On 10/01/2016 02:45 AM, Jim Nasby wrote:
On 9/29/16 1:51 PM, Heikki Linnakangas wrote:
Now, back to multi-dimensional arrays. I can see that the Sequence
representation is problematic, with arrays, because if you have a python
list of lists, like [[1, 2]], it's not immediately clear if that's a
one-dimensional array of tuples, or two-dimensional array of integers.
Then again, we do have the type definitions available. So is it really
ambiguous?
[[1,2]] is a list of lists...
In [4]: b=[[1,2]]
In [5]: type(b)
Out[5]: list
In [6]: type(b[0])
Out[6]: list
If you want a list of tuples...
In [7]: c=[(1,2)]
In [8]: type(c)
Out[8]: list
In [9]: type(c[0])
Out[9]: tuple
Hmm, so we would start to treat lists and tuples differently? A Python
list would be converted into an array, and a Python tuple would be
converted into a composite type. That does make a lot of sense. The only
problem is that it's not backwards-compatible. A PL/python function that
returns an SQL array of rows, and does that by returning Python list of
lists, it would start failing.
I think we should bite the bullet and do that anyway. As long as it's
clearly documented, and the error message you get contains a clear hint
on how to fix it, I don't think it would be too painful to adjust
existing application.
We could continue to accept a Python list for a plain composite type,
this would only affect arrays of composite types.
I don't use PL/python much myself, so I don't feel qualified to make the
call, though. Any 3rd opinions?
- Heikki
--
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers
