C#_JDBC连接数据库

  1 using System;
  2 using System.Collections.Generic;
  3 using System.Linq;
  4 using System.Text;
  5 using System.Threading.Tasks;
  6 using System.Data.SqlClient;
  7 using System.Data;
  8 
  9 namespace MySchool.DAL
 10 {
 11     public class DBHelper
 12     {
 13         //private const string conn = "Data Source=.;Initial Catalog=MySchool;User ;
 14         private const string conn = "Data Source=.;Initial Catalog=MySchool;User ;
 15         private static SqlConnection connection = new SqlConnection(conn);
 16 
 17 
 18         /// <summary>
 19         /// 读取数据
 20         /// </summary>
 21         /// <returns></returns>
 22         public static SqlDataReader Reader(string sql)
 23         {
 24             try
 25             {
 26                 connection.Open();
 27                 SqlCommand comm = new SqlCommand(sql, connection);
 28                 return comm.ExecuteReader(CommandBehavior.CloseConnection);
 29             }
 30             catch (Exception ex)
 31             {
 32                 throw;
 33             }
 34         }
 35 
 36         /// <summary>
 37         /// 增删改数据
 38         /// </summary>
 39         /// <param name="sql"></param>
 40         /// <returns></returns>
 41         public static int ExecuteNonQuery(string sql)
 42         {
 43             try
 44             {
 45                 connection.Open();   //打开数据库连接
 46                 SqlCommand comm = new SqlCommand(sql, connection);
 47                 return comm.ExecuteNonQuery();
 48             }
 49             catch (Exception ex)
 50             {
 51                 throw;
 52             }
 53             finally
 54             {
 55                 connection.Close();
 56             }
 57         }
 58         /// <summary>
 59         /// 返回单个值
 60         /// </summary>
 61         /// <param name="sql"></param>
 62         /// <returns></returns>
 63         public static object ExecuteScalar(string sql)
 64         {
 65             try
 66             {
 67                 connection.Open();   //打开数据库连接
 68                 SqlCommand comm = new SqlCommand(sql, connection);
 69                 return comm.ExecuteScalar();
 70 
 71             }
 72             catch (Exception)
 73             {
 74                 throw;
 75             }
 76             finally
 77             {
 78                 connection.Close();
 79             }
 80         }
 81         /// <summary>
 82         /// 返回数据集
 83         /// </summary>
 84         /// <param name="sql"></param>
 85         /// <param name="tableName"></param>
 86         /// <returns></returns>
 87         public static DataSet Fill(string sql, string tableName)
 88         {
 89             try
 90             {
 91                 connection.Open();  //打开连接
 92                 //创建数据适配器对象
 93                 SqlDataAdapter sda = new SqlDataAdapter(sql, connection);
 94                 //创建数据集
 95                 DataSet ds = new DataSet();
 96                 sda.Fill(ds, tableName); //填充数据集
 97                 return ds;
 98             }
 99             catch (Exception ex)
100             {
101                 throw;
102                 //将异常引发出现
103                 //  throw new Exception(e.Message);
104             }
105             finally
106             {
107                 connection.Close();
108             }
109         }
110     }
111 }