C#链接数据库的三部曲

 static void Main(string[] args)
        {
            int resLine = 0;
            //连接字符串
            string temp = @"ZZ-NBPC0003AMSSQLSERVER";
            string str = "Data Source=" + temp + ";Initial Catalog=dbtest;Integrated Security=True;";
            using (SqlConnection sqlConn = new SqlConnection(str))      //1.建立连接
            {
                //string sql = "select * from test update test set cTitle='数学' where CID BETWEEN 17 AND 20";
                string sql = "select * from test update test set cTitle='英语' where CID<5";
                string sql1 = "select COUNT(*) from test";
                string sql2 = "select * from test";
                using (SqlCommand cmd = new SqlCommand(sql, sqlConn))  //2.创建Command对象
                {

                    sqlConn.Open();                                    //3.打开并执行

                    resLine = cmd.ExecuteNonQuery();
                    //SqlDataReader srd = cmd.ExecuteReader();   //insert/delete/update

                    //cmd.ExecuteReader();// 查询多行多列的时候    默认情况下独占一个sqlConn连接对象

                    //cmd.ExecuteScalar();//返回单个结果

                    //cmd.Dispose();

                }