On Sat, Aug 13, 2011 at 1:56 PM, Peter Eisentraut <peter_e@gmx.net> wrote:
> On fre, 2011-08-12 at 16:14 -0400, Robert Haas wrote:
>> On Fri, Aug 12, 2011 at 4:11 PM, Peter Eisentraut <peter_e@gmx.net> wrote:
>> > "A table is either a base table, a derived table, a transient table, or
>> > a viewed table." (SQL/MED adds "foreign table".)
>> >
>> > Just FYI.
>>
>> Base table seems clear enough, and a transient table sounds like a
>> temporary table, but what is a derived table? Is a viewed table a
>> view?
>
> A base table is either a permanent base table or (one of various kinds
> of) a temporary base table. A derived table is the result of a table
> expression, so this is more of a notional syntactic term. A transient
> table is, roughly speaking, OLD or NEW in a trigger. A viewed table is
> a view.
Ah.
Well, I guess I'm somewhat open to the idea of making all the places
where we mean, specifically, a table say "base table". Then we could
substitute the term "table" where we now say "relation".
On the other hand, I am also not entirely sure such a change in
terminology would be a net improvement in clarity, even though it does
seem better in some cases. For example, the CREATE TABLE command does
not create a viewed table; nor is there any CREATE VIEWED TABLE
command. On the flip side, for something like CLUSTER, "ERROR: %s is
not a base table" does seem like it could be more clear than just
"ERROR: %s is not a table".
So I'm not sure what to do.
--
Robert Haas
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