自己封装的ASP.NET的SQLITE数据库的操作类

/*
 * 作者: 牛腩
 * 创建时间: 2010-1-20 10:43:14
 * Email: 164423073@qq.com
 * 说明: 对SQLite数据库的增删查改操作的封装类
  */


using  System;
using  System.Collections.Generic;
using  System.Linq;
using  System.Text;
using  System.Data;
using  System.Data.SQLite;
using  System.Web.Configuration;
using  System.Web;


namespace  Niunan.Tg029.Hr.Utility
{
     public   class  SQLiteHelper
    {
         private  SQLiteConnection conn  =   null ;
         private  SQLiteCommand cmd  =   null ;
         private  SQLiteDataReader sdr  =   null ;


         public  SQLiteHelper()
        {
            // string connStr = WebConfigurationManager.ConnectionStrings["connStr"].ToString();
             string  connStr  =   " Data Source= "   +  HttpContext.Current.Server.MapPath( " ~/test/test.sqlite " ) ;
            conn  =   new  SQLiteConnection(connStr);
        }


         ///   <summary> 创建Command对象
         ///  
         ///   </summary>
         ///   <param name="sql"> SQL语句 </param>
         public   void  CreateCommand( string  sql) {
            conn.Open();
            cmd  =   new  SQLiteCommand(sql, conn);        
        }


         ///   <summary> 添加参数
         ///  
         ///   </summary>
         ///   <param name="paramName"> 参数名称 </param>
         ///   <param name="value"> 值 </param>
         public   void  AddParameter( string  paramName, object  value) {
            cmd.Parameters.Add( new  SQLiteParameter(paramName,value));
        }


         ///   <summary> 执行不带参数的增删改SQL语句
         ///   
         ///   </summary>
         ///   <param name="cmdText"> 增删改SQL语句 </param>
         ///   <param name="ct"> 命令类型 </param>
         ///   <returns></returns>
         public   bool  ExecuteNonQuery()
        {
             int  res;
             try
            {
                res  =  cmd.ExecuteNonQuery();
                 if  (res  >   0 )
                {
                     return   true ;
                }
            }
             catch  (Exception ex)
            {
                 throw  ex;
            }
             finally
            {
                 if  (conn.State  ==  ConnectionState.Open)
                {
                    conn.Close();
                }
            }
             return   false ;
        }


         ///   <summary> 执行查询SQL语句
         ///   
         ///   </summary>
         ///   <param name="cmdText"> 查询SQL语句 </param>
         ///   <returns></returns>
         public  DataTable ExecuteQuery()
        {
            DataTable dt  =   new  DataTable();
             using  (sdr  =  cmd.ExecuteReader(CommandBehavior.CloseConnection))
            {
                dt.Load(sdr);
            }
             return  dt;
        }


         ///   <summary> 返回查询SQL语句查询出的结果的第一行第一列的值
         ///  
         ///   </summary>
         ///   <returns></returns>
         public   string  ExecuteScalar()
        {
             string  res  =   "" ;
             try
            {
                 object  obj  =  cmd.ExecuteScalar();
                 if  (obj  !=   null )
                {
                    res  =  obj.ToString();
                }
            }
             catch  (Exception ex)
            {
                 throw  ex;
            }
             finally
            {
                 if  (conn.State  ==  ConnectionState.Open)
                {
                    conn.Close();
                }
            }
             return  res;
        }


    }
}