How can I get an error message that happens when using ExecuteNonQuery()?

Question

I am executing a command in this way:

var Command = new SqlCommand(cmdText, Connection, tr);

Command.ExecuteNonQuery();

In the command there is an error, however .NET does not throw any error message. How could I know that the command did not executed properly, and how to get the exception?

Answer 1

.NET does indeed raise an error message... if the severity is 16 or above (since it throws an exception) - the message will be in the exception .Message . If you are using RAISERROR with a lower severity (or using PRINT ) then you will have to subscribe to the InfoMessage event on the connection .

Answer 2

You'll only get an exception in C# if your error's severity is 16 or above. If you are using a PRINT, you won't get an exception in .NET.

If you can edit the raise error code, this would cause a SqlException in C#:

RAISERROR('Some error message', 16, 1)

You can then get to each individual error in the SqlException.Errors collection.

Just a side-note - SQL Server will continue to run commands after the RAISERROR if you don't RETURN directly afterwards. If you don't return, you can get multiple errors back.

Answer 3

Only high severity errors will be thrown back in ExecuteNonQuery. There is another scenario that I have observed with OdbcCommand.ExecuteNonQuery() method. May be this is true for SqlCommand.ExecuteNonQuery() as well. If the SQL contained in the CommandText property is a single statement (Example: INSERT INTO table (col1,col2) VALUES (2,'ABC'); ) and if there is a foreign key violation or primary key violation in the above statement ExecuteNonQuery will throw an exception. However, if your CommandText is a batch where you have more than one SQL Statements seperated by semi colon (Like Several INSERTS or UPDATES) and if one of them fails ExecuteNonQuery does not throw an exception back. You need to be explicitly checking for the number of records affected returned by the method. Simply putting the code in a try{}Catch{} wont help.

Answer 4

Inspired by the work of M Hassan, Stefan Steiger, and Mark Gravell in this thread, here is a minimum proof-of-concept example of what is going on here:

private static void DoSql()
{
    // Errors of severity level of 10 or less 
    // will NOT bubble up to .Net as an Exception to be caught in the usual way
    const string sql = @"RAISERROR('A test error message of low severity', 10, 1)";

    using (SqlConnection conn = new SqlConnection(myConnString))
    {
        conn.Open();

        // Hook up my listener to the connection message generator
        conn.InfoMessage += new SqlInfoMessageEventHandler(MySqlMessageHandler);

        using (SqlCommand cmd = new SqlCommand(sql, conn))
        {
            cmd.ExecuteNonQuery();
            // code happily carries on to this point
            // despite the sql Level 10 error that happened above
        }
    }
}


private static void MySqlMessageHandler(object sender, SqlInfoMessageEventArgs e)
{
    // This gets all the messages generated during the execution of the SQL, 
    // including low-severity error messages.
    foreach (SqlError err in e.Errors)
    {
        // TODO: Something smarter than this for handling the messages
        MessageBox.Show(err.Message);
    }
}

Answer 5

I found this to work well for me in a WCF service with Oracle ODP.Net -

            try
            {
                cmd.Connection = conn;
                conn.Open();
                cmd.ExecuteNonQuery();
            }
            catch (OracleException oex)
            {
                string errmsg = oex.Message;
                Logger.Instance.WriteLog(@"Some error --> " + errmsg);
                throw new Exception(errmsg);
            }
            catch (Exception ex)
            {
                throw ex;
            }
            finally
            {
                cleanup...
            }

Answer 6

this code when the command is finsth, combine with try cath, return the error:

SqlCommand.EndExecuteNonQuery(result) 

and this is my full class code:

Imports System.Data.SqlClient
Imports System.DirectoryServices.ActiveDirectory

Class clsExecuteAsync


    Public Event EnProceso(Identificador As Integer, Mensaje As String)
    Public Event Finalizado(IDentificador As Integer, Mensaje As String)
    Public Event CancelarProcesoEnEjecucion(Identificador As Integer, ByRef Cancel As Boolean)



    Dim Cancelar As Boolean

    Sub CancelarProceso()
        Cancelar = True
    End Sub


    Function test() As Boolean
        ' This is a simple example that demonstrates the usage of the
        ' BeginExecuteNonQuery functionality.
        ' The WAITFOR statement simply adds enough time to prove the
        ' asynchronous nature of the command.
        Dim commandText As String = "UPDATE Production.Product SET ReorderPoint = ReorderPoint + 1 " & "WHERE ReorderPoint Is Not Null;" & "WAITFOR DELAY '0:0:3';" & "UPDATE Production.Product SET ReorderPoint = ReorderPoint - 1 " & "WHERE ReorderPoint Is Not Null"
        Return (RunCommandAsynchronously(0, commandText, GetConnectionString()))
        Console.WriteLine("Press ENTER to continue.")
        Console.ReadLine()

    End Function

    Function ExecuteAsync(Identificador As Integer, Sql As String, Optional CadenaConexion As String = "") As String
        If CadenaConexion = "" Then
            CadenaConexion = clsIni.LeeIni("Provider")
        End If

        Return RunCommandAsynchronously(Identificador, Sql, CadenaConexion)

    End Function

    Function RunCommandAsynchronously(Identificador As Integer, commandText As String, connectionString As String) As String
        ' Given command text and connection string, asynchronously execute
        ' the specified command against the connection. For this example,
        ' the code displays an indicator as it is working, verifying the
        ' asynchronous behavior.
        Dim Resultado As String = ""
        Try

            Dim connection As SqlConnection
            Dim SqlCommand As SqlCommand

            connection = New SqlConnection(connectionString)
            Dim count As Integer = 0

            'testint to catch the error, but not run for me
            AddHandler connection.InfoMessage, AddressOf ErrorEnConexion


            SqlCommand = New SqlCommand(commandText, connection)
            connection.Open()
            Dim result As IAsyncResult = SqlCommand.BeginExecuteNonQuery()
            While Not result.IsCompleted
                Console.WriteLine("Waiting ({0})", count = count + 1)
                ' Wait for 1/10 second, so the counter
                ' does not consume all available resources
                ' on the main thread.
                System.Threading.Thread.Sleep(100)
                RaiseEvent EnProceso(Identificador, commandText)
                Application.DoEvents()

                If Cancelar Then
                    Cancelar = False

                    'cancelar 
                    Dim Cancel As Boolean = False
                    RaiseEvent CancelarProcesoEnEjecucion(Identificador, Cancel)

                    If Cancel = False Then
                        Resultado = "Cancelado"
                        GoTo SALIR
                    End If

                End If

            End While

            'Console.WriteLine("Command complete. Affected {0} rows.", Command.EndExecuteNonQuery(Result))

            '   MsgBox("El comando se ejecutó. " & SqlCommand.EndExecuteNonQuery(result), MsgBoxStyle.Information)

            'detect error: this code lunch and error: Cath with try cacth code
            SqlCommand.EndExecuteNonQuery(result)

            RaiseEvent Finalizado(Identificador, SqlCommand.EndExecuteNonQuery(result))

            Resultado = "OK"

        Catch ex As SqlException
            Console.WriteLine("Error ({0}): {1}", ex.Number, ex.Message)
            Resultado = ex.Message


        Catch ex As InvalidOperationException
            Console.WriteLine("Error: {0}", ex.Message)
            Resultado = ex.Message
        Catch ex As Exception
            ' You might want to pass these errors
            ' back out to the caller.
            Console.WriteLine("Error: {0}", ex.Message)
            Resultado = ex.Message
        End Try


SALIR:
        Return Resultado

    End Function

    Private Sub ErrorEnConexion(sender As Object, e As SqlInfoMessageEventArgs)
        MsgBox(e.Message)

    End Sub


    Private Function GetConnectionString() As String
        ' To avoid storing the connection string in your code,
        ' you can retrieve it from a configuration file.
        ' If you have not included "Asynchronous Processing=true" in the
        ' connection string, the command is not able
        ' to execute asynchronously.
        Return "Data Source=(local);Integrated Security=SSPI;" & "Initial Catalog=AdventureWorks; Asynchronous Processing=true"

    End Function


End Class

Answer 7

Try the below.

PS: Just because you use a transaction, doesn't mean you can neglect handling exceptions and rollbacks.

 public static void MessageEventHandler( object sender, SqlInfoMessageEventArgs e ) {
         foreach( SqlError error in e.Errors ) {
            Console.WriteLine("problem with sql: "+error);
            throw new Exception("problem with sql: "+error);
         }
      }
      public static int executeSQLUpdate(string database, string command) {
         SqlConnection connection = null;
         SqlCommand sqlcommand = null;
         int rows = -1;
         try {
            connection = getConnection(database);
            connection.InfoMessage += new SqlInfoMessageEventHandler( MessageEventHandler );
            sqlcommand = connection.CreateCommand();
            sqlcommand.CommandText = command;
            connection.Open();
            rows = sqlcommand.ExecuteNonQuery();
          } catch(Exception e) {
            Console.Write("executeSQLUpdate: problem with command:"+command+"e="+e);
            Console.Out.Flush();
            throw new Exception("executeSQLUpdate: problem with command:"+command,e);
         } finally {
            if(connection != null) { connection.Close(); }
         } 
         return rows;
      }

And this is proper transaction handling:

//public static void ExecuteInTransaction(Subtext.Scripting.SqlScriptRunner srScriptRunner)
        public override void ExecuteInTransaction(string strSQL)
        {

            System.Data.Odbc.OdbcTransaction trnTransaction = null;

            try
            {


                System.Threading.Monitor.Enter(m_SqlConnection);
                if (isDataBaseConnectionOpen() == false)
                    OpenSQLConnection();

                trnTransaction = m_SqlConnection.BeginTransaction();

                try
                {
                    /*
                    foreach (Subtext.Scripting.Script scThisScript in srScriptRunner.ScriptCollection)
                    {
                        System.Data.Odbc.OdbcCommand cmd = new System.Data.Odbc.OdbcCommand(scThisScript.ScriptText, m_sqlConnection, trnTransaction);
                        cmd.ExecuteNonQuery();
                    }
                    */

                    // pfff, mono C# compiler problem...
                    // System.Data.Odbc.OdbcCommand cmd = new System.Data.Odbc.OdbcCommand(strSQL, m_SqlConnection, trnTransaction);
                    System.Data.Odbc.OdbcCommand cmd = this.m_SqlConnection.CreateCommand();
                    cmd.CommandText = strSQL;

                    cmd.ExecuteNonQuery();

                    trnTransaction.Commit();
                } // End Try
                catch (System.Data.Odbc.OdbcException exSQLerror)
                {
                    Log(strSQL);
                    Log(exSQLerror.Message);
                    Log(exSQLerror.StackTrace);
                    trnTransaction.Rollback();
                } // End Catch
            } // End Try
            catch (Exception ex)
            {
                Log(strSQL);
                Log(ex.Message);
                Log(ex.StackTrace);
            } // End Catch
            finally
            {
                strSQL = null;
                if(m_SqlConnection.State != System.Data.ConnectionState.Closed)
                    m_SqlConnection.Close();
                System.Threading.Monitor.Exit(m_SqlConnection);
            } // End Finally


        } // End Sub ExecuteInTransaction

Answer 8

You catch the SqlException using try/catch

 try
  {
       //.......
    Command.ExecuteNonQuery();      
   }
    catch (SqlException ex)
     {   
       log (SqlExceptionMessage(ex).ToString());
     }

The following Method Catch details of SqlException which can be logged or displayed to user

  public StringBuilder SqlExceptionMessage(SqlException ex)
    {
        StringBuilder sqlErrorMessages = new StringBuilder("Sql Exception:\n");

        foreach (SqlError error in ex.Errors)
        {
            sqlErrorMessages.AppendFormat("Mesage: {0}\n", error.Message)
                .AppendFormat("Severity level: {0}\n", error.Class)
                .AppendFormat("State: {0}\n", error.State)
                .AppendFormat("Number: {0}\n", error.Number)
                .AppendFormat("Procedure: {0}\n", error.Procedure)
                .AppendFormat("Source: {0}\n", error.Source)
                .AppendFormat("LineNumber: {0}\n", error.LineNumber)
                .AppendFormat("Server: {0}\n", error.Server)
                .AppendLine(new string('-',error.Message.Length+7));

        }
        return sqlErrorMessages;
    }

The Generated message look like:

 Sql Exception:
 Mesage: Error converting data type nvarchar to datetime.
 Severity level: 16
 State: 5
 Number: 8114
 Procedure: Sales by Year
 Source: .Net SqlClient Data Provider
 LineNumber: 0
 Server: myserver
 -------------------------------------------------------