我正在以这种方式执行命令：
var Command = new SqlCommand(cmdText, Connection, tr);
Command.ExecuteNonQuery();
在命令中有一个错误，但是 .NET 不会抛出任何错误消息。我怎么知道命令没有正确执行，以及如何获取异常？
【问题讨论】：
NonQuery 方法 - 如果您使用实际名称真的会更清楚...编辑...
标签： c# sql ado.net sqlcommand
.NET 确实会引发错误消息...如果严重性为 16 或更高（因为它会引发异常） - 消息将在异常 .Message 中。如果您使用的是具有较低严重性的RAISERROR（或使用PRINT），那么您必须订阅InfoMessage event on the connection。
【讨论】：
ExecuteNonQuery() 使用TDS（并因此看到错误），但ExecuteScalar() 不会使用它？我希望ExecuteNonQuery() 根本不消耗任何东西，尽管我实际上更喜欢这样做。
ExecuteReader 的问题。但是，我的研究（*.com/questions/1010383/…、*.com/a/2400019/177333、sqlservercentral.com/Forums/Topic1070081-392-1.aspx#bm1070131）表明，如果在第一个结果集之后，ExecuteScalar 也不会发现错误。我想最好的方法就是尝试一下。
select ...; raiserror(...) 需要您执行DataReader.NextResult() 才能发现错误。
试试下面的。
PS：仅仅因为您使用事务，并不意味着您可以忽略处理异常和回滚。
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;
}
这是正确的事务处理：
//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
【讨论】：
using 和 lock 在这里更合适；此外，您不会重新抛出，并且在每个级别进行日志记录都是多余的（这就是 .StackTrace 的用途）。那无声无息地失败了-非常糟糕，IMO。为什么要锁定连接？如果您处于两个线程甚至可以看到相同连接的位置，那么您做错了，IMO。如果有的话，在我看来，这就像一个完美的例子，说明如何不进行错误处理。
conn.Open(); 存在 - 实际上，在内部我们使用 EnsureOpen() entension-method，它使用 IDisposable 并打开它如果未打开并关闭它在处置（如果它打开它） - 方便的小包装实用程序方法。整个“我们重复使用连接多少”与我试图说明的要点无关 - 所以我没有关注那个
如果您的错误的严重性为 16 或更高，您只会在 C# 中获得异常。如果您使用的是 PRINT，则在 .NET 中不会出现异常。
如果您可以编辑 raise 错误代码，这将导致 C# 中的 SqlException：
RAISERROR('Some error message', 16, 1)
然后您可以访问 SqlException.Errors 集合中的每个单独的错误。
附带说明 - 如果您之后不直接 RETURN，SQL Server 将继续在 RAISERROR 之后运行命令。如果不返回，可能会返回多个错误。
【讨论】：
在 ExecuteNonQuery 中只会抛出严重性较高的错误。我使用 OdbcCommand.ExecuteNonQuery() 方法观察到了另一种情况。可能这对于 SqlCommand.ExecuteNonQuery() 也是如此。如果 CommandText 属性中包含的 SQL 是单个语句（例如：INSERT INTO table (col1,col2) VALUES (2,'ABC'); ）并且上述语句中存在外键违规或主键违规 ExecuteNonQuery会抛出异常。但是，如果您的 CommandText 是一个批处理，其中您有多个用分号分隔的 SQL 语句（如几个 INSERTS 或 UPDATES），并且如果其中一个失败，则 ExecuteNonQuery 不会抛出异常。您需要明确检查该方法返回的受影响记录数。简单地将代码放在 try{}Catch{} 中不会有帮助。
【讨论】：
您使用 try/catch 捕获 SqlException
try
{
//.......
Command.ExecuteNonQuery();
}
catch (SqlException ex)
{
log (SqlExceptionMessage(ex).ToString());
}
以下方法捕获可以记录或显示给用户的 SqlException 详细信息
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;
}
生成的消息如下所示：
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
-------------------------------------------------------
【讨论】：
受 M Hassan、Stefan Steiger 和 Mark Gravell 在此线程中的工作的启发，以下是此处发生的最小概念验证示例：
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);
}
}
【讨论】：
我发现这在使用 Oracle ODP.Net 的 WCF 服务中非常适合我 -
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...
}
【讨论】：
这个代码当命令为finsth时，结合try cath，返回错误：
SqlCommand.EndExecuteNonQuery(result)
这是我的完整课程代码：
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
【讨论】：