使用ADO.NET时，每次数据库操作都要设置connection属性、建立connection、使用command、事务处理等，比较繁琐，有很多重复工作。能不能把这些繁琐的、常用的操作再封装一下，以更方便、安全地使用。下面这个类就是一种尝试：
using System;
using System.Data.SqlClient;
using System.Text;
using System.Data;
using System.Collections;
using System.Configuration;


public class DBAccess
{
/// <summary>
/// Declare the ole db required objects
/// </summary>


/// <summary>
/// An ole db adapter to act as the bridge to the database
/// </summary>
private SqlDataAdapter dbDataAdapter;
/// <summary>
/// The connection to the database
/// </summary>
private SqlConnection dbConnection;
/// <summary>
/// The command for doing the inserts
/// </summary>
private SqlCommand dbInsertCommand;
/// <summary>
/// The command for doing the deletes
/// </summary>
private SqlCommand dbDeleteCommand;
/// <summary>
/// The command for doing the updates
/// </summary>
private SqlCommand dbUpdateCommand;
/// <summary>
/// The command for doing the Selects
/// </summary>
private SqlCommand dbSelectCommand;

private SqlCommand dbSelectCommandofAdapter;

/// <summary>
/// The command for get dataset
/// </summary>
private SqlDataAdapter dataAdapterCommand;

/// <summary>
/// The data reader for the application
/// </summary>
public SqlDataReader dbDataReader;


/// <summary>
/// Declare an enum to allow internal tracking of commands
/// </summary>
enum COMMAND{ NONE, INSERT, UPDATE, DELETE, SELECT,DATASET };

/// <summary>
/// Internal member for tracking command progress
/// </summary>
private COMMAND command;

/// <summary>
/// String to hold error messages if a command fails
/// </summary>
private string error;

/// <summary>
/// Get a stored error message if ExecuteCommand fails
/// </summary>
public string ErrorMessage
{
get
{
return error;
}
}

/// <summary>
/// bool holder for is open
/// </summary>
private bool bOpen;

/// <summary>
/// Check to see if a data base is open
/// </summary>
public bool IsOpen
{
get
{
return bOpen;
}
}


/// <summary>
/// Declare a string object for the insert command
/// </summary>
public string InsertCommand
{
get
{
return dbInsertCommand.CommandText;
}
set
{
command = COMMAND.INSERT;
dbInsertCommand.CommandText = value;
}
}

/// <summary>
/// Declare a string object for the delete command
/// </summary>
public string DeleteCommand
{
get
{
return dbDeleteCommand.CommandText;
}
set
{
command = COMMAND.DELETE;
dbDeleteCommand.CommandText = value;
}
}

/// <summary>
/// Declare a string object for the update command
/// </summary>
public string UpdateCommand
{
get
{
return dbUpdateCommand.CommandText;
}
set
{
command = COMMAND.UPDATE;
dbUpdateCommand.CommandText = value;
}
}

/// <summary>
/// Declare a string object for the select command
/// </summary>
public string SelectCommand
{<