[C++] C#三层架构第五课之DBUtil层设计

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Data;
using System.Data.SqlClient;
namespace DbUtil
{
  public class DBHelper
  {
    //增删改:可以封装到一个方法;
    /// <summary>
    /// 
    /// </summary>
    /// <param name="sql">sql语句，insert update delte</param>
    /// <param name="parameters">list：集合；动态添加数据；长度不固定</param>
    /// <returns></returns>
    public static bool update(String sql,List<SqlParameter>parameters) {
      String url = "server=.;database=MyDb;uid=sa;pwd=123456";
      //1.链接对象;
      SqlConnection conn = new SqlConnection(url);
      conn.Open();
      //2.SqlCommand
      SqlCommand cmd = conn.CreateCommand();
      cmd.CommandText = sql;
      if (parameters != null)
      {
        //继续添加参数;
        for (int i = 0; i < parameters.Count; i++)
        {
          cmd.Parameters.Add(parameters[i]);
        }
      }
      int result=cmd.ExecuteNonQuery();
      if (result > 0) 
        return true;
      return false;
    }
    public static DataTable query(String sql, List<SqlParameter> parameters)
    {
      String url = "server=.;database=MyDb;uid=sa;pwd=123456";
      //1.链接对象;
      SqlConnection conn = new SqlConnection(url);
      conn.Open();
      //2.SqlCommand
      SqlCommand cmd = conn.CreateCommand();
      cmd.CommandText = sql;
      if (parameters != null)
      {
        //继续添加参数;
        for (int i = 0; i < parameters.Count; i++)
        {
          cmd.Parameters.Add(parameters[i]);
        }
      }
      SqlDataAdapter da = new SqlDataAdapter(cmd);
      DataTable dt=new DataTable();
      da.Fill(dt);
      return dt;
    }
  }
}