delete first raw when final data is entered

sisira

hello,

freinds, i am inserting data to a tadabase using a simple form. What i want is to limit my data in the data base to 100. That is wen i insert the 101 data item, i want to delete the 1st data item in the data base too.

Is it possible to do?how can i do this?

this is my page coding

<?php require_once('../Connections/AAAA.php'); ?>
<?php
function GetSQLValueString($theValue, $theType, $theDefinedValue = "", $theNotDefinedValue = "") 
{
  $theValue = (!get_magic_quotes_gpc()) ? addslashes($theValue) : $theValue;

  switch ($theType) {
    case "text":
      $theValue = ($theValue != "") ? "'" . $theValue . "'" : "NULL";
      break;    

    case "long":
    case "int":
      $theValue = ($theValue != "") ? intval($theValue) : "NULL";
      break;
    case "double":
      $theValue = ($theValue != "") ? "'" . doubleval($theValue) . "'" : "NULL";
      break;
    case "date":
      $theValue = ($theValue != "") ? "'" . $theValue . "'" : "NULL";
      break;
    case "defined":
      $theValue = ($theValue != "") ? $theDefinedValue : $theNotDefinedValue;
      break;
  }
  return $theValue;
}

$editFormAction = $_SERVER['PHP_SELF'];
if (isset($_SERVER['QUERY_STRING'])) {
  $editFormAction .= "?" . htmlentities($_SERVER['QUERY_STRING']);
}

if ((isset($_POST["MM_insert"])) && ($_POST["MM_insert"] == "form1")) {
  $insertSQL = sprintf("INSERT INTO employees (email) VALUES (%s)",
                       GetSQLValueString($_POST['email'], "text"));

  mysql_select_db($database_chat, $chat);
  $Result1 = mysql_query($insertSQL, $chat) or die(mysql_error());

  $insertGoTo = "3.php";
  if (isset($_SERVER['QUERY_STRING'])) {
    $insertGoTo .= (strpos($insertGoTo, '?')) ? "&" : "?";
    $insertGoTo .= $_SERVER['QUERY_STRING'];
  }
  header(sprintf("Location: %s", $insertGoTo));
}
?>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>Untitled Document</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<script language="JavaScript" type="text/JavaScript">
<!--
function MM_reloadPage(init) {  //reloads the window if Nav4 resized
  if (init==true) with (navigator) {if ((appName=="Netscape")&&(parseInt(appVersion)==4)) {
    document.MM_pgW=innerWidth; document.MM_pgH=innerHeight; onresize=MM_reloadPage; }}
  else if (innerWidth!=document.MM_pgW || innerHeight!=document.MM_pgH) location.reload();
}
MM_reloadPage(true);
//-->
</script>
</head>

<body>
<div id="Layer1" style="position:absolute; width:514px; height:115px; z-index:1">
  <form name="form1" method="POST" action="<?php echo $editFormAction; ?>">
    <table width="100%"  border="0">
      <tr>
        <td> email </td>
        <td><input name="email" type="text" id="email"></td>
      </tr>
      <tr>
        <td>&nbsp;</td>
        <td>&nbsp;</td>
      </tr>
      <tr>
        <td>&nbsp;</td>
        <td><input type="submit" name="Submit" value="Submit"></td>
      </tr>
      <tr>
        <td>&nbsp;</td>
        <td>&nbsp;</td>
      </tr>
    </table>
  <input type="hidden" name="MM_insert" value="form1">
  </form>
  <p>&nbsp;</p>
</div>
</body>
</html>

paulnf

yes its possible, what i would do is do a record count and then delete the last record prior to entering the next entry.

this would be my mock psuedocode.

$sql = mysql_query("SELECT <field> FROM <table>") or die(mysql_error());
$count = mysql_num_rows($sql);

if($count > 100){
delete the oldest recordset:
insert new recordset;
}else{
insert new recordset;
}

laserlight

It would be better to do this with database triggers.

paulnf

not familiar with that. I'll have to look that up. good point

sisira

thanks freinds,

so as you i entered the coding to delete the 100th row. But when submiting the form an eror appears as,
" Parse error: parse error, unexpected T_STRING in /AA/another4/test/5.php on line 46
"
lie 46 is
"delete the oldest recordset:"

so where might have i gone wrong?

thanks pals
sisira

this is my page coding

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>Untitled Document</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<script language="JavaScript" type="text/JavaScript">
<!--
function MM_reloadPage(init) {  //reloads the window if Nav4 resized
  if (init==true) with (navigator) {if ((appName=="Netscape")&&(parseInt(appVersion)==4)) {
    document.MM_pgW=innerWidth; document.MM_pgH=innerHeight; onresize=MM_reloadPage; }}
  else if (innerWidth!=document.MM_pgW || innerHeight!=document.MM_pgH) location.reload();
}
MM_reloadPage(true);
//-->
</script>
</head>

<body>
<div id="Layer1" style="position:absolute; width:606px; height:115px; z-index:1; left: 42px;">
  <form name="form1" method="post" action="5.php">
    <table width="100%"  border="0">
      <tr>
        <td width="17%">email</td>
        <td width="83%"><input name="email" type="text" id="email"></td>
      </tr>
      <tr>
        <td>&nbsp;</td>
        <td><input type="submit" name="Submit" value="Submit"></td>
      </tr>
    </table>
  </form>
</div>

   <?php  

//This gets all the other information from the form 
$email=$_POST['email']; 

// Connects to your Database 
mysql_connect("XXXX", "XXXX", "XXXX") or die(mysql_error()) ; 
mysql_select_db("XXXX") or die(mysql_error()) ; 

//Select the field from the table to delete. "no" is a auto incremental primary key
$sql = mysql_query("SELECT 'no' FROM 'employees'") or die(mysql_error());
$count = mysql_num_rows($sql);

//Delete The Last (100th) row
if($count > 100){
delete the oldest recordset:
insert new recordset;
}else{
insert new recordset;
}


 //Writes the information to the database 
mysql_query("INSERT INTO `employees` VALUES ('', '', '$email')") ;  ?>


</body>
</html>

dagon

delete the oldest recordset:

is not valid php, paulnf was giving you the basic idea, you need to fill in those lines your self.