三层架构之数据库访问层完全篇(C#)

using System;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;

namespace DbBase
{

public abstract class Base
{

#region "Fields of base calss"

protected static string strConn = ConfigurationSettings.AppSettings["strConnection"];

protected static string strSQL;

#endregion


#region "Properties of base class"
}

#endregion


#region "Functions of base class"
public Base()
{
//
// TODO: Add constructor logic here
//
}

///

/// executing SQL commands
///

/// string
/// return int
protected static int ExecuteSql(string strSQL)
{
SqlConnection myCn = new SqlConnection(strConn);
SqlCommand myCmd = new SqlCommand(strSQL,myCn);
try
{
myCn.Open();
myCmd.ExecuteNonQuery();
return 0;
}
catch(System.Data.SqlClient.SqlException e)
{
throw new Exception(e.Message);
}
finally
{
myCmd.Dispose();
myCn.Close();
}
}


///

///executing SQL commands
///

/// 要执行的SQL语句,为字符串类型string
/// 返回执行情况,整形int
protected static int ExecuteSqlEx(string strSQL)
{
SqlConnection myCn = new SqlConnection(strConn);
SqlCommand myCmd = new SqlCommand(strSQL,myCn);

try
{
myCn.Open();
SqlDataReader myReader = myCmd.ExecuteReader();
if(myReader.Read())
{
return 0;
}
else
{
throw new Exception("Value Unavailable!");
}
}
catch(System.Data.SqlClient.SqlException e)
{
throw new Exception(e.Message);
}
finally
{
myCmd.Dispose();
myCn.Close();
}
}


///

/// get dataset
///

/// (string)
/// (DataSet)
protected static DataSet ExecuteSql4Ds(string strSQL)
{
SqlConnection myCn = new SqlConnection(strConn);
try
{
myCn.Open();
SqlDataAdapter sda = new SqlDataAdapter(strSQL,myCn);
DataSet ds = new DataSet("ds");
sda.Fill(ds);
return ds;
}
catch(System.Data.SqlClient.SqlException e)
{
throw new Exception(e.Message);
}
finally
{
myCn.Close();
}
}


///

/// get single value
///

/// (string)
/// (int)
protected static int ExecuteSql4Value(string strSQL)
{
SqlConnection myCn = new SqlConnection(strConn);
SqlCommand myCmd = new SqlCommand(strSQL,myCn);
try
{
myCn.Open();
object r = myCmd.ExecuteScalar();
if(Object.Equals(r,null))
{
throw new Exception("value unavailable！");
}
else
{
return (int)r;
}
}
catch(System.Data.SqlClient.SqlException e)
{
throw new Exception(e.Message);
}
finally
{
myCmd.Dispose();
myCn.Close();
}
}


///

/// get object
///

/// (string)
/// (object)
protected static object ExecuteSql4ValueEx(string strSQL)
{
SqlConnection myCn = new SqlConnection(strConn);
SqlCommand myCmd = new SqlCommand(strSQL,myCn);
try
{
myCn.Open();
object r = myCmd.ExecuteScalar();
if(Object.Equals(r,null))
{
throw new Exception("object unavailable!");
}
else
{
return r;
}
}
catch(System.Data.SqlClient.SqlException e)
{
throw new Exception(e.Message);
}
finally
{
myCmd.Dispose();
myCn.Close();
}
}


///

/// execute multipul SQL commands
///

/// string
/// int
protected static int ExecuteSqls(string[] strSQLs)
{
SqlConnection myCn = new SqlConnection(strConn);
SqlCommand myCmd = new SqlCommand();
int j=strSQLs.Length;

try
{
myCn.Open();
}
catch(System.Data.SqlClient.SqlException e)
{
throw new Exception(e.Message);
}
SqlTransaction myTrans = myCn.BeginTransaction();

try
{
myCmd.Connection = myCn;
myCmd.Transaction = myTrans;

foreach(string str in strSQLs)
{
myCmd.CommandText = str;
myCmd.ExecuteNonQuery();
}
myTrans.Commit();
return 0;
}
catch(System.Data.SqlClient.SqlException e)
{
myTrans.Rollback();
throw new Exception(e.Message);
}
finally
{
myCmd.Dispose();
myCn.Close();
}
}

#endregion
}
}