Pick style databases have historically used the term "null" to mean an empty
(zero length) character string. When SQL support was added, the developers
of UniVerse (etc) were faced with a problem of terminology as SQL uses the
term null to mean "has no value".

The distinction between Pick null and SQL null is always an exciting one to
try to explain to novice users. Pick null is explicitly empty whereas SQL
null has no value. In my experience, not very many multivalue applications
actually use the SQL null concept.

In UV, SQL null is represented by putting a special, configurable value in
the data field, usually char(128). This is recognised by the query processor
and some program constructs.

Any use of the term null in the UV world generally has then Pick meaning
unless you make it clear you are talking about SQL null. Hence, the original
posting that raised this thread was absolutely right; a null field is an
empty string.


Martin Phillips
Ladybridge Systems
17b Coldstream Lane, Hardingstone, Northampton NN4 6DB
+44-(0)1604-709200
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