[GUSDEV] PK constraints for version tables

[Deborah P. <pi...@pc...>]

I suggest that we drop the uniqueness constraint for PKs of version 
tables. PKs for these tables consist of the original PK and the 
modification date. Rapid computation can result in uniqueness 
copnstraint violations that are not remedied by date format changes. 
There doesn't seem to be a purpose in having these constraints for any 
of the version tables and dropping the constraints would not result in 
the loss of information or change query results. I don't know if there 
is implicit indexing on these keys but I wonder if this could be handled 
using explicit indexing.