Update the data in the MySQL database said successful but does not update

I'm having an issue updating my SQL database, it says successful but does not update the field in the database

// update data in mysql database
$sql="UPDATE Triage SET Forename='$Forename', surname='$surname', DOB='$DOB' WHERE Reference='$Reference'";
$result=mysql_query($sql);

Any ideas?

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Just try this code:

// update data in mysql database
$sql="UPDATE Triage SET Forename='".$Forename."', surname='".$surname."', DOB='".$DOB."' WHERE Reference='".$Reference."'";
$result=mysql_query($sql);`