Pavel Stehule <pavel.steh...@gmail.com> writes:
>>> Probably there is less risk than 7 years ago, but still creating own
>>> syntax isn't the best idea. This is syntactic sugar only and different
>>> from ANSi SQL or common standard.
It's more than syntactic sugar; you are going to have to invent semantics,
as well, because it's less than clear what partial-field assignments
should do.
Assume a table with an int-array column, and consider
INSERT INTO foo SET arraycol[2] = 7, arraycol[4] = 11;
I wonder what the other elements of the array will be set to, and what
the array dimensions will end up being.
If there's a default expression for the array column, does that change
your answer?
If you say "we'll apply the default and then perform the SET assignments",
what's your criterion for deciding that you *don't* need to evaluate the
default? If the default has side effects (think nextval()) this is a
user-visible choice.
I don't say that these questions are unresolvable, but there is certainly
more here than meets the eye; and therefore there's a nonzero chance of
being blindsided if the SQL committee someday standardizes this syntax
and makes some different decisions about what it means.
regards, tom lane
--
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers
