permutations between them... User::FacebookLinkedInNormal(wtf?) Doing this with a bunch of modules I think would suck a lot. Any other ideas?

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  • Strategy to structure a search index in a relational database

    - by neilc
    I am interested in suggestions for building an efficient and robust structure for indexing products in a new database I am building (i'm using MySql) When a product is entered through the form there are three parts I am interested in indexing for searching purposes. The product title The product description Tags The most important is title, followed by tags, followed by the description. I was thinking of using the following structure CREATE TABLE `searchindex` ( `id` INT NOT NULL , `word` VARCHAR( 255 ) NOT NULL , `weighting` INT NOT NULL , `product_id` INT NOT NULL , PRIMARY KEY ( `id` ) ) Then each time a product is created I would split apart the title, description and tags (removing common words) and award them a weighting. Then it is trivial to select out the words and corresponding products and order them by weighting. Is there a better way to do this? I would be worried that this strategy would slow down over time and as the database filled up.

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  • Transfer of control and data between C and C#

    - by Prithvi
    C# main program needs to call a C program GA.c This C code executes many functions and one function initialize() calls objective() function. But this objective function needs to be written in C#.This call is in a loop in the C code and the C code needs to continue execution after the return from objective() until its main is over and return control to C# main program. C# main() { //code call to GA in C; //remaining code; } GA in C: Ga Main() { //code call to initialize function(); //remaining code } initialize funtion() in GA { for(some condition) { //code call to objective(parameter) function in C#; //code } } How do we do this?

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  • Insert data in an object to a database.

    - by paul
    I am facing the following design/implementation dilemma. I have a class Customer which is below with getters and setters. I would like to insert the value of the Customer into a "Customer" table of a database. But Customer has an address which is of type "Address". How do I go about inserting this field into the database?(I am using sqlite3). I thought of writing a separate table "Address(customerId,doorNo,city,state,country,pinCode)". But I am having second thoughts about generating the primary key(customerId) which should be same for both the "customer" and "Address" table. Sqlite3 faq states that I can do "Integer Primary Key" to use the field to generate an auto number. But if I do that in customer table, I would have to retrieve the same Id to be used in Address table. This kinda looks wrong to me :-?. There should be an elegant method to solve this. Any ideas would be much appreciated. Thanks in advance. import java.io.*; import java.sql.*; class Customer { private String id; private String name; private Address address; private Connection connection; private ResultSet resultSet; private PreparedStatement preparedStatement; public void insertToDatabase(){ } } class Address{ private String doorNumber; private String streetName; private String cityName; private String districtName; private String stateName; private String countryName; private long pinCode; }

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  • Why doesn't this data binding work?

    - by Qwertie
    I have a ViewModel class that contains a list of points, and I am trying to bind it to a Polyline. The Polyline picks up the initial list of points, but does not notice when additional points are added even though I implement INotifyPropertyChanged. What's wrong? <StackPanel> <Button Click="Button_Click">Add!</Button> <Polyline x:Name="_line" Points="{Binding Pts}" Stroke="Black" StrokeThickness="5"/> </StackPanel> C# side: // code-behind _line.DataContext = new ViewModel(); private void Button_Click(object sender, RoutedEventArgs e) { // The problem is here: NOTHING HAPPENS ON-SCREEN! ((ViewModel)_line.DataContext).AddPoint(); } // ViewModel class public class ViewModel : INotifyPropertyChanged { public event PropertyChangedEventHandler PropertyChanged; public PointCollection Pts { get; set; } public ViewModel() { Pts = new PointCollection(); Pts.Add(new Point(1, 1)); Pts.Add(new Point(11, 11)); } public void AddPoint() { Pts.Add(new Point(25, 13)); if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs("Pts")); } }

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  • Sending files using Winsock - optimal send() data length?

    - by Meta
    I am using Winsock with non-blocking sockets to send a file to a client. The way I'm doing it right now is that I read a chunk of 8192 bytes from the file, and then loop until all of it successfully goes through send() (obviously handling WSAEWOULDBLOCK as it occurs). I then move on and read the next 8192 bytes, and so on... Although I can use any other number than 8192 when I test the transfer on my local machine, once I try it over a network, it seems like 8191 is the largest number I can use. When I try to use any number higher than 8191 (starting with 8192), the file transfer becomes extremely slow (about 5 times slower). Is there any reason why 8191 is so special? I've done some more testing and it turns out that using 8000 is slightly faster (by 0.5%). If you understand why 8191 is so special, can you tell me if there is a number better than the others (better than 8000)? I have a feeling that it has something to do with the fact that the default send buffer allocated to the socket by Winsock is 8KB, but I don't understand why. It might also have something to do with the Nagle algorithm, but again, I'm not sure how. Note that I have not modified the SO_SNDBUF option nor the TCP_NODELAY option. Or am I doing this all wrong? What's the best way of sending a file over a non-blocking socket?

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  • How can I get an IObservable<T> in Rx from a "non-standard" event?

    - by Dan Tao
    Here's what I mean. Suppose I'm working with an API that exposes events, but these events do not follow the standard EventHandler or EventHandler<TEventArgs> signature. One event might look like this, for instance: Public Event Update(ByVal sender As BaseSubscription, ByVal e As BaseEvent) Now, typically, if I want to get an IObservable<TEventArgs> from an event, I can just do this: Dim updates = Observable.FromEvent(Of UpdateEventArgs)( _ target:=updateSource, _ eventName:="Update" _ ) But this doesn't work, because the Update event is not an EventHandler<UpdateEventArgs> -- in fact, there is no UpdateEventArgs -- it's basically just its own thing. Obviously, I could define my own class deriving from EventArgs (i.e., UpdateEventArgs), write another class to wrap the object providing the Update event, give the wrapper class its own Update event that is an EventHandler<UpdateEventArgs>, and get an IObservable<UpdateEventArgs> from that. But that's an annoying amount of work. Is there some way to create an IObservable<[something]> from a "non-standard" event like this, or am I out of luck?

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  • how to Invoke User-Defined Functions That Return a Table Data Type

    - by nectar
    here my code- create function dbo.emptable() returns Table as return (select id, name, salary from employee) go select dbo.emptable() error: Msg 4121, Level 16, State 1, Line 1 Cannot find either column "dbo" or the user-defined function or aggregate "dbo.emptable", or the name is ambiguous. while when I run sp_helptext emptable it shows- create function dbo.emptable() returns Table as return (select id, name, salary from employee) it means function exists in database then why it is giving such error?

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  • Model a Zero or One to Many Relationship

    - by John
    How should I model a zero or one to a many relationship in the database? For example, a user record may or may not have a parent. So should my user table have a t_user.parent_id or should I have an associative table called t_user_hierarchy with the columns t_user_hierarchy.parent_id and t_user_hierarchy.user_id?

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  • Encapsulating user input of data for a class (C++)

    - by Dr. Monkey
    For an assignment I've made a simple C++ program that uses a superclass (Student) and two subclasses (CourseStudent and ResearchStudent) to store a list of students and print out their details, with different details shown for the two different types of students (using overriding of the display() method from Student). My question is about how the program collects input from the user of things like the student name, ID number, unit and fee information (for a course student) and research information (for research students): My implementation has the prompting for user input and the collecting of that input handled within the classes themselves. The reasoning behind this was that each class knows what kind of input it needs, so it makes sense to me to have it know how to ask for it (given an ostream through which to ask and an istream to collect the input from). My lecturer says that the prompting and input should all be handled in the main program, which seems to me somewhat messier, and would make it trickier to extend the program to handle different types of students. I am considering, as a compromise, to make a helper class that handles the prompting and collection of user input for each type of Student, which could then be called on by the main program. The advantage of this would be that the student classes don't have as much in them (so they're cleaner), but also they can be bundled with the helper classes if the input functionality is required. This also means more classes of Student could be added without having to make major changes to the main program, as long as helper classes are provided for these new classes. Also the helper class could be swapped for an alternative language version without having to make any changes to the class itself. What are the major advantages and disadvantages of the three different options for user input (fully encapsulated, helper class or in the main program)?

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