Martijn Tonies wrote:

>>>Then what is a "blank date"?
>>
>>Something like NOT NULL but not filled either <g>. In VFP we represent it
>>with {} or { / / }
>>
>>Actually what happens is when a date is optional like: Please enter you
>>birth date (optional)? People may not want to reveal the date and would
>>like to keep it empty.
>
> In this case, the birth-date is "unknown", in other words: NULL.
>
> An empty string ( '' ) does exist, but an empty date doesn't, unless
> you choose the/a zero-date, eg: 1/1/1899 or so.

Just to elaborate - Firebird stores dates (and times) as numbers so we
can simply add or subtract dates to get durations. So either you put in
'0' ( 1/1/1899 ) or you leave it NULL. I use '0' and flag that as not set.
The thing to note here is genealogical data can't be stored in a date
field, so you end up having to use a character field for that!

--
Lester Caine
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L.S.Caine Electronic Services