On Wed, Apr 8, 2009 at 4:11 PM, John Lister
<john.lister...@kickstone.com> wrote:
Cheers for the pointers. Am i right in thinking that if i get an array of
arrays, the nested arrays are sent in wire format as well - it seems to
be
from the docs.
No, you can't easily get an array of arrays in Postgres. You can get
multi-dimensional arrays but that's one big array with multiple
dimensions. The text output form does look like an array of arrays
but they don't behave like you might think they would:
Cheers, it wasn't clear if you have an array of arrays of which the nested
ones were of a different type. but it looks like all the values have to be
the same type,
eg
select (array[array[1,2,3,4],array['test']])
fails..
this makes life simpler :)
Secondly, comments are a bit scarse in the code, but am i also right in
thinking that an array indexing can start at an arbitrary value? This
seems
to be what the lbound value is for... or is this a addition to deal with
nulls eg, {null, null, null, 4} would have a lbound of 3.... (or both)
No, nulls are handled using a bitmap inside the array data structure.
Array bounds don't have to start at 1, they can start below 1 or above 1.
postgres=# select ('[-2:-1][5:8]={{1,2,3,4},{5,6,7,8}}'::int[])[-2][5];
int4
------
Somehow missed the bounds in the docs. Cheers that has cleared that up...
JOHN
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