Why does database add null values although I am providing data?

Question

I am inserting data in the textbox1 and dropdown1 but the data is only saved in the query which is written at the second position"i.e in this case c_name". C_name is either empty or inserts null values.

protected void Button1_Click(object sender, EventArgs e)
{
    con.Open();
    MySqlCommand cmd = con.CreateCommand();

    cmd.CommandType = CommandType.Text;

    cmd.CommandText = "insert into market (m_name) values ('" + TextBox1.Text + "')";
    cmd.CommandText = "insert into city (c_name) values('" + DropDownList1.SelectedValue + "')";

    if (DropDownList1.SelectedValue == "-1")
    {
        Response.Write("Please select a city");
    }


    cmd.ExecuteNonQuery();
    con.Close();
}

Please use [Parameterized queries](https://stackoverflow.com/questions/7505808/why-do-we-always-prefer-using-parameters-in-sql-statements). — SᴇM, Mar 21 '19 at 05:59
Your code is overwriting the command, the first one is never sent to the server. Not sure if that's your problem but at least it's a line of code that is thrown away and shouldn't be there. Or it should be executed if that's what you want. — Sami Kuhmonen, Mar 21 '19 at 06:04
@SamiKuhmonen what should I do. Please someone write a solution code to this. please — taimoor, Mar 21 '19 at 06:08
You should `ExecuteQuery` for each query you want to execute, not just the last one. — Sami Kuhmonen, Mar 21 '19 at 06:13

score 0 · Accepted Answer · edited Mar 21 '19 at 07:03

You should cmd.ExecuteNonQuery() after the first cmd.CommandText and then you have to do the same for your second cmd.CommandText, and both query will perform their actions.

protected void Button1_Click(object sender, EventArgs e)
{
   if (DropDownList1.SelectedValue == "-1")
   {
       Response.Write("Please select a city");
       return; // Must return don't execute after 'if' part or use 'else' there
   }

   con.Open();
   MySqlCommand cmd = con.CreateCommand();

   cmd.CommandType = CommandType.Text;

   cmd.CommandText = "insert into market (m_name) values ('" + TextBox1.Text + "')";

   cmd.ExecuteNonQuery(); // First insert executed here

   cmd.CommandText = "insert into city (c_name) values('" + DropDownList1.SelectedValue + "')";

   cmd.ExecuteNonQuery(); // Second insert executed here
   con.Close();
}

Why does database add null values although I am providing data?

1 Answers1