I am confronting a design decision involving null values and I cannot seem to discern which way to go. Therefore, I would like some commentary based on real world experience. The basic issue is episodic duration, expressed as columns named dt_effective_from and dt_superseded_after. Both are datetime types containing values normalized to utc. You see where this is going. The issue is what to enter when the value is known to be unknown, as in some indeterminate future date, which may be never. I read that relational set values should never be null, as null is indeterminate for WHERE clauses and may result in unexpected results. On the other hand, setting some artificially excessive future date seems in its place seems, to me, to have its own problems. Since this issue must have been dealt with time and time again in the past I would like to know what, if any, consensus has been reached on the matter. What is the best way to proceed? -- *** E-Mail is NOT a SECURE channel *** James B. Byrne mailto:ByrneJB@xxxxxxxxxxxxx Harte & Lyne Limited http://www.harte-lyne.ca 9 Brockley Drive vox: +1 905 561 1241 Hamilton, Ontario fax: +1 905 561 0757 Canada L8E 3C3 -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
