Add time type conversion info to docs

This commit is contained in:
Andrew Rabert 2019-03-24 18:19:32 -04:00
parent 953bc66ca6
commit 2bb3831807

View File

@ -633,6 +633,28 @@ to map `date.max` to :sql:`infinity`, for instance::
Of course it will not be possible to write the value of `date.max` in the
database anymore: :sql:`infinity` will be stored instead.
.. _time-handling:
Time handling
'''''''''''''
The PostgreSQL :sql:`time` and Python `~datetime.time` types are not
fully bidirectional.
Within PostgreSQL, the :sql:`time` type's maximum value of `24:00:00` is
treated as 24-hours later than the minimum value of `00:00:00`.
>>> cur.execute("SELECT '24:00:00'::time - '00:00:00'::time")
>>> cur.fetchone()[0]
datetime.timedelta(days=1)
However, Python's `~datetime.time` only supports times until `23:59:59`.
Retrieving a value of `24:00:00` results in a `~datetime.time` of `00:00:00`.
>>> cur.execute("SELECT '24:00:00'::time, '00:00:00'::time")
>>> cur.fetchone()
(datetime.time(0, 0), datetime.time(0, 0))
.. _adapt-list: