Deleting MySQL data
The basic principle of deletion is a two-step process: first, identify the row or rows to be deleted; and second, remove the data with an SQL DELETE statement.As in an update, the first step requires a key value be provided, and any technique described for capturing keys in updates can be used. We assume here that a unique, primary key value for the row to be deleted is available.
Deleting rows using a primary key value is a minor modification to the update functionality of the script in Example 6-8. For example, the following fragment creates and runs a query to delete a specified customer identified by the value of $custID:
Deleting MySQL Rows
// Connect to the database, clean, and validate data
// We have a custID. Set up a delete query
$query = "DELETE FROM customer
WHERE cust_id = $custID";
if ( (@ mysql_query ($query, $connection))
&& @ mysql_affected_rows( ) == 1)
{
// Query ran ok
// Relocate to the receipt page with status=T
header("Location: " .
"delete_receipt.php?" .
"cust_id=$custID" .
"&status=T");
}
else
{
// Failed to delete customer row.
// Relocate to the status page with status=F
header("Location: " .
"delete_receipt.php?" .
"status=F");
}