sqlHelper

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;

namespace sqlHelper
{
     public static  class SqlHelper
    {
         //string connStr = System.Configuration.ConfigurationManager.ConnectionStrings["connStr"].ConnectionString;
        //获取数据库连接字符串
         private static SqlConnection  GetConn()
         {
             return new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["connStr"].ConnectionString);
         }
         //执行sql语句并返回受影响行数
         public static int ExecuteNoQuery(string sql)
         {
            
             //实现方法一 捕获异常
             //int rows = -1;
             //SqlConnection conn=  GetConn();
             //try
             //{
             //    SqlCommand cmd = new SqlCommand(sql, conn);
             //    conn.Open();
             //    rows = cmd.ExecuteNonQuery();
             //}
             //catch (Exception)
             //{
             //    //正式项目自己定义一个类  对异常进行处理
             //    throw;
             //}
             //finally
             //{
             //conn.Close();
             //conn.Dispose();
             //}
             //return rows;

             //实现方法2 不捕获异常
             //int rows = -1;
             //不捕获异常的写法
             //using (SqlConnection conn=  GetConn())
             //{
             //    SqlCommand cmd = new SqlCommand(sql,conn);
             //    conn.Open();
             //    rows = cmd.ExecuteNonQuery();
             //}
             // return rows;

             //实现方法3直接调用有参数的ExecuteNoQuery  传一个空的参数
            return  ExecuteNoneQuery(sql,null);
         }
         //执行sql语句带参数
         public static int  ExecuteNoneQuery(string sql,params SqlParameter[] param )
         {
             //int rows=-1;
             //using (SqlConnection conn =GetConn())
             //{
             //    SqlCommand cmd = new SqlCommand(sql,conn);
             //    //判断是否有参数
             //    if (param!=null)
             //    {
             //        cmd.Parameters.AddRange(param);
             //    }
             //    conn.Open();
             //    rows = cmd.ExecuteNonQuery();
               
             //}
             //return rows;

             return ExecuteNoneQuery(sql,CommandType.Text,param);
        
         }
         //执行存数过程
         public static  int ExecuteNoneQuery(string sql,CommandType type,params SqlParameter[] param)
         {
            int rows = -1;
             //不捕获异常的写法
             using (SqlConnection conn=  GetConn())
             {
                 SqlCommand cmd = new SqlCommand(sql,conn);
                 cmd.CommandType=type;
                 conn.Open();
                 rows = cmd.ExecuteNonQuery();
             }
              return rows;
         }
         //执行sql语句返回首行首列
         public static object ExecuteScalar(string sql,params SqlParameter[] param)
         {
             object obj = null;
             using (SqlConnection conn=GetConn())
             {
                 SqlCommand cmd = new SqlCommand(sql,conn);
                 cmd.Parameters.AddRange(param);
                 conn.Open();
                 obj = cmd.ExecuteScalar();
             }
             return obj;
         }
         //执行sql语句，返回结果集DataTable
         public static DataTable GetDataTable(string sql ,params SqlParameter [] param)
         {
             DataTable dt = new DataTable();
             using (SqlConnection  conn=GetConn())
             {
                 SqlCommand cmd = new SqlCommand();
                 cmd.Parameters.AddRange(param);
                 SqlDataAdapter adapter = new SqlDataAdapter(cmd);
                 conn.Open();
                 adapter.Fill(dt);
                
             }
             return dt;
         }
       
    }
}