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• How to expose an entity via alternate keys with spring data rest

  - by dan carter

  Spring-data-rest does a great job exposing entities via their primary key for GET, PUT and DELETE etc. operations. /myentityies/123 It also exposes search operations. /myentities/search/byMyOtherKey?myOtherKey=123 In my case the entities have a number of alternate keys. The systems calling us, will know the objects by these IDs, rather than our internal primary key. Is it possible to expose the objects via another URL and have the GET, PUT and DELETE handled by the built-in spring-data-rest controllers? /myentities/myotherkey/456 We'd like to avoid forcing the calling systems to have to make two requests for each update. I've tried playing with @RestResource path value, but there doesn't seem to be a way to add additional paths.

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• Data structure supporting the following operations

  - by 500865

  I'm looking for a data structure for working with a set of data which is most efficient to do the following : Check whether an item has been categorized or not. (The categorized and uncategorized set are disjoint sets). Get the category of an item. Get all the items in a particular category. Get all the uncategorized items. Remove a particular item from the data set. I was thinking of having a Dictionary<String, Set<String>> to hold all the items in a given category, but that doesn't solve 2.

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• Delphi Exception Handling - How to clean up properly?

  - by Tom

  I'm looking at some code in an application of ours and came across something a little odd from what I normally do. With exception handling and cleanup, we (as well as many other programmers out there, I'm sure) use a Try/Finally block embedded with a Try/Except block. Now I'm used to the Try/Except inside the Try/Finally like so: Try Try CouldCauseError(X); Except HandleError; end; Finally FreeAndNil(x); end; but this other block of code is reversed as so: Try Try CouldCauseError(X); Finally FreeAndNil(x); end; Except HandleError; end; Looking around the web, I'm seeing folks doing this both ways, with no explanation as to why. My question is, does it matter which gets the outside block and which gets the inside block? Or will the except and finally sections get handled no matter which way it is structured? Thanks.

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• Error Handling in T-SQL Scalar Function

  - by hydroparadise

  Ok.. this question could easily take multiple paths, so I will hit the more specific path first. While working with SQL Server 2005, I'm trying to create a scalar funtion that acts as a 'TryCast' from varchar to int. Where I encounter a problem is when I add a TRY block in the function; CREATE FUNCTION u_TryCastInt ( @Value as VARCHAR(MAX) ) RETURNS Int AS BEGIN DECLARE @Output AS Int BEGIN TRY SET @Output = CONVERT(Int, @Value) END TRY BEGIN CATCH SET @Output = 0 END CATCH RETURN @Output END Turns out theres all sorts of things wrong with this statement including "Invalid use of side-effecting or time-dependent operator in 'BEGIN TRY' within a function" and "Invalid use of side-effecting or time-dependent operator in 'END TRY' within a function". I can't seem to find any examples of using try statements within a scalar function, which got me thinking, is error handling in a function is possible? The goal here is to make a robust version of the Convert or Cast functions to allow a SELECT statement carry through depsite conversion errors. For example, take the following; CREATE TABLE tblTest ( f1 VARCHAR(50) ) GO INSERT INTO tblTest(f1) VALUES('1') INSERT INTO tblTest(f1) VALUES('2') INSERT INTO tblTest(f1) VALUES('3') INSERT INTO tblTest(f1) VALUES('f') INSERT INTO tblTest(f1) VALUES('5') INSERT INTO tblTest(f1) VALUES('1.1') SELECT CONVERT(int,f1) AS f1_num FROM tblTest DROP TABLE tblTest It never reaches point of dropping the table because the execution gets hung on trying to convert 'f' to an integer. I want to be able to do something like this; SELECT u_TryCastInt(f1) AS f1_num FROM tblTest fi_num __________ 1 2 3 0 5 0 Any thoughts on this? Is there anything that exists that handles this? Also, I would like to try and expand the conversation to support SQL Server 2000 since Try blocks are not an option in that scenario. Thanks in advance.

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• C# - WinForms - Exception Handling for Events

  - by JustLooking

  Hi all, I apologize if this is a simple question (my Google-Fu may be bad today). Imagine this WinForms application, that has this type of design: Main application - shows one dialog - that 1st dialog can show another dialog. Both of the dialogs have OK/Cancel buttons (data entry). I'm trying to figure out some type of global exception handling, along the lines of Application.ThreadException. What I mean is: Each of the dialogs will have a few event handlers. The 2nd dialog may have: private void ComboBox_SelectedIndexChanged(object sender, EventArgs e) { try { AllSelectedIndexChangedCodeInThisFunction(); } catch(Exception ex) { btnOK.enabled = false; // Bad things, let's not let them save // log stuff, and other good things } } Really, all the event handlers in this dialog should be handled in this way. It's an exceptional-case, so I just want to log all the pertinent information, show a message, and disable the okay button for that dialog. But, I want to avoid a try/catch in each event handler (if I could). A draw-back of all these try/catch's is this: private void someFunction() { // If an exception occurs in SelectedIndexChanged, // it doesn't propagate to this function combobox.selectedIndex = 3; } I don't believe that Application.ThreadException is a solution, because I don't want the exception to fall all the way-back to the 1st dialog and then the main app. I don't want to close the app down, I just want to log it, display a message, and let them cancel out of the dialog. They can decide what to do from there (maybe go somewhere else in the app). Basically, a "global handler" in between the 1st dialog and the 2nd (and then, I suppose, another "global handler" in between the main app and the 1st dialog). Thanks.

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• Help with Exception Handling in ASP.NET C# Application

  - by Shrewd Demon

  hi, yesterday i posted a question regarding the Exception Handling technique, but i did'nt quite get a precise answer, partly because my question must not have been precise. So i will ask it more precisely. There is a method in my BLL for authenticating user. If a user is authenticated it returns me the instance of the User class which i store in the session object for further references. the method looks something like this... public static UsersEnt LoadUserInfo(string email) { SqlDataReader reader = null; UsersEnt user = null; using (ConnectionManager cm = new ConnectionManager()) { SqlParameter[] parameters = new SqlParameter[1]; parameters[0] = new SqlParameter("@Email", email); try { reader = SQLHelper.ExecuteReader(cm.Connection, "sp_LoadUserInfo", parameters); } catch (SqlException ex) { //this gives me a error object } if (reader.Read()) user = new UsersDF(reader); } return user; } now my problem is suppose if the SP does not exist, then it will throw me an error or any other SQLException for that matter. Since this method is being called from my aspx.cs page i want to return some meaning full message as to what could have gone wrong so that the user understands that there was some problem and that he/she should retry logging-in again. but i can't because the method returns an instance of the User class, so how can i return a message instead ?? i hope i made it clear ! thank you.

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• Exception Handling in ASP.NET MVC and Ajax - [HandleException] filter

  - by Graham

  All, I'm learning MVC and using it for a business app (MVC 1.0). I'm really struggling to get my head around exception handling. I've spent a lot of time on the web but not found anything along the lines of what I'm after. We currently use a filter attribute that implements IExceptionFilter. We decorate a base controller class with this so all server side exceptions are nicely routed to an exception page that displays the error and performs logging. I've started to use AJAX calls that return JSON data but when the server side implementation throws an error, the filter is fired but the page does not redirect to the Error page - it just stays on the page that called the AJAX method. Is there any way to force the redirect on the server (e.g. a ASP.NET Server.Transfer or redirect?) I've read that I must return a JSON object (wrapping the .NET Exception) and then redirect on the client, but then I can't guarantee the client will redirect... but then (although I'm probably doing something wrong) the server attempts to redirect but then gets an unauthorised exception (the base controller is secured but the Exception controller is not as it does not inherit from this) Has anybody please got a simple example (.NET and jQuery code). I feel like I'm randomly trying things in the hope it will work Exception Filter so far... public class HandleExceptionAttribute : FilterAttribute, IExceptionFilter { #region IExceptionFilter Members public void OnException(ExceptionContext filterContext) { if (filterContext.ExceptionHandled) { return; } filterContext.Controller.TempData[CommonLookup.ExceptionObject] = filterContext.Exception; if (filterContext.HttpContext.Request.IsAjaxRequest()) { filterContext.Result = AjaxException(filterContext.Exception.Message, filterContext); } else { //Redirect to global handler filterContext.Result = new RedirectToRouteResult(new RouteValueDictionary(new { controller = AvailableControllers.Exception, action = AvailableActions.HandleException })); filterContext.ExceptionHandled = true; filterContext.HttpContext.Response.Clear(); } } #endregion private JsonResult AjaxException(string message, ExceptionContext filterContext) { if (string.IsNullOrEmpty(message)) { message = "Server error"; //TODO: Replace with better message } filterContext.HttpContext.Response.StatusCode = (int)HttpStatusCode.InternalServerError; filterContext.HttpContext.Response.TrySkipIisCustomErrors = true; //Needed for IIS7.0 return new JsonResult { Data = new { ErrorMessage = message }, ContentEncoding = Encoding.UTF8, }; } }

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• VB .NET error handling, pass error to caller

  - by user1375452

  this is my very first project on vb.net and i am now struggling to migrate a vba working add in to a vb.net COM Add-in. I think i'm sort of getting the hang, but error handling has me stymied. This is a test i've been using to understand the try-catch and how to pass exception to caller Public Sub test() Dim ActWkSh As Excel.Worksheet Dim ActRng As Excel.Range Dim ActCll As Excel.Range Dim sVar01 As String Dim iVar01 As Integer Dim sVar02 As String Dim iVar02 As Integer Dim objVar01 As Object ActWkSh = Me.Application.ActiveSheet ActRng = Me.Application.Selection ActCll = Me.Application.ActiveCell iVar01 = iVar02 = 1 sVar01 = CStr(ActCll.Value) sVar02 = CStr(ActCll.Offset(1, 0).Value) Try objVar01 = GetValuesV(sVar01, sVar02) 'DO SOMETHING HERE Catch ex As Exception MsgBox("ERRORE: " + ex.Message) 'LOG ERROR SOMEWHERE Finally MsgBox("DONE!") End Try End Sub Private Function GetValuesV(ByVal QryStr As Object, ByVal qryConn As String) As Object Dim cnn As Object Dim rs As Object Try cnn = CreateObject("ADODB.Connection") cnn.Open(qryConn) rs = CreateObject("ADODB.recordset") rs = cnn.Execute(QryStr) If rs.EOF = False Then GetValuesV = rs.GetRows Else Throw New System.Exception("Query Return Empty Set") End If Catch ex As Exception Throw ex Finally rs.Close() cnn.Close() End Try End Function i'd like to have the error message up to test, but MsgBox("ERRORE: " + ex.Message) pops out something unexpected (Object variable or With block variable not set) What am i doing wrong here?? Thanks D

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• Error handling approach on PHP

  - by Industrial

  Hi everybody, We have a web server that we're about to launch a number of applications onto. They will all share database and memcached servers, but each application has it's own mySQL database and all memcached keys per application, is prefixed. Possible scenario: If a memcached server in our cluster goes boom, we want someone (operative system admin) to be automatically contacted by email/iphone push notification or in any other appropriate way. If we we're about to install 150 identical applications for our customers on our servers, and a memcached server dies - all 150 applications will individually find this out and contact our system admin, which most certainly is going to think about getting a new job where he or she isn't about to be woken up by getting 150 messages sent 4:15 in the morning. Possible solution: One idea is to set up an external server for error handling that gets a $_POST or cURL request sent, and handles storage of the error message depending on the seriousness of the actual error message. It would of course check upon receiving the error call, that if the same memcached server have already been reported as offline, there would be no need to spam the system admin with additional reminders... The questions: What's a good approach on how to handle errors? How does the big guys in the industry handle this? Thanks!

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• Error monitoring/handling on webservers

  - by Industrial

  Hi everybody, We have a web server that we're about to launch a number of applications onto. They will all share database and memcached servers, but each application has it's own mySQL database and all memcached keys per application, is prefixed. Possible scenario: If a memcached server in our cluster goes boom, we want someone (operative system admin) to be automatically contacted by email/iphone push notification or in any other appropriate way. If we we're about to install 150 identical applications for our customers on our servers, and a memcached server dies - all 150 applications will individually find this out and contact our system admin, which most certainly is going to think about getting a new job where he or she isn't about to be woken up by getting 150 messages sent 4:15 in the morning. Possible solution: One idea is to set up an external server for error handling that gets a $_POST or cURL request sent, and handles storage of the error message depending on the seriousness of the actual error message. It would of course check upon receiving the error call, that if the same memcached server have already been reported as offline, there would be no need to spam the system admin with additional reminders... The questions: What's a good approach on how to handle errors? How does the big guys in the industry handle this? Thanks!

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• UPOS RFIDScanner data format

  - by Robert Snyder

  A lot of work that I do currently is based in the OPOS/UPOS world. My company has a device that can read 13.56Mhz tags (RFID), Smart Cards, and Mag Stripe cards. Up until somewhat recently I have only been working with RFID for a very specific scenario. That was to read UltraLight C and Desfire cards. These cards were all setup very specifically so that I could take the data read from those cards and force it into a MSR track2 format. The past couple of weeks, however, I have been working on reading RFID credit cards (since I have a Visa card I've been using mine), and Smart Card credit cards. (The visa card I have has both) In learning how to communicate with SmartCard and reading ISO7816 and EMVCO documents I became a little more familiar with how info is stored. But now I have a question regarding UPOS. The RFID data on my Visa is stored (and read) very similar to how the data is stored and read from the Smart Card on my Visa. Cool. Well in the UPOS spec for SmartCardRW the ReadData method returns a byte array. That's cool, I can just return all that data and then parse it as my heart desires. The RFID though has a LinkedList of Tags. Well this makes sense in terms of my Visa card (reminds me of a question I have in regards to SmartCard, but that is for another question) but what about ULC and Desfire, or for that matter any Mifare card. Pages, Files, Purses don't exactly fit the Tag profile. For instance lets just say I read pages 4-12 on my ULC card. Each page I read is 4 bytes long. Does this mean I have 9 tags in my LinkedList? Is my Tag id the page number? Or then how does that translate to Desfire? I open application 123456 and read file 1 and file 2, Do I have 2 tags? and if so what is my tag id? At least with my Visa I think that I have to use the Tag id (ex 5F24 for my expiration date) and value of {0x15, 0x10, 0x31} Part of me says yes..that makes sense. Another part of me says, "well if that is the case then why doesn't SmartCardRW have Tags?" So that is my question. How do I format my data from those different types of media? or is that the job of my Control Object (the application)? Is so how does it know? The only protocols I have are: // Summary: // Enumerates the available predefined RFID tag protocols the device supports. [Flags] public enum RFIDProtocols { EpcClass0 = 1, RFIDSdt0Plus = 2, EpcClass1 = 4, EpcClass1Gen2 = 8, EpcClass2 = 16, Iso14443A = 4096, Iso14443B = 8192, Iso15693 = 12288, Iso180006B = 16384, Other = 16777216, All = 1073741824, } If I use that well all of my cards that I have are all Iso14443A. I use the ATQA and the SAK to know what type of card I really have. There is no RFID property that lets me specify that. So I'm lost.

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• Integrating WIF with WCF Data Services

  - by cibrax

  A time ago I discussed how a custom REST Starter kit interceptor could be used to parse a SAML token in the Http Authorization header and wrap that into a ClaimsPrincipal that the WCF services could use. The thing is that code was initially created for Geneva framework, so it got deprecated quickly. I recently needed that piece of code for one of projects where I am currently working on so I decided to update it for WIF. As this interceptor can be injected in any host for WCF REST services, also represents an excellent solution for integrating claim-based security into WCF Data Services (previously known as ADO.NET Data Services). The interceptor basically expects a SAML token in the Authorization header. If a token is found, it is parsed and a new ClaimsPrincipal is initialized and injected in the WCF authorization context. public class SamlAuthenticationInterceptor : RequestInterceptor {   SecurityTokenHandlerCollection handlers;   public SamlAuthenticationInterceptor()     : base(false)   {     this.handlers = FederatedAuthentication.ServiceConfiguration.SecurityTokenHandlers;   }   public override void ProcessRequest(ref RequestContext requestContext)   {     SecurityToken token = ExtractCredentials(requestContext.RequestMessage);     if (token != null)     {       ClaimsIdentityCollection claims = handlers.ValidateToken(token);       var principal = new ClaimsPrincipal(claims);       InitializeSecurityContext(requestContext.RequestMessage, principal);     }     else     {       DenyAccess(ref requestContext);     }   }   private void DenyAccess(ref RequestContext requestContext)   {     Message reply = Message.CreateMessage(MessageVersion.None, null);     HttpResponseMessageProperty responseProperty = new HttpResponseMessageProperty() { StatusCode = HttpStatusCode.Unauthorized };     responseProperty.Headers.Add("WWW-Authenticate",           String.Format("Basic realm=\"{0}\"", ""));     reply.Properties[HttpResponseMessageProperty.Name] = responseProperty;     requestContext.Reply(reply);     requestContext = null;   }   private SecurityToken ExtractCredentials(Message requestMessage)   {     HttpRequestMessageProperty request = (HttpRequestMessageProperty)  requestMessage.Properties[HttpRequestMessageProperty.Name];     string authHeader = request.Headers["Authorization"];     if (authHeader != null && authHeader.Contains("<saml"))     {       XmlTextReader xmlReader = new XmlTextReader(new StringReader(authHeader));       var col = SecurityTokenHandlerCollection.CreateDefaultSecurityTokenHandlerCollection();       SecurityToken token = col.ReadToken(xmlReader);                                        return token;     }     return null;   }   private void InitializeSecurityContext(Message request, IPrincipal principal)   {     List<IAuthorizationPolicy> policies = new List<IAuthorizationPolicy>();     policies.Add(new PrincipalAuthorizationPolicy(principal));     ServiceSecurityContext securityContext = new ServiceSecurityContext(policies.AsReadOnly());     if (request.Properties.Security != null)     {       request.Properties.Security.ServiceSecurityContext = securityContext;     }     else     {       request.Properties.Security = new SecurityMessageProperty() { ServiceSecurityContext = securityContext };      }    }    class PrincipalAuthorizationPolicy : IAuthorizationPolicy    {      string id = Guid.NewGuid().ToString();      IPrincipal user;      public PrincipalAuthorizationPolicy(IPrincipal user)      {        this.user = user;      }      public ClaimSet Issuer      {        get { return ClaimSet.System; }      }      public string Id      {        get { return this.id; }      }      public bool Evaluate(EvaluationContext evaluationContext, ref object state)      {        evaluationContext.AddClaimSet(this, new DefaultClaimSet(System.IdentityModel.Claims.Claim.CreateNameClaim(user.Identity.Name)));        evaluationContext.Properties["Identities"] = new List<IIdentity>(new IIdentity[] { user.Identity });        evaluationContext.Properties["Principal"] = user;        return true;      }    } A WCF Data Service, as any other WCF Service, contains a service host where this interceptor can be injected. The following code illustrates how that can be done in the “svc” file. <%@ ServiceHost Language="C#" Debug="true" Service="ContactsDataService"                 Factory="AppServiceHostFactory" %> using System; using System.ServiceModel; using System.ServiceModel.Activation; using Microsoft.ServiceModel.Web; class AppServiceHostFactory : ServiceHostFactory {    protected override ServiceHost CreateServiceHost(Type serviceType, Uri[] baseAddresses)   {     WebServiceHost2 result = new WebServiceHost2(serviceType, true, baseAddresses);     result.Interceptors.Add(new SamlAuthenticationInterceptor());                 return result;   } } WCF Data Services includes an specific WCF host of out the box (DataServiceHost). However, the service is not affected at all if you replace it with a custom one as I am doing in the code above (WebServiceHost2 is part of the REST Starter kit). Finally, the client application needs to pass the SAML token somehow to the data service. In case you are using any Http client library for consuming the data service, that’s easy to do, you only need to include the SAML token as part of the “Authorization” header. If you are using the auto-generated data service proxy, a little piece of code is needed to inject a SAML token into the DataServiceContext instance. That class provides an event “SendingRequest” that any client application can leverage to include custom code that modified the Http request before it is sent to the service. So, you can easily create an extension method for the DataServiceContext that negotiates the SAML token with an existing STS, and adds that token as part of the “Authorization” header. public static class DataServiceContextExtensions {        public static void ConfigureFederatedCredentials(this DataServiceContext context, string baseStsAddress, string realm)   {     string address = string.Format(STSAddressFormat, baseStsAddress, realm);                  string token = NegotiateSecurityToken(address);     context.SendingRequest += (source, args) =>     {       args.RequestHeaders.Add("Authorization", token);     };   } private string NegotiateSecurityToken(string address) { } } I left the NegociateSecurityToken method empty for this extension as it depends pretty much on how you are negotiating tokens from an existing STS. In case you want to end-to-end REST solution that involves an Http endpoint for the STS, you should definitely take a look at the Thinktecture starter STS project in codeplex.

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• How to disable authentication schemes for WCF Data Services

  - by Schneider

  When I deployed my WCF Data Services to production hosting I started to get the following error (or similar depending on which auth schemes are active): IIS specified authentication schemes 'Basic, Anonymous', but the binding only supports specification of exactly one authentication scheme. Valid authentication schemes are Digest, Negotiate, NTLM, Basic, or Anonymous. Change the IIS settings so that only a single authentication scheme is used. Apparently WCF Data Services (WCF in general?) cannot handle having more than once authentication scheme active. OK so I am aware that I can disable all-but-one authentication scheme on the web application via IIS control panel .... via a support request!! Is there a way to specify a single authentication scheme on a per-service level in the web.config? I thought this might be as straight forward as making a change to <system.serviceModel> but... it turns out that WCF Data Services do not configure themselves in the web config. If you look at the DataService<> class it does not implement a [ServiceContract] hence you cannot refer to it in the <service><endpoint>...which I presume would be needed for changing its configuration via XML. P.S. Our host is using II6, but both solutions for IIS6 & IIS7 appreciated.

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• Handling multiple column data with Java

  - by Ender

  I am writing an application that reads in a large number of basic user details in the following format; once read in it then allows the user to search for a user's details using their email: NAME ROLE EMAIL --------------------------------------------------- Joe Bloggs Manager [email protected] John Smith Consultant [email protected] Alan Wright Tester [email protected] ... The problem I am suffering is that I need to store a large number of details of all people that have worked at the company. The file containing these details will be written on a yearly basis simply for reporting purposes, but the program will need to be able to access these details quickly. The way I aim to access these files is to have a program that asks the user for the name of the unique email of the member of staff and for the program to then return the name and the role from that line of the file. I've played around with text files, but am struggling with how I would handle multiple columns of data when it comes to searching this large file. What is the best format to store such data in? A text file? XML? The size doesn't bother me, but I'd like to be able to search it as quickly as possible. The file will need to contain a lot of entries, probably over the 10K mark over time.

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• Correctly assigning value to a Core Data attribute with an integer data-type

  - by Gordon Fontenot

  I'm missing something here, and feeling like an idiot about it. I'm using a UIPickerView in my app, and I need to assign the row number to a 32-bit integer attribute for a Core Data object. To do this, I am using this method: -(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component { object.integerValue = row; } This is giving me a warning: warning: passing argument 1 of 'setIntegerValue:' makes pointer from integer without a cast What am I mixing up here? --Edit 1-- Ok, so I can get rid of the warning by changing the method to do the following: NSNumber *number = [NSNumber numberWithInteger:row]; object.integerValue = rating; However, I still get a value of 0 for object.integerValue if I use NSLog to print it out. object.integerValue has a max value of 5, so I print out number instead, and then I'm getting a number above 62,000,000. Which doesn't seem right to me, since there are 5 rows. If I NSLog the row variable, I get a number between 0 and 5. So why do I end up with a completely different number after casting the number to NSNumber? --Edit 2-- Ok, so I'm realizing that there is some fundamental idea that I don't understand. I now understand that the 60 million + number can be cast back to the correct 0-5 number by using integerValue. So, it seems my question is how can I save an integer between 0-5 to the attribute if the NSNumber that is returned is over 60 million? Do I need to be using a different data type?

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• Doubts About Core Data NSManagedObject Deep Copy

  - by Jigzat

  Hello everyone, I have a situation where I must copy one NSManagedObject from the main context into an editing context. It sounds unnecessary to most people as I have seen in similar situations described in Stackoverflow but I looks like I need it. In my app there are many views in a tab bar and every view handles different information that is related to the other views. I think I need multiple MOCs since the user may jump from tab to tab and leave unsaved changes in some tab but maybe it saves data in some other tab/view so if that happens the changes in the rest of the views are saved without user consent and in the worst case scenario makes the app crash. For adding new information I got away by using an adding MOC and then merging changes in both MOCs but for editing is not that easy. I saw a similar situation here in Stackoverflow but the app crashes since my data model doesn't seem to use NSMutableSet for the relationships (I don't think I have a many-to-many relationship, just one-to-many) I think it can be modified so I can retrieve the relationships as if they were attributes for (NSString *attr in relationships) { [cloned setValue:[source valueForKey:attr] forKey:attr]; } but I don't know how to merge the changes of the cloned and original objects. I think I could just delete the object from the main context, then merge both contexts and save changes in the main context but I don't know if is the right way to do it. I'm also concerned about database integrity since I'm not sure that the inverse relationships will keep the same reference to the cloned object as if it were the original one. Can some one please enlighten me about this?

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• Binding Data to a TextBlock using Domain Data Source

  - by TFisher

  I have a map with hotspots for each state (done in Expression Blend). I capture each MouseEnter of the state (1 thru 50). I pass that into my Domain Data Source: Dim activebox As Path = TryCast(sender, Path) activebox.Fill = mouseOverColor Dim StateID As Integer = CInt(Right(activebox.Name, 2)) Dim _StateContext As New StateContext myDataGrid.ItemsSource = _StateContext.States _StateContext.Load(_StateContext.GetStateByStateIDQuery(StateID.Text)) The above works fine for a datagrid, listbox and even a dataform. But I created a popup with a stackpanel that has textblocks. popupStatesBox.DataContext = ?????????????? popupStatesBox.IsOpen = True 'popup does open but has no data -- popupStatesBox.xaml <Popup x:Name="popupStatsBox" Margin="8,35,0,8" DataContext="{Binding}" IsOpen="false" Width="268" HorizontalAlignment="Left"> <StackPanel x:Name="Layout" Background="Black"> <TextBlock x:Name="tbState" Text="{Binding StateName /> <TextBlock x:Name="tbAbbrev" Text="{Binding Abbreviation}" /> </StackPanel> </Popup> How do I get the textblocks to display the values from the _StateContext. StackPanel has DataContext but no ItemsSource. What am I missing?

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• Design suggestion for expression tree evaluation with time-series data

  - by Lirik

  I have a (C#) genetic program that uses financial time-series data and it's currently working but I want to re-design the architecture to be more robust. My main goals are: sequentially present the time-series data to the expression trees. allow expression trees to access previous data rows when needed. to optimize performance of the data access while evaluating the expression trees. keep a common interface so various types of data can be used. Here are the possible approaches I've thought about: I can evaluate the expression tree by passing in a data row into the root node and let each child node use the same data row. I can evaluate the expression tree by passing in the data row index and letting each node get the data row from a shared DataSet (currently I'm passing the row index and going to multiple synchronized arrays to get the data). Hybrid: an immutable data set is accessible by all of the expression trees and each expression tree is evaluated by passing in a data row. The benefit of the first approach is that the data row is being passed into the expression tree and there is no further query done on the data set (which should increase performance in a multithreaded environment). The drawback is that the expression tree does not have access to the rest of the data (in case some of the functions need to do calculations using previous data rows). The benefit of the second approach is that the expression trees can access any data up to the latest data row, but unless I specify what that row is, I'll have to iterate through the rows and figure out which one is the last one. The benefit of the hybrid is that it should generally perform better and still provide access to the earlier data. It supports two basic "views" of data: the latest row and the previous rows. Do you guys know of any design patterns or do you have any tips that can help me build this type of system? Should I use a DataSet to hold and present the data, or are there more efficient ways to present rows of data while maintaining a simple interface? FYI: All of my code is written in C#.

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• Is this WPF error handling a good idea ?

  - by Adiel

  I have a multi threaded wpf application with various HW interfaces. I want to react to several HW failures that can happen. For example : one of the interfaces is a temperature sensor and i want that from a certain temp. a meesage would appear and notify the user that it happened. i came up with the follwing design : /// <summary> /// This logic reacts to errors that occur during the system run. /// The reaction is set by the component that raised the error. /// </summary> public class ErrorHandlingLogic : Logic { } the above class would consume ErrorEventData that holds all the information about the error that occurred. public class ErrorEventData : IEventData { #region public enum public enum ErrorReaction { } #endregion public enum #region Private Data Memebers and props private ErrorReaction m_ErrorReaction; public ErrorReaction ErrorReactionValue { get { return m_ErrorReaction; } set { m_ErrorReaction = value; } } private string m_Msg; public string Msg { get { return m_Msg; } set { m_Msg = value; } } private string m_ComponentName; public string ComponentName { get { return m_ComponentName; } set { m_ComponentName = value; } } #endregion Private Data Memebers and props public ErrorEventData(ErrorReaction reaction, string msg, string componenetName) { m_ErrorReaction = reaction; m_Msg = msg; m_ComponentName = componenetName; } } the above ErrorHandlingLogic would decide what to do with the ErrorEventData sent to him from various components of the application. if needed it would be forwarded to the GUI to display a message to the user. so what do you think is it a good design ? thanks, Adiel.

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• Data Warehouse: Modelling a future schedule

  - by Pat

  I'm creating a DW that will contain data on financial securities such as bonds and loans. These securities are associated with payment schedules. For example, a bond could pay quarterly, while a mortage would usually pay monthly (sometimes biweekly). The payment schedule is created when the security is traded and, in the majority of cases, will remain unchanged. However, the design would need to accomodate those cases where it does change. I'm currently attempting to model this data and I'm having difficulty coming up with a workable design. One of the most commonly queried fields is "next payment date". Users often want to know when a security will pay next. Therefore, I want to make it as easy as possible for them to get the next payment date and amount for each security. Also, users often run historical queries in which case they'd want the next payment date and amount as of a specific point in time. For example, they may want to look back at 1/31/09 and query the next payment dates (which would usually be in February 2009 for mortgages). It's also common that they want to query a security's entire payment schedule, which might consist of 360 records (30 year mortgage x 12 payments/year). Since the next payment date and amount would be changing each month or even biweekly, these fields wouldn't seem to fit into a slow-changing dimension very well. It would probably make more sense to use a fact table, but I'm unsure of how to model it. Any ideas would be greatly appreciated.

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• How to represent a Rubik's Cube in a data structure

  - by Mel

  I am just curious, how will you guys create a data structure for a rubik's cube with X number of sides. Things to consider: - the cube can be of any size - it is a rubik's cube! so layers can be rotated (in all three axes) and a plus question: using the data structure, how can we know if a certain cube in a certain state is solvable? I have been struggling with this question my self and haven't quite found the answer yet.

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• SQL SERVER – What is MDS? – Master Data Services in Microsoft SQL Server 2008 R2

  - by pinaldave

  What is MDS? Master Data Services helps enterprises standardize the data people rely on to make critical business decisions. With Master Data Services, IT organizations can centrally manage critical data assets company wide and across diverse systems, enable more people to securely manage master data directly, and ensure the integrity of information over time. (Source: Microsoft) Today I will be talking about the same subject at Microsoft TechEd India. If you want to learn about how to standardize your data and apply the business rules to validate data you must attend my session. MDS is very interesting concept, I will cover super short but very interesting 10 quick slides about this subject. I will make sure in very first 20 mins, you will understand following topics Introduction to Master Data Management What is Master Data and Challenges MDM Challenges and Advantage Microsoft Master Data Services Benefits and Key Features Uses of MDS Capabilities Key Features of MDS This slides decks will be followed by around 30 mins demo which will have story of entity, hierarchies, versions, security, consolidation and collection. I will be tell this story keeping business rules in center. We take one business rule which will be simple validation rule and will make it much more complex and yet very useful to product. I will also demonstrate few real life scenario where I will be talking about MDS and its usage. Do not miss this session. At the end of session there will be book awarded to best participant. My session details: Session: Master Data Services in Microsoft SQL Server 2008 R2 Date: April 12, 2010  Time: 2:30pm-3:30pm SQL Server Master Data Services will ship with SQL Server 2008 R2 and will improve Microsoft’s platform appeal. This session provides an in depth demonstration of MDS features and highlights important usage scenarios. Master Data Services enables consistent decision making by allowing you to create, manage and propagate changes from single master view of your business entities. Also with MDS – Master Data-hub which is the vital component helps ensure reporting consistency across systems and deliver faster more accurate results across the enterprise. We will talk about establishing the basis for a centralized approach to defining, deploying, and managing master data in the enterprise. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Business Intelligence, Data Warehousing, MVP, Pinal Dave, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Author Visit, T SQL, Technology Tagged: TechEd, TechEdIn

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• SQLAuthority News – SQL Server Technical Article – The Data Loading Performance Guide

  - by pinaldave

  The white paper describes load strategies for achieving high-speed data modifications of a Microsoft SQL Server database. “Bulk Load Methods” and “Other Minimally Logged and Metadata Operations” provide an overview of two key and interrelated concepts for high-speed data loading: bulk loading and metadata operations. After this background knowledge, white paper describe how these methods can be [...]

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• Data caching in ASP.Net applications

  - by nikolaosk

  In this post I will continue my series of posts on caching. You can read my other post in Output caching here .You can read on how to cache a page depending on the user's browser language. Output caching has its place as a caching mechanism. But right now I will focus on data caching .The advantages of data caching are well known but I will highlight the main points. We have improvements in response times We have reduced database round trips We have different levels of caching and it is up to us...(read more)

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• SQL Developer Data Modeler: On Notes, Comments, and Comments in RDBMS

  - by thatjeffsmith

  Ah the beautiful data model. They say a picture is worth a 1,000 words. And then we have our diagrams, how many words are they worth? Our friends from the Human Relations sample schema So our models describe how the data ‘works’ – whether that be at a logical-business level, or a technical-physical level. Developers like to say that their code is self-documenting. These would be very lazy or very bad (or both) developers. Models are the same way, you should document your models with comments and notes! I have 3 basic options: Comments Comments in RDBMS Notes So what’s the difference? Comments You’re describing the entity/table or attribute/column. This information will NOT be published in the database. It will only be available to the model, and hence, folks with access to the model. Table Comments (in the design only!) Comments in RDBMS You’re doing the same thing as above, but your words will be stored IN the data dictionary of the database. Oracle allows you to store comments on the table and column definitions. So your awesome documentation is going to be viewable to anyone with access to the database. RDBMS is an acronym for Relational Database Management System – of which Oracle is one of the first commercial examples If the DDL is produced and ran against a database, these comments WILL be stored in the data dictionary. Notes A place for you to add notes, maybe from a design meeting. Or maybe you’re using this as a to-do or requirements list. Basically it’s for anything that doesn’t literally describe the object at hand – that’s what the comments are for. I totally made these up. Now these are free text fields and you can put whatever you want here. Just make sure you put stuff here that’s worth reading. And it will live on…forever.

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