Subject Re: Table level From Ronnie MacGregor <No_Sp@m.Thanks> Date Sun, 30 Sep 2018 12:50:00 +0100 Newsgroups dbase.getting-started In article <PpvS8x#VUHA.1828@ip-AC1E04A7>, dbase@nospam.goldenstag.net says... > logical fields will default to false But this is not a good thing, because it looks as if we know for sure that the value of this field is false. A logical field hsa three states, true, false, and unknown or undetermined. This is really important. Real world example . . . We have a logical field which indicates whether or not a Patient is Diabetic. If we have used autonullfields to default to false, then it looks as if we know that this Patient is not Diabetic, when in fact we don't know. In a MySQL table, we use a one character long character field for logical purposes. This single character field can contain "T", "F", or "U" or NULL A field value of NULL means that a user has never saved data to this field, and is therefore treated as "U" - Unknown. In some cases we this field defaulting to "U" on the creation of a new record. For display purposes, the content of this type of field is often morphed : T - "True" or "Yes" F - "False" or "No" U - "Unknown" or "Undetermined" NULL - "Unknown" or "Undetermined" Now I need to go and do something useful !! -- Ronnie MacGregor Scotland Ronnie at dBASEdeveloper dot co dot uk www.dBASEdeveloper.co.uk