檢查ADO.NET / OLEDB連接是否存在，然后插入到DB

Question

我最初發布的問題是檢查是否存在ADO.NET/OLEDB連接類型。 正在解決的問題是，我想知道如何在插入數據庫時​​更改代碼。

例如，當連接類型是ADO.NET時，我們在連接類型中使用“Transaction”。

 SqlConnection connection = (SqlConnection)connections[_connectionName].AcquireConnection(transaction);

現在如果我有OLEDB連接（而不是ADO.NET），我想在這段代碼中處理這種情況。 我需要做什么。 對不起，如果我聽起來不夠技術，但我不是C＃人。 再次感謝您的幫助。

編輯我在這里粘貼整個代碼，因為我似乎無法使用OLEDB類型的連接。 我只能使用ADO.NET ...我知道它很簡單，但我不知道它是什么。

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.SqlClient;
using Microsoft.SqlServer.Dts.Runtime;
using System.Data.OleDb;
using System.Data.Common;

namespace AOC.SqlServer.Dts.Tasks

{

[DtsTask(
    DisplayName = "Custom Logging Task",
    Description = "Writes logging info into a table")]
public class CustomLoggingTask : Task
{

    private string _packageName;
    private string _taskName;
    private string _errorCode;
    private string _errorDescription;
    private string _machineName;
    private double _packageDuration;

    private string _connectionName;
    private string _eventType;
    private string _executionid;
    private DateTime _handlerdatetime;
    public string ConnectionName
    {
        set
        {
            _connectionName = value;
        }
        get
        {
            return _connectionName;
        }
    }


    public string Event
    {
        set
        {
            _eventType = value;
        }
        get
        {
            return _eventType;
        }
    }


    public override DTSExecResult Validate(Connections connections, VariableDispenser variableDispenser, IDTSComponentEvents componentEvents, IDTSLogging log)
    {
        const string METHOD_NAME = "CustomLoggingTask-Validate";

        try
        {

            if (string.IsNullOrEmpty(_eventType))
            {
                componentEvents.FireError(0, METHOD_NAME, "The event property must be specified", "", -1);
                return DTSExecResult.Failure;
            }


            if (string.IsNullOrEmpty(_connectionName))
            {
                componentEvents.FireError(0, METHOD_NAME, "No connection has been specified", "", -1);
                return DTSExecResult.Failure;
            }

            DbConnection connection = connections[_connectionName].AcquireConnection(null) as DbConnection;
            if (connection == null)
            {
                componentEvents.FireError(0, METHOD_NAME, "The connection is not a valid ADO.NET connection", "", -1);
                return DTSExecResult.Failure;
            }

            if (!variableDispenser.Contains("System::SourceID"))
            {
                componentEvents.FireError(0, METHOD_NAME, "No System::SourceID variable available. This task can only be used in an Event Handler", "", -1);
                return DTSExecResult.Failure;
            }

            return DTSExecResult.Success;
        }
        catch (Exception exc)
        {
            componentEvents.FireError(0, METHOD_NAME, "Validation Failed: " + exc.ToString(), "", -1);
            return DTSExecResult.Failure;
        }
    }


    public override DTSExecResult Execute(Connections connections, VariableDispenser variableDispenser, IDTSComponentEvents componentEvents, IDTSLogging log, object transaction)
    {
        try
        {
            string commandText =
@"INSERT INTO SSISLog (EventType, PackageName, TaskName, EventCode, EventDescription, PackageDuration, Host, ExecutionID, EventHandlerDateTime)
VALUES (@EventType, @PackageName, @TaskName, @EventCode, @EventDescription, @PackageDuration, @Host, @Executionid, @handlerdatetime)";

            ReadVariables(variableDispenser);
            DbConnection connection = connections[_connectionName].AcquireConnection(transaction) as DbConnection;
            //SqlConnection connection = (SqlConnection)connections[_connectionName].AcquireConnection(transaction);
            DbCommand command = null;
            //using (SqlCommand command = new SqlCommand())
            if (connection is SqlConnection)
                command = new SqlCommand();
            else if (connection is OleDbConnection)
                command = new OleDbCommand();

            {
                command.CommandText = commandText;
                command.CommandType = CommandType.Text;
                command.Connection = connection;

                command.Parameters.Add(new SqlParameter("@EventType", _eventType));
                command.Parameters.Add(new SqlParameter("@PackageName", _packageName));
                command.Parameters.Add(new SqlParameter("@TaskName", _taskName));
                command.Parameters.Add(new SqlParameter("@EventCode", _errorCode ?? string.Empty));
                command.Parameters.Add(new SqlParameter("@EventDescription", _errorDescription ?? string.Empty));
                command.Parameters.Add(new SqlParameter("@PackageDuration", _packageDuration));
                command.Parameters.Add(new SqlParameter("@Host", _machineName));
                command.Parameters.Add(new SqlParameter("@ExecutionID", _executionid));
                command.Parameters.Add(new SqlParameter("@handlerdatetime", _handlerdatetime));
                command.ExecuteNonQuery();
            }

            return DTSExecResult.Success;
        }
        catch (Exception exc)
        {
            componentEvents.FireError(0, "CustomLoggingTask-Execute", "Task Errored: " + exc.ToString(), "", -1);
            return DTSExecResult.Failure;
        }
    }


    private void ReadVariables(VariableDispenser variableDispenser)
    {
        variableDispenser.LockForRead("System::StartTime");
        variableDispenser.LockForRead("System::PackageName");
        variableDispenser.LockForRead("System::SourceName");
        variableDispenser.LockForRead("System::MachineName");
        variableDispenser.LockForRead("System::ExecutionInstanceGUID");
        variableDispenser.LockForRead("System::EventHandlerStartTime");
        bool includesError = variableDispenser.Contains("System::ErrorCode");
        if (includesError)
        {
            variableDispenser.LockForRead("System::ErrorCode");
            variableDispenser.LockForRead("System::ErrorDescription");
        }

        Variables vars = null;
        variableDispenser.GetVariables(ref vars);

        DateTime startTime = (DateTime)vars["System::StartTime"].Value;
        _packageDuration = DateTime.Now.Subtract(startTime).TotalSeconds;
        _packageName = vars["System::PackageName"].Value.ToString();
        _taskName = vars["System::SourceName"].Value.ToString();
        _machineName = vars["System::MachineName"].Value.ToString();
        _executionid = vars["System::ExecutionInstanceGUID"].Value.ToString();
        _handlerdatetime = (DateTime)vars["System::EventHandlerStartTime"].Value;
        if (includesError)
        {
            _errorCode = vars["System::ErrorCode"].Value.ToString();
            _errorDescription = vars["System::ErrorDescription"].Value.ToString();
        }

        // release the variable locks.
        vars.Unlock();

        // reset the dispenser
        variableDispenser.Reset();
    }
}

}

Answer 1

由於connections[_connectionName].AcquireConnection(transaction); 你的代碼的一部分與SqlConnection無關（你之后只是轉換為SqlConnection ），你應該能夠聲明與var connection ，然后對你需要的connection做任何事情。

var connection = connections[_connectionName].AcquireConnection(transaction);

獲得connection對象后，可以將其轉換為所需的任何連接類型，並執行與將connection變量聲明為該類型相同的操作。 例如

if(connection is DbConnection)
{
    // ((DbConnection)connection).SomethingToDoWithDbConnection
}

if(connection is SqlConnection)
{
    // ((SqlConnection)connection).SomethingToDoWithSqlConnection
}

if(connection is OleDbConnection)
{
    // ((OleDbConnection)connection).SomethingToDoWithOleDbConnection
}

Answer 2

在System.Data.Common您將找到具體數據庫類型（SqlConnection，OleDbConnection，SqlDataAdapter等）都派生自的基類。

如果你使用那些，即。 DbConnection ，使用哪個具體實現並不重要，代碼將是相同的。

DbConnection connection = connections[_connectionName]
    .AcquireConnection(transaction) as DbConnection;

然后，您可以調用DbConnection.BeginTransaction()而不是SqlConnection.BeginTransaction() ，無論連接是OleDbConnection還是SqlConnection都無關緊要。

只要您需要調用的所有方法都從DbConnection繼承，這將起作用。

其余的代碼也可以使用基類型，所以DbTransaction ， DbDataAdapter ， DbDataReader等。

因為您的AquireConnection()方法不返回具體的連接類型，所以您可以利用依賴注入並編寫非特定於實現的代碼。

---

具體來說，對於插入，您將具有以下內容：

DbCommand command = null;
if (connection is SqlConnection)
   command = new SqlCommand();
else if (connection is OleDbConnection)
   command = new OleDbCommand();
command.CommandText = "INSERT STATEMENT HERE";
command.Connection = connection;
command.ExecuteNonQuery();

不要忘記你需要connection.Close() 。在某處關閉connection.Close() 。 （如果使用ConnectionManager，則為ReleaseConnection）