On Sun, Aug 9, 2009 at 5:19 PM, Tom Lane<t...@sss.pgh.pa.us> wrote: > >> I am having a hard time wrapping my brain around what it means to have >> multiple, incompatible notions of equality... any help appreciated! > > Well, for instance a complex-number datatype could have one btree > opclass that sorts on absolute value (distance from 0,0) and another > opclass that sorts on real part. In the first case "equal" values would > be members of the same circle around the origin, in the second case they > are members of the same vertical line.
The example that came to mind for me was a case-insensitive btree class for text. -- greg http://mit.edu/~gsstark/resume.pdf -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
