Database Connection by Aman Sahani

Add Code

              SqlConnection con = new SqlConnection(@"Data Source=DESKTOP-ADG77QL\SQLEXPRESS;Initial Catalog=studentdb;Integrated Security=True");

            con.Open();

            SqlCommand cnn = new SqlCommand("insert into info_tab values(@studentid,@studentname,@age,@dob,@email,@phone)", con);

            cnn.Parameters.AddWithValue("@Student_Id", int.Parse(textBox1.Text));

            cnn.Parameters.AddWithValue("@Student_Name", textBox2.Text);

            cnn.Parameters.AddWithValue("@Age", int.Parse(textBox3.Text));

            

            cnn.Parameters.AddWithValue("@Dob", DateTime.Parse(textBox4.Text));

            cnn.Parameters.AddWithValue("@Email", textBox5.Text);

            cnn.Parameters.AddWithValue("@Phone", textBox6.Text);

            cnn.ExecuteNonQuery();

            con.Close();

            MessageBox.Show("Record Added Successfully", "Add", MessageBoxButtons.OK, MessageBoxIcon.Information);

           Student_Info Load Code

           SqlConnection con = new SqlConnection(@"Data Source=DESKTOP-ADG77QL\SQLEXPRESS;Initial Catalog=studentdb;Integrated Security=True");

            SqlCommand cnn = new SqlCommand("select * from info_tab", con);

            SqlDataAdapter da = new SqlDataAdapter(cnn);

            DataTable table = new DataTable();

            da.Fill(table);

            dataGridView1.DataSource = table;

         Update Code

         SqlConnection con = new SqlConnection(@"Data Source=DESKTOP-ADG77QL\SQLEXPRESS;Initial Catalog=studentdb;Integrated Security=True");

            con.Open();

            SqlCommand cnn = new SqlCommand("update info_tab set studentname=@studentname,age=@age,dob=@dob,email=@email,phone=@phone where student_id=@student_id", con);

            cnn.Parameters.AddWithValue("@Student_Id", int.Parse(textBox1.Text));

            cnn.Parameters.AddWithValue("@Student_Name", textBox2.Text);

            cnn.Parameters.AddWithValue("@Age", int.Parse(textBox3.Text));

            

            cnn.Parameters.AddWithValue("@Dob", DateTime.Parse(textBox4.Text));

            cnn.Parameters.AddWithValue("@Email", textBox5.Text);

            cnn.Parameters.AddWithValue("@Phone", textBox6.Text);

            cnn.ExecuteNonQuery();

            con.Close();

            MessageBox.Show("Record Updated Successfully", "Update", MessageBoxButtons.OK, MessageBoxIcon.Information);

          Delete Code

          SqlConnection con = new SqlConnection(@"Data Source=DESKTOP-ADG77QL\SQLEXPRESS;Initial Catalog=studentdb;Integrated Security=True");

            con.Open();

            SqlCommand cnn = new SqlCommand("delete info_tab where student_id=@student_id", con);

            cnn.Parameters.AddWithValue("@Student_Id", int.Parse(textBox1.Text));

            

            cnn.ExecuteNonQuery();

            con.Close();

            MessageBox.Show("Record Deleted Successfully", "Delete", MessageBoxButtons.OK, MessageBoxIcon.Information);

Improved code-

using (SqlConnection con = new SqlConnection(@"Data Source=DESKTOP-ADG77QL\SQLEXPRESS;Initial Catalog=studentdb;Integrated Security=True"))

{

    try

    {

        con.Open();

        using (SqlCommand cmd = new SqlCommand("INSERT INTO info_tab VALUES (@studentid, @studentname, @age, @dob, @email, @phone)", con))

        {

            cmd.Parameters.AddWithValue("@studentid", int.Parse(textBox1.Text));

            cmd.Parameters.AddWithValue("@studentname", textBox2.Text);

            cmd.Parameters.AddWithValue("@age", int.Parse(textBox3.Text));

            cmd.Parameters.AddWithValue("@dob", DateTime.Parse(textBox4.Text));

            cmd.Parameters.AddWithValue("@email", textBox5.Text);

            cmd.Parameters.AddWithValue("@phone", textBox6.Text);

            cmd.ExecuteNonQuery();

            MessageBox.Show("Record Added Successfully", "Add", MessageBoxButtons.OK, MessageBoxIcon.Information);

        }

    }

    catch (Exception ex)

    {

        MessageBox.Show("Error: " + ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);

    }

}