Search Results

Search found 32789 results on 1312 pages for 'object relational mapping'.

Page 107/1312 | < Previous Page | 103 104 105 106 107 108 109 110 111 112 113 114  | Next Page >

• 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?

  Read the article

• 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?

  Read the article

• 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

  Read the article

• 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; }

  Read the article

• 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.

  Read the article

• 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; } } }

  Read the article

• 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()" />

  Read the article

• 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?

  Read the article

• 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?

  Read the article

• How to specify the cardinality of a @OneToMany in EclipseLink/JPA

  - by simpatico

  I'm trying to impose a @Oneto7 association. I'd have imagined an attribute that specifies the target many value, but have found none. If there is no such attribute, how else, in JPA/EclipseLink would one achieve it?

  Read the article

• 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) { // ... }

  Read the article

• Core Data: Deleting causes 'NSObjectInaccessibleException' from NSOperation with a reference to a deleted object

  - by Bryan Irace

  My application has NSOperation subclasses that fetch and operate on managed objects. My application also periodically purges rows from the database, which can result in the following race condition: An background operation fetches a bunch of objects (from a thread-specific context). It will iterate over these objects and do something with their properties. A bunch of rows are deleted in the main managed object context. The background operation accesses a property on an object that was deleted from the main context. This results in an 'NSObjectInaccessibleException', reason: 'CoreData could not fulfill a fault' Ideally, the objects that are fetched by the NSOperation can be operated on even if one is deleted in the main context. The best way I can think to achieve this is either to: Call [request setReturnsObjectsAsFaults:NO] to ensure that Core Data won't try to fulfill a fault for an object that no longer exists in the main context. The problem here is I may need to access the object's relationships, which (to my understanding) will still be faulted. Iterate through the managed objects up front and copy the properties I will need into separate non-managed objects. The problem here is that (I think) I will need to synchronize/lock this part, in case an object is deleted in the main context before I can finish copying. Am I missing something obvious? It doesn't seem like what I'm trying to accomplish is too out of the ordinary. Thanks for your help.

  Read the article

• 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.

  Read the article

• Rails3: ActiveRecord model relationship with YAML file

  - by moshimoshi

  Hi, I have an ActiveRecord model Group and a YAML table stored in config/users.yaml just like: - {login: titi, password: 123456, group_id: 2} - {login: toto, password: 987654, group_id: 7} And I would like to link them by a sexy way. Can you help me? Many thanks for any help!

  Read the article

• 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() )

  Read the article

• .NET: What is the object header used for?

  - by Jonathan Allen

  In .NET there are 8 bytes of overheard for each object. 4 bytes are a pointer to the object's type. What are the other 4 bytes, known as the object header, used for?

  Read the article

• Dictionary object syntax?

  - by posfan12

  I'm having trouble figuring out the syntax for a JScript .NET dictionary object. I have tried private var myDictionary: Dictionary<string><string>; but the compiler complains that it's missing a semicolon and that the Dictionary object is not declared. I know JScript does have a native dictionary-like object format, but I'm not sure if there are disadvantages to using it instead of the .NET-specific construct. I.e., what if someone wants to extend my script using another .NET language?

  Read the article

• 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

  Read the article

• Joining Tables Based on Foreign Keys

  - by maestrojed

  I have a table that has a lot of fields that are foreign keys referencing a related table. I am writing a script in PHP that will do the db queries. When I query this table for its data I need to know the values associated with these keys not the key. How do most people go about this? A 101 way to do this would be to query this table for its data including the foreign keys and then query the related tables to get each key's value. This could be a lot of queries (~10). Question 1: I think I could write 1 query with a bunch of joins. Would that be better? This approach also requires the querying script to know which table fields are foreign keys. Since I have many tables like this but all with different fields, this means writing nice generic functions is hard. MySQL InnoDB tables allow for foreign constraints. I know the database has these set up correctly. Question 2: What about the idea of querying the table and identifying what the constraints are and then matching them up using whatever process I decide on from Question 1. I like this idea but never see it being used in code. Makes me think its not a good idea for some reason. I would use something like SHOW CREATE TABLE tbl_name; to find what constraints/relationships exist for that table. Thank you for any suggestions or advice.

  Read the article

• 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:

  Read the article

• 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!

  Read the article

• processing json objects in jsp

  - by user98534

  i have a JSON object sent from the browser to the jsp page. how do i receive that object and process it in jsp. do i need any specific parsers? i have used the following piece of code. but it wouldnt work. essentially i should read the contents of the object and print them in the jsp. <%@page language="java" import="jso.JSONObject"%> <% JSONObject inp=request.getParameter("param1"); %> <% for(int i=0;i<inp.size();i++) {%> <%=inp.getString(i)%> <% } %>

  Read the article

• What are the reasons *not* to use a GUID for a primary key?

  - 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?

  Read the article

• How to set up precision attribute used by @Collumn annotation ???

  - by Arthur Ronald F D Garcia

  I often use java.lang.Integer as primary key. Here you can see some piece of code @Entity private class Person { private Integer id; @Id @Column(precision=8, nullable=false) public Integer getId() { } } I need to set up its precision attribute value equal to 8. But, when exporting The schema (Oracle), it does not work as expected. AnnotationConfiguration configuration = new AnnotationConfiguration(); configuration .addAnnotatedClass(Person.class) .setProperty(Environment.DIALECT, "org.hibernate.dialect.OracleDialect") .setProperty(Environment.DRIVER, "oracle.jdbc.driver.OracleDriver"); SchemaExport schema = new SchemaExport(configuration); schema.setOutputFile("schema.sql"); schema.create(true, false); schema.sql outputs create table Person (id number(10,0) not null) Always i get 10. Is There some workaround to get 8 instead of 10 ?

  Read the article

• What is the corrrect way to increment a field making up part of a composit key

  - by Tr1stan

  I have a bunch of tables whose primary key is made up of the foreign keys of other tables (Composite key). Therefore for example the attributes (as a very cut down version) might look like this: A[aPK, SomeFields] 1:M B[bPK, aFK, SomeFields] 1:M C[cPK, bFK, aFK, SomeFields] as data this could look like: A[aPK, SomeFields]: 1, Foo 2, Bar B[bPK, aFK, SomeFields]: 1, 1, FooData1 2, 1, FooData2 1, 2, BarData1 2, 2, BarData2 C[cPK, bFK, aFK, SomeFields]: 1, 1, 1, FooData1More 2, 1, 1, FooData1More 1, 2, 1, FooData2More 2, 2, 1, FooData2More 1, 1, 2, BarData1More 2, 1, 2, BarData1More 1, 2, 2, BarData2More 2, 2, 2, BarData2More I've got this running in a MSSQL DBMS and I'm looking for the best way to increment the left most column, in each table when a new tuple is added to it. I can't use the Auto Increment Identity Specification option as that has no idea that it is part of a composite key. I also don't want to use any aggregate function such as: MAX(field)+1 as this will have adverse affects with multiple users inputting data, rolling back etc. There might however be a nice trigger based option here, but I'm not sure. This must be a common issue so I'm hoping that someone has a lovely solution. As a side which may or may not affect the answer, I'm using Entity Framework 1.0 as my ORM, within a c# MVC application.

  Read the article

< Previous Page | 103 104 105 106 107 108 109 110 111 112 113 114  | Next Page >