C#数据库操作问题
SqlConnection con = new SqlConnection("server = .;database = zperp;uid= sa ;pwd = 44944");
con.Open();
string a = "0309";
SqlCommand cmd = new SqlCommand("select fname from t_hrempl where fempno = '"+ a +"'",con);
SqlDataAdapter sda = new SqlDataAdapter(cmd);
DataSet ds = new DataSet();
sda.Fill(ds,"t_hrempl");
string fempname = ds.Tables["fname"].ToString();
con.Close();
MessageBox.Show(fempname);
请问那里有问题?