[Tfug] "Ordering" tuples in a table

[Zack Williams]

> So, how do you do this?  Consider a record for a
> "person" having fields that specify name, birthdate, etc.
> In addition, fields that REFERENCE *other* records
> defining the "mother" and "father" for that "person".
> I.e., how do you refer to a mother who's record doesn't
> yet exist??

Special value in the field, such as blank or -1.  Special case for
this in code.

- Zack