学习笔记-设计实现SqlHelper

一、思维导图

二、知识点
SqlHelper是一个基于.NET Framework的数据库操作组件。组件中包含数据库操作方法，SqlHelper有很多版本，主要以微软一开始发布的SqlHelper类，后面包含进了Enterprise Library开源包中了。还有一个主要版本是dbhelper.org开源的sqlhelper组件，优点是简洁，高性能，不仅仅支持sqlserver，同时支持sqlserver、oracle、access、Mysql数据库，也是一个开源项目，提供免费下载。
三、示例
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using System;using System.Collections.Generic;
using System.Data;
using System.Data.SqlClient;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace H.DAL
{
MySql.Data.MySqlClient;
///
public class SQLHelper
{

    private static string connectionStr = 

System.Configuration.ConfigurationManager.ConnectionStrings[“dbConnection”].ConnectionString;
public SQLHelper() { }
public SQLHelper(string connectionStr)
{
SQLHelper.connectionStr = connectionStr;
}

    public static SqlConnection GetConn()
    {
        SqlConnection sqlconn = null;
        sqlconn = new SqlConnection(connectionStr);
        return sqlconn;
    }

    
    public static DataTable GetDataTable(string sql, params SqlParameter[] sp)
    {
        using (SqlConnection conn = GetConn())
        {
            conn.Open();
            using (SqlDataAdapter sda = new SqlDataAdapter(sql, conn))
            {
                sda.SelectCommand.Parameters.AddRange(sp);
                DataTable dt = new DataTable();
                sda.Fill(dt);
                return dt;
            }
        }
    }
    
    public static int ExecuteNonQuery(string sql, params SqlParameter[] sp)
    {
        using (SqlConnection conn = GetConn())
        {
            conn.Open();
            using (SqlCommand cmd = new SqlCommand(sql, conn))
            {
                cmd.Parameters.AddRange(sp);
                int i = cmd.ExecuteNonQuery();
                return i;
            }
        }

    }

    
    public static object ExecuteScalar(string sql, params SqlParameter[] sp)
    {
        using (SqlConnection conn = GetConn())
        {
            conn.Open();
            using (SqlCommand cmd = new SqlCommand(sql, conn))
            {
                cmd.Parameters.AddRange(sp);
                return cmd.ExecuteScalar();
            }
        }
    }
}

}