.Net---Sql数据库操作通用类库

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


namespace DataBaseOperate
{
 /// <summary>
 /// ConnDB 的摘要说明。
 /// </summary>
 public class ConnDB
 {
  protected SqlConnection Connection;
  public string connectionString;

  /// <summary>
  /// 默认构造函数
  /// </summary>
  public ConnDB()
  {
   string connStr;
   try
   {
   connStr = System.Configuration.ConfigurationManager.ConnectionStrings["conStr"].ToString();
   connectionString = connStr;
   Connection = new SqlConnection(connectionString);
   }
   catch (Exception)
   {

   }
  }


  /// <summary>
  /// 带参数的构造函数
  /// </summary>
  /// <param name="newConnectionString">数据库联接字符串</param>
  public ConnDB(string newConnectionString)
  {
   connectionString = newConnectionString;
   Connection = new SqlConnection(connectionString);
  }


  /// <summary>
  /// 完成SqlCommand对象的实例化-------本函数不需要显示调用
  /// </summary>
  /// <param name="storedProcName"></param>
  /// <param name="parameters"></param>
  /// <returns></returns>
  private SqlCommand BuildCommand(string storedProcName,IDataParameter[] parameters)
  {
   SqlCommand command = BuildQueryCommand(storedProcName,parameters);
   command.Parameters.Add(new SqlParameter("ReturnValue",SqlDbType.Int,4,ParameterDirection.ReturnValue,false,0,0,string.Empty,DataRowVersion.Default,null));
   return command;
  }


  /// <summary>
  /// 创建新的SQL命令对象(存储过程)----------在BuildCommand函数中使用,不需要显示调用
  /// </summary>
  /// <param name="storedProcName"></param>
  /// <param name="parameters"></param>
  /// <returns></returns>
  private SqlCommand BuildQueryCommand(string storedProcName,IDataParameter[] parameters)
  {
   SqlCommand command = new SqlCommand(storedProcName,Connection);
   command.CommandType = CommandType.StoredProcedure;
   foreach (SqlParameter parameter in parameters)
   {
    command.Parameters.Add(parameter);
   }
   return command;
  }


  /// <summary>
  /// 执行存储过程,无返回值
  /// </summary>
  /// <param name="storedProcName"></param>
  /// <param name="parameters"></param>
  public void RunProcedure_ReturnNull(string storedProcName,IDataParameter[] parameters)
  {
   Connection.Open();
   SqlCommand command;
   command=BuildQueryCommand(storedProcName,parameters);
   command.ExecuteNonQuery();
   Connection.Close();
  }


  /// <summary>
  /// 执行存储过程，返回执行操作影响的行数目
  /// </summary>
  /// <param name="storedProcName"></param>
  /// <param name="parameters"></param>
  /// <param name="rowsAffected"></param>
  /// <returns></returns>
  public int RunProcedure_ReturnEffectRows(string storedProcName,IDataParameter[] parameters,out int rowsAffected)
  {
   int result;
   Connection.Open();
   SqlCommand command = BuildCommand(storedProcName,parameters);
   rowsAffected = command.ExecuteNonQuery();
   result = (int)command.Parameters["ReturnValue"].Value;
   Connection.Close();

   return result;
  }
  

  /// <summary>
  /// 重载RunProcedure把执行存储过程的结果放在SqlDataReader中
  /// </summary>
  /// <param name="storedProcName"></param>
  /// <param name="parameters"></param>
  /// <returns></returns>
  public SqlDataReader RunProcedure_ReturnDataReader(string storedProcName, IDataParameter[] parameters)
  {
   SqlDataReader returnReader;
   Connection.Open();
   SqlCommand command = BuildQueryCommand(storedProcName,parameters);
   command.CommandType = CommandType.StoredProcedure;
   returnReader = command.ExecuteReader(CommandBehavior.CloseConnection);
   return returnReader;
  }


  /// <summary>
  /// 重载RunProcedure把执行存储过程的结果存储在DataSet中和表tableName为可选参数
  /// </summary>
  /// <param name="storedProcName"></param>
  /// <param name="parameters"></param>
  /// <param name="tableName"></param>
  /// <returns></returns>
  public DataSet RunProcedure_ReturnDataSet(string storedProcName,IDataParameter[] parameters,params string[] tableName)
  {
   DataSet dataSet = new DataSet();
   Connection.Open();
   SqlDataAdapter sqlDA = new SqlDataAdapter();
   sqlDA.SelectCommand = BuildQueryCommand(storedProcName,parameters);
   string flag;
   flag = "";
   for(int i=0;i<tableName.Length;i++)
    flag = tableName[i];
   if (flag!="")
    sqlDA.Fill(dataSet,tableName[0]);
   else
    sqlDA.Fill(dataSet);
   Connection.Close();
   return dataSet;
  }

  
  /// <summary>
  /// 执行SQL语句，返回数据到DataSet中
  /// </summary>
  /// <param name="sql"></param>
  /// <returns></returns>
  public DataSet ExecSQL_ReturnDataSet(string sql)
  {
   DataSet dataSet=new DataSet();
   Connection.Open();
   SqlDataAdapter sqlDA=new SqlDataAdapter(sql,Connection);
   sqlDA.Fill(dataSet,"objDataSet");
   Connection.Close();
   return dataSet;
  }
  

  /// <summary>
  /// 执行SQL语句，返回 DataReader
  /// </summary>
  /// <param name="sql"></param>
  /// <returns></returns>
  public SqlDataReader ExecSQL_ReturnDataReader(String sql)
  {
   Connection.Open();
   SqlCommand command = new SqlCommand(sql,Connection);
   SqlDataReader dataReader = command.ExecuteReader();

   return dataReader;
  }


  /// <summary>
  /// 执行SQL语句，返回结果集的记录数
  /// </summary>
  /// <param name="sql"></param>
  /// <returns></returns>
  public int ExecSql_ReturnRecordCount(string sql)
  {
   int recordCount = 0;

   Connection.Open();
   SqlCommand command = new SqlCommand(sql,Connection);
   SqlDataReader dataReader = command.ExecuteReader();

   while(dataReader.Read())
   {
    recordCount++;
   }
   dataReader.Close();
   Connection.Close();

   return recordCount;
  }


  /// <summary>
  /// 执行一条非查询的SQL语句
  /// </summary>
  /// <param name="sql"></param>
  /// <returns></returns>
  public bool ExecSql_NonQuery(string sql)
  {
   bool successState = false;

   Connection.Open();
   //创建事务-------------
   SqlTransaction myTrans = Connection.BeginTransaction();
   SqlCommand command = new SqlCommand(sql,Connection,myTrans);
   try
   {
    command.ExecuteNonQuery();
    myTrans.Commit();
	//-----------提交事务
    successState = true;
   }
   catch
   {
    myTrans.Rollback();
   }
   finally
   {
    Connection.Close();
   }

   return successState;
  }


  /// <summary>
  /// 关闭数据库联接
  /// </summary>
  public void Close()
  {
   Connection.Close();
  }

 }//end class
}//end namespace 

以上是代码 ,大多都是改的别人的代码.总体来说没什么难度!注释已经很详细了!其中的IDataParameter接口需要说一下!

 

  从表面上看，IDataParameter[]的实例就是一个IDataParameter的数组。而IDataParameter实际上是不能直接实例化的，所以这种数组其实很不常见，仅仅会出现在函数的入口参数里面。且多以params的形式出现。这样做的好处是令这个函数可以对付所有的数据库。

        IDataParameter[]简单的说来，就是可以包含任何数据库参数的数组，这些参数可以是SqlParameter或者OleDbParameter，但是，IDataParameter[]不可以直接从SqlParameter[]转换过来。

        下面是三种创建IDataParameter[]的方法：

 

         一、直接构造：
                                IDataParameter[] parameters = new IDataParameter[]{ sqlparameter1, sqlparameter2, new SqlParameter(...) }

                                亦可以这样:

                               

            IDataParameter[] param = new IDataParameter[3];
            param[0]=new SqlParameter("@co_code","PQtech");
            param[1]=new SqlParameter("@clnt_type","C");
            param[2]=new SqlParameter("@clnt_code","");

 

         二、通过ArrayList转换。

                               ArrayList paramlist = new ArrayList()
                               paramlist.Add( sqlparameter1 );
                                              ....
                                              ....

                               IDataParameter param = (IDataParameter[]) paramlist.ToArray( typeof( IDataParameter ) );

 

         三、通过其他Parameter类型的数组创建。

 

                              SqlParameter[] _param = new SqlParameter[]{ .... }

                             IDataParameter[] param = new IDataParameter[ _param.Length ];

                            _param.CopyTo( param, 0 );

 

以上内容出(改)自:IDataParameter