简单的sqlhelper的学习日志

一：今天做了一个简单的sqlhelper，还有调用，将今天学的内容总结一下，解决方案如下：

二：对应的sqlhelper的内容：

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

namespace UsersDAL
{
    public  class Class1
    {
        //返回受影响的行数
       // static string constr = "server=.;database=OneDb;uid=sa;pwd=123123";
        string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
        //public  int ExecuteNnonQuery(string sql)
        //{
        //    //string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
        //    using(SqlConnection conn=new SqlConnection(constr))
        //    {
        //        conn.Open();
        //            using(SqlCommand cmd=conn.CreateCommand())
        //            {
        //                cmd.CommandText = sql;
        //                return cmd.ExecuteNonQuery();

        //            }
        //    }
        //}


        public int ExecuteNnonQuery(string sql,params SqlParameter[] parameters)
        {
            //string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
            using (SqlConnection conn = new SqlConnection(constr))
            {
                conn.Open();
                using (SqlCommand cmd = conn.CreateCommand())
                {
                    cmd.CommandText = sql;
                    //foreach(SqlParameter parame in parameters)
                    //{
                    //    cmd.Parameters.Add(parame);
                    //}

                    cmd.Parameters.AddRange(parameters);
                    return cmd.ExecuteNonQuery();

                }
            }
        }


        /// <summary>
        /// 返回首行首列
        /// </summary>
        /// <param name="sql"></param>
        /// <returns></returns>
        public object ExecuteScalar(string sql,params SqlParameter[] parameters)
        {
            using (SqlConnection conn = new SqlConnection(constr))
            {
                conn.Open();
                using (SqlCommand cmd = conn.CreateCommand())
                {
                    cmd.CommandText = sql;
                    cmd.Parameters.AddRange(parameters);
                  return  cmd.ExecuteScalar();
                    
                }
            }
        }
        /// <summary>
        /// 返回一个表
        /// </summary>
        /// <param name="sql"></param>
        /// <returns></returns>
        //public DataTable ExecuteDataTable(string sql,SqlParameter[] parameters)
        //{
        //    using (SqlConnection conn = new SqlConnection(constr))
        //    {
        //        conn.Open();
        //        using (SqlCommand cmd = conn.CreateCommand())
        //        {
        //            cmd.CommandText = sql;
        //            cmd.Parameters.AddRange(parameters);
        //            SqlDataAdapter sda = new SqlDataAdapter(cmd);
        //            DataSet ds = new DataSet();
                    
        //            sda.Fill(ds);
        //            return ds.Tables[0];
        //        }
        //    } 
        //} 
        //使用了长度可变参数
        public DataTable ExecuteDataTable(string sql,params SqlParameter[] parameters)
        {
            using (SqlConnection conn = new SqlConnection(constr))
            {
                conn.Open();
                using (SqlCommand cmd = conn.CreateCommand())
                {
                    cmd.CommandText = sql;
                    cmd.Parameters.AddRange(parameters);
                    SqlDataAdapter sda = new SqlDataAdapter(cmd);
                    DataSet ds = new DataSet();

                    sda.Fill(ds);
                    return ds.Tables[0];
                }
            }
        }   



    }
}