On 21/07/10 15:08, Prometheus Prometheus wrote: > head -> wall
That's about how I feel about SQL NULLs in general. They seem like a great idea. A way of representing "unknown" or "undefined" in a generic, consistent manner. Or is that "a definite value that means empty or absent" ? Depends on who you ask, which is the first problem. Then you get to combining them with anything else in any way. Comparing row-types or arrays with null entries. Uniqueness. Aggregation/counting. Conceptual mismatches with the null concept in other languages, where null/None/nil/undef means "the certain value of nothing or emptiness" rather than "could be anything or nothing, I dunno" as it does in SQL. SQL NULL's contradictions often remind me of early formulations of set theory and their ... issues. http://en.wikipedia.org/wiki/Russell%27s_paradox -- Craig Ringer Tech-related writing: http://soapyfrogs.blogspot.com/ -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
