On 26.07.2011 18:12, Dave Page wrote:
Hi Erwin
On Tue, Jul 26, 2011 at 4:47 PM, Erwin Brandstetter
<brandstet...@falter.at> wrote:
Aloha!
In v1.14 tables are opened with ORDER BY $pkey DESC.
I wonder if descending order ist intended. It used to be the other way round
and, as far as I am concerned, that was just fine in most cases.
We have the new feature "View Data" .. "View top / last 100 rows" anyway. No
need to change the default behavior?
The default is determined like this:
orderBy = table->GetQuotedPrimaryKey();
if (orderBy.IsEmpty()&& hasOids)
orderBy = wxT("oid");
if (!orderBy.IsEmpty())
{
if (pkAscending)
orderBy += wxT(" ASC");
else
orderBy += wxT(" DESC");
}
Essentially, we try to follow the ordering in the index.
Aloha Dave!
Fair enough. However, the following test-case shows the opposite effect in
pgAdmin:
> By default, B-tree indexes store their entries in ascending order with nulls
last.
http://www.postgresql.org/docs/9.0/interactive/indexes-ordering.html
CREATE TABLE test(test_id integer primary key, test text);
INSERT INTO test VALUES (1, 'top'), (2, 'middle'), (3, 'bottom')
-- Now open the table in the browser of pgAdmin 1.14 Beta 3 (sorts DESC;
incorrect)
-- Compare this with the behaviour in pgAdmin 1.12 (sorts ASC; correct)
Also, there are key types that do not sort. I quote the documementation:
> Of the index types currently supported by PostgreSQL, only B-tree can produce sorted output — the other index types return matching rows in an
unspecified, implementation-dependent order.
Is it safe to assume descending order if pkAscending is not true? Not sure what
"IsEmpty" implies exactly in the code ..
--
Erwin Brandstetter
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