SqlConnection konek;
SqlDataAdapter sikwelDataAdapter = new SqlDataAdapter();
public DataTable tableResult = new DataTable();
SqlCommand query;
string connString=@"Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\Kink0821.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True";

//My code in connection to database
konek = new SqlConnection(connString);
konek.Open();

//one of my code to search in my database
                    tableResult = new DataTable();
                    sikwelDataAdapter = new SqlDataAdapter("select * from Temp_custTable", konek);
                    sikwelDataAdapter.Fill(tableResult);
                    dataGridView1.DataSource = tableResult;
                    tableResult.Dispose();
                    tableResult = new DataTable();
                    sikwelDataAdapter = new SqlDataAdapter("select * from Temp_cakeTable", konek);
                    sikwelDataAdapter.Fill(tableResult);
                    dataGridView2.DataSource = tableResult;
//this time,i used"Dispose()" & "tableResult = new DataTable()" twice.Is that necessary?am i Doing that right?

//in one of my button click event handler..
query = new SqlCommand("DELETE from Temp_cakeTable", konek);
query.CommandType = CommandType.Text;
query.ExecuteNonQuery();
dataGridView2.Refresh();
//the dataGridView is not displaying the changes I made

 
SqlConnection cn = new SqlConnection(MyProject.Properties.Settings.Default.ConnectionString);
SqlCommand cmd = new SqlCommand();
cmd.Connection = cn;
cmd.CommandText="your sql statement or the stored procedure name";
 
// if using a stored procedure
cmd.CommandType = CommandType.StoredProcedure;
// if using an sql command
cmd.CommandType = CommandType.Text;
 
cn.Open();
// if you are simply adding/modifying something on the database without returning anything
cn.ExecuteNonQuery();
cn.Close();

string name, address, phone;
cmd.Open();
SqlDataReader dr = cmd.Execute Reader();
 
while (dr.Read())
{
//assuming Name, Address and Phone are the fields of a table.
name = dr["Name"].ToString();
address = dr["Address"].ToString();
phone = dr["Phone"].ToString();
}
cn.close();

SqlConnection con = new SqlConnection("server=.;database=Emp;uid=sa;pwd=sa");
        con.Open();
        SqlCommand cmd = new SqlCommand("Update emp set=Emp_Id where Emp_Name,Emp_Address,Emp_Sal", con);
        //cmd.CommandType = CommandType.StoredProcedure;
 
        cmd.Parameters.Add(new SqlParameter ("@name",SqlDbType.NVarChar,50));
        cmd.Parameters["@name"].Value =TextBox2.Text;
 
        cmd.Parameters.Add(new SqlParameter("@add", SqlDbType.NVarChar,50));
        cmd.Parameters["@add"].Value = TextBox3.Text;
 
        cmd.Parameters.Add(new SqlParameter("@sal", SqlDbType.Money,8));
        cmd.Parameters["@sal"].Value = TextBox4.Text;
        cmd.ExecuteNonQuery();
        Response.Write("Record Updated");
        con.Close();