It surprised me that you can INCLUDE extra columns on non-UNIQUE
indexes, since you could just add them as regular indexed columns for
the same effect. It looks like when you do that in SQL Server, the
extra columns are only stored on btree leaf pages and so can't be used
for searching or ordering. I don't know how useful that is or if we
would ever want it... but I just wanted to note that difference, and
Agree
that the proposed UNIQUE ON FIRST n COLUMNS syntax and catalog change
can't express that.
Proposal suggests to work only with unique index by exactly your
reasons above.
--
Teodor Sigaev E-mail: teo...@sigaev.ru
WWW: http://www.sigaev.ru/
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