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  • What ORMs work well with Scala?

    - by Clinton R. Nixon
    I'm about to write a Scala command-line application that relies on a MySQL database. I've been looking around for ORMs, and am having trouble finding one that will work well. The Lift ORM looks nice, but I'm not sure it can be decoupled from the entire Lift web framework. ActiveObjects also looks OK, but the author says that it may not work well with Scala. I'm not coming to Scala from Java, so I don't know all the options. Has anyone used an ORM with Scala, and if so, what did you use and how well did it work?

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  • How do I initialize attributes when I instantiate objects in Rails?

    - by nfm
    Clients have many Invoices. Invoices have a number attribute that I want to initialize by incrementing the client's previous invoice number. For example: @client = Client.find(1) @client.last_invoice_number > 14 @invoice = @client.invoices.build @invoice.number > 15 I want to get this functionality into my Invoice model, but I'm not sure how to. Here's what I'm imagining the code to be like: class Invoice < ActiveRecord::Base ... def initialize(attributes = {}) client = Client.find(attributes[:client_id]) attributes[:number] = client.last_invoice_number + 1 client.update_attributes(:last_invoice_number => client.last_invoice_number + 1) end end However, attributes[:client_id] isn't set when I call @client.invoices.build. How and when is the invoice's client_id initialized, and when can I use it to initialize the invoice's number? Can I get this logic into the model, or will I have to put it in the controller?

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  • Why is it bad to use boolean flags in databases? And what should be used instead?

    - by David Chanin
    I've been reading through some of guides on database optimization and best practices and a lot of them suggest not using boolean flags at all in the DB schema (ex http://forge.mysql.com/wiki/Top10SQLPerformanceTips). However, they never provide any reason as to why this is bad. Is it a peformance issue? is it hard to index or query properly? Furthermore, if boolean flags are bad, what should you use to store boolean values in a database? Is it better to store boolean flags as an integer and use a bitmask? This seems like it would be less readable.

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  • Are GUID primary keys bad in theory, or just practice?

    - by Yarin
    Whenever I design a database I automatically start with an auto-generating GUID primary key for each of my tables (excepting look-up tables) I know I'll never lose sleep over duplicate keys, merging tables, etc. To me it just makes sense philosophically that any given record should be unique across all domains, and that that uniqueness should be represented in a consistent way from table to table. I realize it will never be the most performant option, but putting performance aside, I'd like to know if there are philosophical arguments against this practice?

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  • c# object instantiation

    - by user1112111
    What's the difference between: Object o = new Object(); o.foo(); and new Object().foo(); (assuming I do not need the reference afterwards) ? Are there any reasons for using one instead of the other one (e.g. memory usage) ?

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  • c# send recive object over network?

    - by Data-Base
    Hello, I'm working on a server/client project the client will be asking the server for info and the server will send them back to the client the info may be string,number, array, list, arraylist or any other object I found allot of examples but I faced issues!!!! the solution I found so far is to serialize the object (data) and send it then de-serialize it to process here is the server code public void RunServer(string SrvIP,int SrvPort) { try { var ipAd = IPAddress.Parse(SrvIP); /* Initializes the Listener */ if (ipAd != null) { var myList = new TcpListener(ipAd, SrvPort); /* Start Listeneting at the specified port */ myList.Start(); Console.WriteLine("The server is running at port "+SrvPort+"..."); Console.WriteLine("The local End point is :" + myList.LocalEndpoint); Console.WriteLine("Waiting for a connection....."); while (true) { Socket s = myList.AcceptSocket(); Console.WriteLine("Connection accepted from " + s.RemoteEndPoint); var b = new byte[100]; int k = s.Receive(b); Console.WriteLine("Recieved..."); for (int i = 0; i < k; i++) Console.Write(Convert.ToChar(b[i])); string cmd = Encoding.ASCII.GetString(b); if (cmd.Contains("CLOSE-CONNECTION")) break; var asen = new ASCIIEncoding(); // sending text s.Send(asen.GetBytes("The string was received by the server.")); // the line bove to be modified to send serialized object? Console.WriteLine("\nSent Acknowledgement"); s.Close(); Console.ReadLine(); } /* clean up */ myList.Stop(); } } catch (Exception e) { Console.WriteLine("Error..... " + e.StackTrace); } } here is the client code that should return an object public object runClient(string SrvIP, int SrvPort) { object obj = null; try { var tcpclnt = new TcpClient(); Console.WriteLine("Connecting....."); tcpclnt.Connect(SrvIP, SrvPort); // use the ipaddress as in the server program Console.WriteLine("Connected"); Console.Write("Enter the string to be transmitted : "); var str = Console.ReadLine(); Stream stm = tcpclnt.GetStream(); var asen = new ASCIIEncoding(); if (str != null) { var ba = asen.GetBytes(str); Console.WriteLine("Transmitting....."); stm.Write(ba, 0, ba.Length); } var bb = new byte[2000]; var k = stm.Read(bb, 0, bb.Length); string data = null; for (var i = 0; i < k; i++) Console.Write(Convert.ToChar(bb[i])); //convert to object code ?????? Console.ReadLine(); tcpclnt.Close(); } catch (Exception e) { Console.WriteLine("Error..... " + e.StackTrace); } return obj; } I need to know a good serialize/serialize and how to integrate it into the solution above :-( I would be really thankful for any help cheers

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  • What can map database tables like LINQ to SQL did?

    - by trnTash
    A good thing in LINQ to SQL was a fast and reliable way to map database tables and convert them into classes accessible from c# project. However it is no longer recommended to create projects using LINQ to SQL. What is its substitute? What kind of tool should I use in VS 2010 today if I want to have the same functionality as I had with LINQ to SQL?

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  • Python: Getting the attribute name that the created object will be given

    - by cool-RR
    Before I ask this, do note: I want this for debugging purposes. I know that this is going to be some bad black magic, but I want to use it just during debugging so I could identify my objects more easily. It's like this. I have some object from class A that creates a few B instances as attributes: class A(object): def __init__(self) self.vanilla_b = B() self.chocolate_b = B() class B(object): def __init__(self): # ... What I want is that in B.__init__, it will figure out the "vanilla_b" or whatever attribute name it was given, and then put that as the .name attribute to this specific B. Then in debugging when I see some B object floating around, I could know which one it is. Is there any way to do this?

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  • Using a c# .net object in an Excel VBA form

    - by Mark O'G
    Hi I have a .net object that I want to use in Excel. I have an existing VBA script that i need to alter to call this the object from. I have then converted the object to a TLB. I've not really touched on this area before so any help will be appreciated. I have created an interface [Guid("0F700B48-E0CA-446b-B87E-555BCC317D74"),InterfaceType(ComInterfaceType.InterfaceIsDual)] public interface IOfficeCOMInterface { [DispId(1)] void ResetOrder(); [DispId(2)] void SetDeliveryAddress(string PostalName, string AddressLine1, string AddressLine2, string AddressLine3, string AddressLine4, string PostCode, string CountryCode, string TelephoneNo, string FaxNo, string EmailAddress); } I have also created an class that inherits that object. [ClassInterface(ClassInterfaceType.None), ProgId("NAMESPACE.OfficeCOMInterface"), Guid("9D9723F9-8CF1-4834-BE69-C3FEAAAAB530"), ComVisible(true)] public class OfficeCOMInterface : IOfficeCOMInterface, IDisposable { public void ResetSOPOrder() { } public void SetDeliveryAddress(string PostalName, string AddressLine1, string AddressLine2, string AddressLine3, string AddressLine4, string PostCode, string CountryCode, string TelephoneNo, string FaxNo, string EmailAddress) { try { SalesOrder.AmendDeliveryAddress(PostalName, AddressLine1, AddressLine2, AddressLine3, AddressLine4, PostCode); MessageBox.Show("Delivery address set"); } catch (Exception ex) { throw ex; } } }

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  • Suggestions on documentation of a DB model when using Entity Framework 4

    - by Junior Ewing
    Any experiences on how to document Entity Framework 4 based Database projects? There is the Document and Summary properties on the Entities, but if we want to regenerate the model from the database at some point, it will be lost! Is there some way to map documentation data inside SQL to the Entities in the EDMX file so it is safe. Suggestions of other best practices? Ideally I want to be able to augo generate html/helpfile documentation from the DB when we deploy.

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  • How to use OCL constraints to prevent node creation in an GMF generated editor

    - by TheMorph
    Hello, I am working on editors created with GMF and struggling with OCL right now. Is there a possibilty to prevent a node to be created if an OCL statement in the mapping evaluates to false? If tried adding an OCL statement to a node and all it does is making the node not visible in the editor, but it is created. There is also an OCL statement in the ecore file, but this way it is only evaluated when there should be something done with the created model. I does not prevent a user to construct an invalid model but this is what I intend to prevent. Thanks in advance, Morph

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  • C++ return a "NULL" object if search result not found

    - by aduric
    I'm pretty new to C++ so I tend to design with a lot of Java-isms while I'm learning. Anyway, in Java, if I had class with a 'search' method that would return an object T from a Collection< T that matched a specific parameter, I would return that object and if the object was not found in the collection, I would return a NULL. Then in my calling function I would just check if(T != NULL) { ... } In C++, I'm finding out that I can't return a NULL if the object doesn't exist. I just want to return an 'indicator' of type T that notifies the calling function that no object has been found. I don't want to throw an exception because it's not really an exceptional circumstance. class Node { .... Attr& getAttribute(const string& attribute_name) const { //search collection //if found at i return attributes[i]; //if not found return NULL; } private: vector<Attr> attributes; }

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  • Get Excel.Application object from Process or hwnd in .NET

    - by Abiel
    In C# I am trying to get an instance of an Excel.Application object from a Process object. This seems like it should be really simple yet I cannot figure it out and cannot find an example. To repeat, I have a System.Diagnostics.Process object that I know refers to a running Excel instance. I now need to recover a Microsoft.Office.Interop.Excel.Application object that refers to the process so that I can go about manipulating the Excel application from C#. In case it makes it any simpler, I also have the HWND id and window text associated with the active Excel window. Thanks.

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  • How to code a C# Extension method to turn a Domain Model object into an Interface object?

    - by Dr. Zim
    When you have a domain object that needs to display as an interface control, like a drop down list, ifwdev suggested creating an extension method to add a .ToSelectList(). The originating object is a List of objects that have properties identical to the .Text and .Value properties of the drop down list. Basically, it's a List of SelectList objects, just not of the same class name. I imagine you could use reflection to turn the domain object into an interface object. Anyone have any suggestions for C# code that could do this? The SelectList is an MVC drop down list of SelectListItem. The idea of course is to do something like this in the view: <%= Html.DropDownList("City", (IEnumerable<SelectListItem>) ViewData["Cities"].ToSelectList() )

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  • How to integrate an dynamically generated JSON Object into an other object?

    - by Marco Ciarfaglia
    How can I put this JSON Object in the function or object below? // this function generates an JSON Object dynamically $(".n_ListTitle").each(function(i, v) { var node = $(this); var nodeParent = node.parent(); var nodeText = node.text(); var nodePrice = node.siblings('.n_ListPrice'); var prodPrice = $(nodePrice).text(); var prodId = nodeParent.attr('id').replace('ric', ''); var prodTitle = nodeText; var json = { id : prodId, price : prodPrice, currency : "CHF", name : prodTitle }; return json; }); TDConf.Config = { products : [ // here should be inserted the JSON Object {id: "[product-id1]", price:"[price1]", currency:"[currency1]", name:"[product-name1]"}, {id: "[product-id2]", price:"[price2]", currency:"[currency2]", name:"[product-name2]"}, ... })], containerTagId :"..." }; If it is not understandable please ask :) Thanks in advance for helping me to figure out!

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  • Alternative or succesor to GDBM

    - by Anon Guy
    We a have a GDBM key-value database as the backend to a load-balanced web-facing application that is in implemented in C++. The data served by the application has grown very large, so our admins have moved the GDBM files from "local" storage (on the webservers, or very close by) to a large, shared, remote, NFS-mounted filesystem. This has affected performance. Our performance tests (in a test environment) show page load times jumping from hundreds of milliseconds (for local disk) to several seconds (over NFS, local network), and sometimes getting as high as 30 seconds. I believe a large part of the problem is that the application makes lots of random reads from the GDBM files, and that these are slow over NFS, and this will be even worse in production (where the front-end and back-end have even more network hardware between them) and as our database gets even bigger. While this is not a critical application, I would like to improve performance, and have some resources available, including the application developer time and Unix admins. My main constraint is time only have the resources for a few weeks. As I see it, my options are: Improve NFS performance by tuning parameters. My instinct is we wont get much out of this, but I have been wrong before, and I don't really know very much about NFS tuning. Move to a different key-value database, such as memcachedb or Tokyo Cabinet. Replace NFS with some other protocol (iSCSI has been mentioned, but i am not familiar with it). How should I approach this problem?

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  • 3d model viewer in Flash or Java

    - by Magnetic_dud
    I want to show a box in 3d on my website, and I was thinking to do it in Flash. How I can show a 3d model? I need something very simple, it's a textured cube, no interaction required, just let the user pan and zoom. There is a 3ds viewer in flash or something like that? Java is also ok (but flash is preferred)

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  • Problem with object serialization in Applet-Servlet communication

    - by Bruce
    Hi guys, I spent a lot of time on thinking what is wrong with the following code. I send the object from my applet to servlet and then I read the object from servlet. Everything goes fine till reading serialized object from the servlet - I got IOException. Thank you in advance! Here is the code: Applet: try { URL servletURL = new URL(this.getCodeBase().getProtocol(), this.getCodeBase().getHost(), this.getCodeBase().getPort(), "/MyApplet"); URLConnection servletConnection = servletURL.openConnection(); servletConnection.setDoInput( true ); servletConnection.setDoOutput( true ); servletConnection.setUseCaches( false ); servletConnection.setRequestProperty( "Content-Type", "application/x-java-serialized-object" ); ObjectOutputStream output; output = new ObjectOutputStream( servletConnection.getOutputStream( ) ); output.writeObject( someObject ); output.flush( ); output.close( ); ObjectInputStream input = new ObjectInputStream( servletConnection.getInputStream( ) ); // Here I got the exception myObject = ( SomeObject ) input.readObject( ); } catch (java.io.IOException ioe) { System.err.println(ioe.getStackTrace()); } catch (Exception e) { System.err.println(e.getStackTrace()); } Servlet: response.setContentType("application/x-java-serialized-object"); try { ObjectInputStream inputFromApplet = new ObjectInputStream(request.getInputStream()); SomeObject myObject = (SomeObject) inputFromApplet.readObject(); ObjectOutputStream outputToApplet = new ObjectOutputStream(response.getOutputStream()); outputToApplet.writeObject(myObject); outputToApplet.flush(); } catch(Exception e) { // ... }

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  • c#3.5 Deserialization error - object reference not set

    - by BBR
    I am trying to deserialize an xml string in c#3.5, the code below does work in c# 4.0. When I try to run in the code in c#3.5 I get an Object reference not set to an instance of an object exception when the code tries in initialize the XmlSerializer. Any help would be appreciated. string xml = "<boolean xmlns=\"http://schemas.microsoft.com/2003/10/serialization/\">false</boolean>"; var xSerializer = new XmlSerializer(typeof(bool), null, null, new XmlRootAttribute("boolean"), "http://schemas.microsoft.com/2003/10/serialization/"); using (var sr = new StringReader(xml)) using (var xr = XmlReader.Create(sr)) { var y = xSerializer.Deserialize(xr); } System.NullReferenceException was unhandled Message="Object reference not set to an instance of an object." Source="System.Xml" StackTrace: at System.Xml.Serialization.XmlSerializer..ctor(Type type, XmlAttributeOverrides overrides, Type[] extraTypes, XmlRootAttribute root, String defaultNamespace, String location, Evidence evidence) at System.Xml.Serialization.XmlSerializer..ctor(Type type, XmlAttributeOverrides overrides, Type[] extraTypes, XmlRootAttribute root, String defaultNamespace) .... at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args) at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly() at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.ThreadHelper.ThreadStart() InnerException:

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  • PHP: How to access array values returned by a static function?

    - by Prashant
    I am running following code, getAccount() is a static function, $ac_info = AccountClass::getAccount($ac_code); print_r($ac_info); and getting following output AccountClass Object ( [account_code] => [email protected] [username] => XYZ [email] => [first_name] => [last_name] => [company_name] => [id] => [email protected] [balance_in_cents] => 0 [created_at] => 1271333048 [state] => active ) But I want to access the value of "account_code" shown above, how to access it, and AccountClass Object what is this, this is array or what? I am not getting it properly. Please explain what is AccountClass Object and how to access value of properties account_code, first_name inside this array. Thanks

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  • Cannot export a fusionchart with 'Embedding Charts Using <OBJECT>/<EMBED> Tags'

    - by zoom_pat277
    I am trying to export a fusion chart created using 'Embedding Charts Using / Tags'. Export works just perfect with the right click (on the chart) and chose a pdf to export. But I am not able to make this work via javascript. I have a button outside the chart which upon clicking calls the function below function myexport() { var object = getChartFromId('myChartid'); if( object.hasRendered() ) object.exportChart({exportFormat: 'PDF'}); } the object above returned is null and this fails on the next line here is the full prototype <html> <head> <title>My Chart</title> <script type="text/javascript" src="fusionCharts.debug.js"></script> <script type="text/javascript" src="fusionChartsExportComponent.js"></script> <script type="text/javascript"> function ExportMyChart() { var cObject = getChartFromId('Column3D'); if( cObject.hasRendered() ) cObject.exportChart({exportFormat: 'PDF'}); } </script> </head> <body> <object width="400" height="400" id="Column3D" classid="clsid:d27cdb6e-ae6d-11cf-96b8-444553540000" codebase="http://fpdownload.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=8,0,0,0" > <param name="testname" value="Column3D.swf" /> <param name="FlashVars" value="&dataURL=testData.xml&chartWidth=400&chartHeight=300&DOMId=myChart1&registerWithJS=1&debugMode=0"> <param name="quality" value="high" /> <embed src="Column3D.swf" flashVars="&dataURL=testData.xml&chartWidth=400&chartHeight=300&DOMId=myChart1&registerWithJS=1&debugMode=0" width="400" height="300" name="Column3D" quality="high" type="application/x-shockwave-flash" pluginspage="http://www.macromedia.com/go/getflashplayer" /> </object> <!-- We also create a DIV to contain the FusionCharts client-side exporter component --> <div id="holderDiv" align="center">FusionCharts Export Handler Component</div> <script type="text/javascript"> var myExportComponent = new FusionChartsExportObject("testExporter1", "FCExporter.swf"); //Render the exporter SWF in our DIV fcexpDiv myExportComponent.Render("holderDiv"); </script> <input type="button" value="Export My Chart" onclick="ExportMyChart()" />

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  • How to "uninstantiate" an object?

    - by Mark
    I wrote a function in Python: def instantiate(c): if inspect.isclass(c): return c() elif isinstance(c, object): return c else: raise Exception, '%s is not an object or class.' % c Now I want to do the opposite: get the class from an already instantiated object so that I can re-instantiate it with different parameters. How can I do that?

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  • Typed DefaultListModel to avoid casting

    - by Thomas R.
    Is there a way in java to have a ListModel that only accepts a certain type? What I'm looking for is something like DefaultListModel<String> oder TypedListModel<String>, because the DefaultListModel only implements addElement(Object obj) and get(int index) which returns Object of course. That way I always have to cast from Object to e.g. String and there is no guarantee that there are only strings in my model, even though I'd like to enforce that. Is this a flaw or am I using list models the wrong way?

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