The tcpdf file that causes the "data has already been output" is in the tcpdf folder called tcpdf.php. You can modify it:
add the line ob_end_clean(); as below (3rd last line):
public function Output($name='doc.pdf', $dest='I') {
//LOTS OF CODE HERE....}
switch($dest) {
case 'I': {
// Send PDF to the standard output
if (ob_get_contents()) {
$this->Error('Some data has already been output, can\'t send PDF file');}
//some code here....}
case 'D': { // download PDF as file
if (ob_get_contents()) {
$this->Error('Some data has already been output, can\'t send PDF file');}
break;}
case 'F':
case 'FI':
case 'FD': {
// save PDF to a local file
//LOTS OF CODE HERE..... break;}
case 'E': {
// return PDF as base64 mime email attachment)
case 'S': {
// returns PDF as a string
return $this->getBuffer();
}
default: {
$this->Error('Incorrect output destination: '.$dest);
}
}
ob_end_clean(); //add this line here
return '';
}
Now lets look at your code.
I see you have $rs and $sql mixed up. These are 2 different things working together.
$conn=odbc_connect('northwind','****','*****');
if (!$conn) {
exit("Connection Failed: " . $conn);
}
$sql="SELECT * FROM products"; //is products your table name?
$rs=odbc_exec($conn,$sql);
if (!$rs) {
exit("Error in SQL");
}
while (odbc_fetch_row($rs)) {
$prodname=odbc_result($rs,"Product Name"); //but preferably never use spaces for table names.
$prodid=odbc_result($rs,"ProdID"); //prodID is assumed attribute
echo "$prodname";
echo "$prodid";
}
odbc_close($conn);
now you can use the $prodname and output it to the TCPDF output.
and I assume your are connecting to a MS access database.