如果表单字段为空，则将替代值插入到mysql数据库中

Question

The following form collects data about the color preference of the visitors.

how to insert a predefined alternative value into mysql database if the users submit the blank form.

the thing is to consider here is i don't want to prevent user from submitting the blank form using form validation.

my present backend codes are as following:

if ((isset($_POST["MM_insert"])) && ($_POST["MM_insert"] == "form1")) {
  $insertSQL = sprintf("INSERT INTO users (color_name) VALUES (%s)",


   GetSQLValueString($_POST['color_name'], "text")),

  mysql_select_db($database_x, $x);
  $Result1 = mysql_query($insertSQL, $x) or die(mysql_error());

  $insertGoTo = "choicecolor.php";
  if (isset($_SERVER['QUERY_STRING'])) {
    $insertGoTo .= (strpos($insertGoTo, '?')) ? "" : "?";
    $insertGoTo .= $_SERVER['QUERY_STRING'];
  }

---

<form action="<?php echo $editFormAction; ?>" method="post" name="form1" id="form1">
<table align="center">
  <tr valign="baseline">
    <td align="right" nowrap="nowrap">Enter Color Name:</td>
    <td><input type="text" name="color_name" value="" size="32" /></td>
  </tr>
   <tr valign="baseline">
    <td nowrap="nowrap" align="right"><input type="hidden" name="MM_insert" value="form1" /></td>
                    <td>
                    <input type="submit" value="Submit Color Name" />
                    </td>
                  </tr>
                </table>
              </form>
              </td>
            </tr>
      </table>
</form>

if the visitors submit a blank form without entering any value, a predefined value (for example, "no choice") shall be inserted into database and if the visitors submit a filled form with the inputted value "yellow", the value "yellow", shall be inserted into database.

how to predefine the value in this case using PHP?

Answer 1

to do this in php add something like this

$toInsert = isset($_POST['color_name'])? $_POST['color_name']: 'Your default string';

and then alter this line

$insertSQL = sprintf("INSERT INTO users (color_name) VALUES (%s)", GetSQLValueString($_POST['color_name'], "text"));

to this

$insertSQL = sprintf("INSERT INTO users (color_name) VALUES (%s)", GetSQLValueString($toInsert, "text"));

but you should really be looking at PDO etc first. Also as Dark Wish mentioned it might be better to do this at the database level rather than with php.