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unexpected error in C# asp.net - conversion error

Posted on 2010-08-19
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Last Modified: 2013-12-17

Hi group,

I'm having a question about a situation I have run into .... on one hand I have a pre-written code in C# and on other hand it talks to an old database (DB2). I'm asked to fix it!
now, I have the error message and finally after hours asking here and there I was able to get access to a machine to see the code.

The funny part is that code works but sometimes it throws the error in following. At the same time I noticed this error happens (NOT SURE 100%) when few people working on database (directly).

Can somebody tell me by looking at code  what is causing this? I understand there is a conversion error. Also, I was told that DBA has changed new field into table so the order of fields is changed.

I'm not sure if order matters. any idea?

Thanks,
ak



A conversion error occurred.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.



Exception Details: IBM.Data.DB2.iSeries.iDB2ConversionException: A conversion error occurred.



Source Error:



An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.



Stack Trace:



[iDB2ConversionException: A conversion error occurred.]

   AppCenter.Models.UserRepository.Get(String key) in C:\Projects\AppCenter\AppCenter\Models\UserRepository.cs:148

   AppCenter.Controllers.AccountController.Login(String userName, String password, Boolean rememberMe, String returnUrl) in C:\Projects\AppCenter\AppCenter\Controllers\AccountController.cs:80

   lambda_method(ExecutionScope , ControllerBase , Object[] ) +245

   System.Web.Mvc.ActionMethodDispatcher.Execute(ControllerBase controller, Object[] parameters) +17

   System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters) +178

   System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters) +24

   System.Web.Mvc.<>c__DisplayClassa.<InvokeActionMethodWithFilters>b__7() +52

   System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter filter, ActionExecutingContext preContext, Func`1 continuation) +254

   System.Web.Mvc.<>c__DisplayClassc.<InvokeActionMethodWithFilters>b__9() +19

   System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodWithFilters(ControllerContext controllerContext, IList`1 filters, ActionDescriptor actionDescriptor, IDictionary`2 parameters) +192

   System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext, String actionName) +399

   System.Web.Mvc.Controller.ExecuteCore() +126

   System.Web.Mvc.ControllerBase.Execute(RequestContext requestContext) +27

   System.Web.Mvc.ControllerBase.System.Web.Mvc.IController.Execute(RequestContext requestContext) +7

   System.Web.Mvc.MvcHandler.ProcessRequest(HttpContextBase httpContext) +151

   System.Web.Mvc.MvcHandler.ProcessRequest(HttpContext httpContext) +57

   System.Web.Mvc.MvcHandler.System.Web.IHttpHandler.ProcessRequest(HttpContext httpContext) +7

   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +181

   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +75

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Question by:akohan
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Expert Comment

by:gmarino
Comment Utility
You don't give much to work with. There is not enough information in the error to diagnose the problem.

"DBA has changed new field into table so the order of fields is changed."  <<-- This could pose a problem IF the C# code uses SELECT *  instead of listing out the specific column names.  Check the code for SELECT * FROM.

- Greg
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Author Comment

by:akohan
Comment Utility

Hi Greg,

I will look at it further, it is just I was given the task today. it is like asking you to fix a bug when you have no idea yet what the code is doing or even where it is located

Sure but you are right I saw few queries with * rather than specifing fields name. Things like:  SELECT  *  FROM tbl_xyz and ....

thanks,
ak
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Assisted Solution

by:raja_ind82
raja_ind82 earned 100 total points
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Expert Comment

by:momi_sabag
Comment Utility
since it sometime work and sometimes not, this is a data error
i guess you have some issue with the dates format in your input
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Author Comment

by:akohan
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Gmarino,

Are you saying I have to change * to fields one by one in SELECT statements? if so, then why * causing the issue?

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Accepted Solution

by:
gmarino earned 150 total points
Comment Utility
ak,

I'm not saying it IS causing the issue.  Rather I am just fishing for possible problems.

You stated "that DBA has changed new field into table so the order of fields is changed."

When using SELECT * FROM table, the columns are presented in the order they exist in the table.  If someone changes the order of the columns in the table AND (here's the key) you are binding those columns to variables or an array in the C# code, then Column_C which used to be bound to Variable_C could now be bound to a different variable.

Old Table Layout
Column_A
Column_B
Column_C

Select *...into Var_A,Var_B,Var_C  returns
Var_A=Column_A
Var_B=Column_B
Var_C=Column_C


New Table Layout
Column_A
Column_C
Column_B
 
Select *...into Var_A,Var_B,Var_C  returns
Var_A=Column_A
Var_B=Column_C (!!!!!)
Var_C=Column_B (!!!!!)

which could lead to a conversion error.

There - that should make it as clear as mud!  :-)


-Greg
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Author Comment

by:akohan
Comment Utility

thanks to all.

regards,
ak
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Author Closing Comment

by:akohan
Comment Utility
Thanks
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