mysql - 从使用不同数据库的 DbConnection 派生类

Question

我计划编写一个可以同时适用于 SQL Server 和 MySQL 的 DataConnection 库。

由于SqlConnection和MySqlConnection都是从DbConnection派生的，所以我创建了一个派生自它的类MyDBConnection

这是我到目前为止的代码，

class MyDBConnection : DbConnection
{
   private MyDBConnection connection;
   public MyDBConnection(String connectionString, String dbType)
   {
      if (dbType == "SqlServer")
      {
         SqlConnection sqlConnection = new SqlConnection(connectionString);
        //return myDBConnection as SqlConnection;
      }
      else if(dbType == "MySql")
      {
        MySqlConnection mysqlConnection = new MySqlConnection(connectionString);
        //return myDBConnection as mysqlConnection;
      }
  }
}

但是后来我陷入了如何进行的困境，这是否可行？

Answer 1

首先，我不会实现DBConnection，我会继承IDbConnection。您需要对您使用的所有内容(如命令、数据适配器、事务等)执行相同的操作。我不太擅长 C#，所以我将其从 VB 转换，希望它转换成功

using System;
using System.Collections;
using System.Collections.Generic;
using System.Data;
using System.Diagnostics;
class MyDBConnection : IDbConnection
{

    public enum DBType
    {
        SqlServer,
        MySql
    }

    private DBType _DbType;

    private string _ConnString;
    public MyDBConnection(String ConnectionString, DBType ConnType)
    {
        _DbType = ConnType;
        _ConnString = ConnectionString;
    }

    public IDbTransaction BeginTransaction()
    {

    }

    public IDbTransaction BeginTransaction(IsolationLevel il)
    {

    }


    public void ChangeDatabase(string databaseName)
    {
    }


    public void Close()
    {
    }

    public string ConnectionString { get; set; }

    public int ConnectionTimeout {

        get { }
    }

    public IDbCommand CreateCommand()
    {

    }

    public string Database {

        get { }
    }


    public void Open()
    {
    }

    public ConnectionState State {

        get { }
    }

    #region "IDisposable Support"
        // To detect redundant calls
    private bool disposedValue;

    // IDisposable
    protected virtual void Dispose(bool disposing)
    {
        if (!this.disposedValue) {
            if (disposing) {
                // TODO: dispose managed state (managed objects).
            }

            // TODO: free unmanaged resources (unmanaged objects) and override Finalize() below.
            // TODO: set large fields to null.
        }
        this.disposedValue = true;
    }

    // TODO: override Finalize() only if Dispose(ByVal disposing As Boolean) above has code to free unmanaged resources.
    //Protected Overrides Sub Finalize()
    //    ' Do not change this code.  Put cleanup code in Dispose(ByVal disposing As Boolean) above.
    //    Dispose(False)
    //    MyBase.Finalize()
    //End Sub

    // This code added by Visual Basic to correctly implement the disposable pattern.
    public void Dispose()
    {
        // Do not change this code.  Put cleanup code in Dispose(disposing As Boolean) above.
        Dispose(true);
        GC.SuppressFinalize(this);
    }
    #endregion

}