oci_field_is_null() returns TRUE if field field from the statement is NULL. Parameter field could be a field's index or a field's name (uppercased).
Nota: In PHP versions before 5.0.0 you must use ocicolumnisnull() instead. This name still can be used, it was left as alias of oci_field_is_null() for downwards compatability. This, however, is deprecated and not recommended.