id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
1471	gist geometric equality operator - for geometry uniqueness constraints	robe	pramsey	"The geometric equality operator we used to have in 1.3 (~=) would be even more useful now.  We can't call it ~= since that has already changed definition so much and is now just a bounding box equality (and not even that much because our bounding boxes are floats instead of the double precision of the geometry)

Something like  == might be a possible choice for bringing back the good old geometric equality ~= (NOTE this requies it have a RECHECK on it.  

The main benefit would be to be able to use exclusion constraints (introduced in PostgreSQL 9.0) to enforce geometry uniqueness.  Right now there is no guaranteed way of doing this and EXCLUSION CONSTRAINTS won't work with functions (so ST_OrderingEquals is out of the question) -- they have to be operators.

http://www.postgresql.org/docs/9.0/static/ddl-constraints.html
http://thoughts.j-davis.com/2010/09/25/exclusion-constraints-are-generalized-sql-unique/"	defect	new	medium	PostGIS Future	postgis	trunk