数据库封装方法

C#数据库封装方法

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

namespace ADONET2
{
class SqlHelper
{
private static string connStr = ConfigurationManager.ConnectionStrings["dbConnStr"].ConnectionString;

//封装方法的原则：把不变的放到方法里，把变化的放到参数中

////public static int ExecuteNonQuery(string sql)
////{
//// using (SqlConnection conn = new SqlConnection(connStr))
//// {
//// conn.Open();
//// using (SqlCommand cmd = conn.CreateCommand())
//// {
//// cmd.CommandText = sql;
//// return cmd.ExecuteNonQuery();
//// }
//// }
////}

////public static object ExecuteScalar(string sql)
////{
//// using (SqlConnection conn = new SqlConnection(connStr))
//// {
//// conn.Open();
//// using (SqlCommand cmd = conn.CreateCommand())
//// {
//// cmd.CommandText = sql;
//// return cmd.ExecuteScalar();
//// }
//// }
////}

//////只用来执行查询结果比较少的sql
////public static DataTable ExecuteDataTable(string sql)
////{
//// using (SqlConnection conn = new SqlConnection(connStr))
//// {
//// conn.Open();
//// using (SqlCommand cmd = conn.CreateCommand())
//// {
//// cmd.CommandText = sql;
//// SqlDataAdapter adapter = new SqlDataAdapter(cmd);
//// DataSet dataset = new DataSet();
//// adapter.Fill(dataset);
//// return dataset.Tables[0];
//// }
//// }
////}

//第二版

//public static int ExecuteNonQuery(string sql,SqlParameter[] parameters)
//{
// using (SqlConnection conn = new SqlConnection(connStr))
// {
// conn.Open();
// using (SqlCommand cmd = conn.CreateCommand())
// {
// cmd.CommandText = sql;
// //foreach (SqlParameter param in parameters)
// //{
// // cmd.Parameters.Add(param);
// //}
// cmd.Parameters.AddRange(parameters);
// return cmd.ExecuteNonQuery();
// }
// }
//}

//public static object ExecuteScalar(string sql,SqlParameter[] parameters)
//{
// using (SqlConnection conn = new SqlConnection(connStr))
// {
// conn.Open();
// using (SqlCommand cmd =

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