C#工具:Ado.Net SqlServer数据库 MySql数据库

数据库连接字符串(web.config来配置)，可以动态更改connectionString支持多数据库.

SqlServer调用数据库

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

namespace Dal
{
    public static class DBHelper
    {
        public static string strCon = "Data Source=.;Initial Catalog=Week3;Integrated Security=True";
        /// <summary>
        /// 增删改
        /// </summary>
        /// <param name="sql">sql语句</param>
        /// <param name="str">连接字符串</param>
        /// <returns></returns>
        public static int ExecuteNonQuery(string sql)
        {
            //实例化连接对象
            SqlConnection conn = new SqlConnection(strCon);
            int result = 0;
            try
            {
                conn.Open();
                //实例化命令对象
                SqlCommand cmd = new SqlCommand(sql, conn);
                //执行命令
                result = cmd.ExecuteNonQuery();
            }
            catch (Exception)
            {

                throw;
            }
            finally
            {
                conn.Close();
            }
            return result;
        }
        /// <summary>
        /// 获取表格
        /// </summary>
        /// <param name="sql">sql语句</param>
        /// <param name="str">连接字符串</param>
        /// <returns></returns>
        public static DataTable GetDataTable(string sql)
        {
            //实例化连接对象
            SqlConnection conn = new SqlConnection(strCon);
            DataTable dt = new DataTable();

            try
            {
                //实例化适配器
                SqlDataAdapter sda = new SqlDataAdapter(sql, conn);
                sda.Fill(dt);

            }
            catch (Exception)
            {

                throw;
            }
            return dt;
        }
        /// <summary>
        /// 
        /// </summary>
        /// <param name="sql">sql语句</param>
        /// <param name="str">连接字符串</param>
        /// <returns></returns>
        public static SqlDataReader GetDataReader(string sql)
        {
            //实例化连接对象
            SqlConnection conn = new SqlConnection(strCon);
            SqlDataReader sdr;
            try
            {
                conn.Open();
                //实例化命令对象
                SqlCommand cmd = new SqlCommand(sql, conn);
                sdr = cmd.ExecuteReader();

            }
            catch (Exception)
            {

                throw;
            }
            return sdr;
        }
        /// <summary>
        /// 返回单行单列
        /// </summary>
        /// <param name="sql">sql语句</param>
        /// <param name="str">连接字符串</param>
        /// <returns></returns>
        public static int ExecuteScalar(string sql)
        {
            //实例化连接对象
            SqlConnection conn = new SqlConnection(strCon);
            int result = 0;
            try
            {
                conn.Open();
                //实例化命令对象
                SqlCommand cmd = new SqlCommand(sql, conn);
                result = Convert.ToInt32(cmd.ExecuteScalar());
            }
            catch (Exception)
            {

                throw;
            }
            finally
            {

                conn.Close();
            }
            return result;
        }



        /// <summary>
        /// 信息分页显示
        /// </summary>
        /// <returns></returns>
        public static DataTable GetInfoByPage(int Pageindex, int PageSize)
        {
            string sql = string.Format(@"select top {0}* from(
                    select XinXi.*,ROW_NUMBER() over(order by XinXi.XinXiId) pid ,Type.Name from Type 
                    inner join XinXi on Type.Id= XinXi.TypeId ) as temp 
                    where temp.pid>{1}", PageSize, (Pageindex - 1) * PageSize);
            return DBHelper.GetDataTable(sql);
        }
        /// <summary>
        /// 获取个数
        /// </summary>
        /// <returns></returns>
        public static int GetCount()
        {
            string sql = "select count(XinXi.XinXiId) from Type   inner join XinXi on Type.Id= XinXi.TypeId";
            return DBHelper.ExecuteScalar(sql);

        }
    }
}

SqlServer-DBHelper