Databasen - NULL dates
abuse at cabal.org.uk
Thu Oct 19 12:04:38 BST 2006
On Thu, Oct 19, 2006 at 09:22:32AM +0100, Jacqui Caren wrote:
> Null is correct for this usage however often NULL cannot be indexed and a
That's very much down to the implementation, but in a sane database, you'll
find that you rarely need to look for NULLs for most queries. After all,
"foo = NULL" is always false, so NULL columns can't participate in joins.
You can always use an explicit "foo IS NULL" expression index if it turns
out that you're doing that kind of query regularly.
If you mean that your RDBMS cannot put an index on a column that isn't
marked NOT NULL, I suggest you find something better.
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