参考上一篇:数据库连接配置app.config
写一个通用的数据库访问类。
public class SqlHelper //数据库连接类
{
//获取数据库连接字符串,其属于静态变量且只读,项目中所有文档可以直接使用,但不能修改
public static readonly string connectString = ConfigurationManager.ConnectionStrings["CoonStr"].ConnectionString;
//负责查询 ,二个参数(sql查询语句,参数)
public static DataTable ExecuteDataTable(string sql, params SqlParameter[] parameters)
{
DataTable dt = new DataTable();
using (SqlConnection con = new SqlConnection(connectString))
{
SqlDataAdapter adapter = new SqlDataAdapter(sql, con);
adapter.SelectCommand.Parameters.AddRange(parameters);
adapter.Fill(dt);
}
return dt;
}
之后调用的时候:
//查找 歌名、歌手名、路径
string sql = "select sname,sername,spath from songs,singers where songs.Serid=Singers.Serid and Singers.Serid=@id";
DataTable dt=SqlHelper .ExecuteDataTable (sql ,new SqlParameter("@id",singer.serid ));
或者
//拼连接字符串
string sql = "select * from Users where Uname=@name";
DataTable dt = SqlHelper.ExecuteDataTable(sql, new SqlParameter("@name", strName));
//从数据库中 查找的一组数据
//负责增删改
public static int ExecuteNonQuery(string sql, params SqlParameter[] parameters)
{
using (SqlConnection con = new SqlConnection(connectString))
{
using (SqlCommand cmd = new SqlCommand(sql, con))
{
con.Open();
cmd.Parameters.AddRange(parameters);
return cmd.ExecuteNonQuery();
}
}
}
//之后调用的时候:
//拼接查询语句
string sql = "Insert into Users(Uname,Upwd,Ubrith) values (" +"'"+Uname+"','"+Upwd+"','"+Ubrith+"')" ;
DAL.SqlHelper.ExecuteNonQuery(sql);
MessageBox.Show("增加会员成功");