Test if a field is nullable (PHP 4 >= 4.0.2, PHP 5 <= 5.0.4)
bool ingres_field_nullable ( int index [, resource link] )

ingres_field_nullable() returns TRUE if the field can be set to the NULL value and FALSE if it can't.

index is the number of the field and must be between 1 and the value given by ingres_num_fields().

See also ingres_query(), ingres_fetch_array(), ingres_fetch_object(), and ingres_fetch_row().