9

I am about to create an Application Form with UUID as its unique key (not primary key).

I got the error:

An exception of type 'System.Data.Entity.Core.EntityCommandExecutionException' occurred in EntityFramework.SqlServer.dll but was not handled in user code Additional information: An error occurred while executing the command definition. See the inner exception for details.

Connection String To DB:

 connectionString="Data Source=(localdb)\v11.0; 
                   Initial Catalog=FormsContext; 
                   Integrated Security=True; 
                   MultipleActiveResultSets=True;
                   AttachDbFilename=|DataDirectory|Forms.mdf"
 providerName="System.Data.SqlClient"

FormsContext.cs:

namespace ApplicationForm.Models
{
    public class FormsContext : DbContext
    {
        public FormsContext() : base("name=FormsContext")
        {
        }

        public System.Data.Entity.DbSet<ApplicationForm.Models.Form> Forms { get; set; }
...

The database is like this: 

 FormsContext->Forms->{id,uuid,first,last...}

I am not so sure what happened this time. Would anyone help me to go through this?

Edit/Resolution

I wasn't sure how to check Inner Exception and I did some research on this. So when I read the error message in the Inner Exception, I could solve my problem.

I found out what the bug was. The query field is 'firstname' but my table column name is 'first'. They did not match. Once I changed the DB column name, it was working again.

ΩmegaMan
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Luxing
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    `Additional information: An error occurred while executing the command definition. See the inner exception for details.` Did you check the inner exception? Please post the full exception message + stack trace. – sstan Jun 29 '15 at 14:27
  • Your database is throwing an exception on the query that EF is trying to run to select your models. The specific SQL exception will be included in the inner exception. – Nick Bailey Jun 29 '15 at 14:29
  • @sstan, Hi you are right. I wasn't sure how to check Inner Exception before. I did some research and found out that the query 'firstname' does not match with my db table column name 'first'. Thank you. – Luxing Jun 29 '15 at 14:36
  • You can provide an answer to your own question in the answer section. Or set mine as the answer...up to you. Regardless show that it is not an open question. :-) – ΩmegaMan Mar 17 '16 at 18:21

3 Answers3

14

found out what the bug was. The query field is 'firstname' but my table column name is 'first'. They did not match. Once I changed the DB column name, it was working again.

One must be diligent to keep each in sync if the database is always in flux.

Why?

EF is simply a set of mappings, a snapshot in time, and whether those mappings are to tables or stored procedures, it does not matter.

For any subtle change(s) to column names or foreign key constraints can have ripple effects to any old mappings and they need to be remapped/scaffolded into new structure(s); otherwise hence weird behaviors from old mappings.

At times, those effects can create obvious errors like you found or even more insidious non obvious logical errors which can provide working (compiled) software with subtle logic bugs. I have seen the logic bugs by experience and they do happen.

So always be wary to keep the EF mappings in sync.

I answered to a different EF question but in a similar vein.

I had run into a situation where in EF a mapped stored proc at runtime failed because an internal change in the stored proc saw that a sql cast had stripped out a column name from the result, and EF (mapped before the changed) failed. I have a screen shot in my answer which shows that EF/db changes can have a deleterious effect:

The data reader is incompatible . A member does not have a corresponding column in the data reader with the same name

ΩmegaMan
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9

In my case helped next:

1) press View Detail.. button:

enter image description here

2) Check your actual error:

enter image description here

Hope it helps for someone.

Vlad Pulichev
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1

Just in case this helps someone - I saw this error message. It turned out that I had changed the database associated with my EF model and hadn't set the connection string up properly.

Rachel Edge
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