That’s actually a nice and generic serialization.
I think that we should do this similarly in ADM and AQL.
I.e. instead of using
interval-from-date("2012-01-01”, ”2013-04-01”)
(note the two parameters) in AQL and
interval-date("2012-01-01, 2013-04-01")
(not the single parameter) in ADM we should use
interval(date("2012-01-01”), date(”2013-04-01”))
for both. That would have a number of advantages:
1) It is consistent between AQL and ADM.
2) It is consistent with the JSON serialization.
3) It reduces the number of magic parsers.
4) It keeps the interval orthogonal to the type used in the interval.
On 4): While we don’t support intervals of other types than date,
time, and datetime so far, I think that we should change that and so
this would be a good step in that direction as well.
The disadvantages are
1) Incompatible AQL change
2) Incompatible ADM change
Thoughts?
Cheers,
Till
On 26 Jan 2016, at 11:46, Eldon Carman wrote:
I found that the lossless-JSON and clean-JSON printers were not being
used.
After connecting them to the respective JSON printer, I ran the query
again.
lossless-JSON result:
{ "orderedlist": [ { "date-interval": { "interval": { "start": {
"date":
"2012-01-01" }, "end": { "date": "2013-04-01" }}} }, {
"time-interval": {
"interval": { "start": { "time": "12:23:34.456Z" }, "end": { "time":
"15:34:45.567Z" }}} }, { "datetime-interval": { "interval": { "start":
{
"datetime": "2012-01-01T04:23:34.456Z" }, "end": { "datetime":
"2013-04-01T15:34:45.567Z" }}} } ] }
clean-JSON result:
[ { "date-interval": { "interval": { "start": "2012-01-01", "end":
"2013-04-01"}} }, { "time-interval": { "interval": { "start":
"12:23:34.456Z", "end": "15:34:45.567Z"}} }, { "datetime-interval": {
"interval": { "start": "2012-01-01T04:23:34.456Z", "end":
"2013-04-01T15:34:45.567Z"}} } ]
Is this what you would have expected?
On Mon, Jan 25, 2016 at 7:07 PM, Eldon Carman <[email protected]>
wrote:
Thanks Chris for adding a fourth option. This option would focus our
updates to only the ADM output.
Yes, both lossless-JSON and clean-JSON outputs would need to be check
also.
On Mon, Jan 25, 2016 at 5:58 PM, Chris Hillery
<[email protected]>
wrote:
I would vote for:
d. Update the serialized format to output "interval-from-date" and
put
both
dates in quotes.
I like the function name interval-from-date() better, and I don't
think
there's any need to maintain backwards compatibility with the old
name
which clearly never worked.
Couple thoughts, though: The serialized format really should be
"ADM",
not
"AQL". As such I don't think it should reference functions at all.
We
already do this for many datatypes, such as uuid("...") and
datetime("..."). Are those truly "Functions"? Are they
"constructors",
and
is that different? In any case, the answer for interval types should
be
consistent with that.
Final note: quite possibly the lossless-JSON and clean-JSON outputs
for
intervals are broken as well, and should be fixed.
Ceej
aka Chris Hillery
On Mon, Jan 25, 2016 at 5:36 PM, Till Westmann <[email protected]>
wrote:
Voting for a. Seems to be the least redundant option.
Cheers,
Till
On 25 Jan 2016, at 16:47, Eldon Carman wrote:
The interval field value printed in the ADM results can not be used
to
create an interval.
Intervals have several functions that are used to construct an
interval:
interval-from-date/time/datetime
and interval-start-from-date/time/datetime. It appears that this
is
the
only way to create an interval. Thus, a user must use one of these
function
to create an interval.
The following query shows how to create three intervals.
Query:
let $di := {"date-interval": interval-from-date("2012-01-01",
"2013-04-01")}
let $ti := {"time-interval": interval-from-time("12:23:34.456Z",
"233445567+0800")}
let $dti := {"datetime-interval":
interval-from-datetime("2012-01-01T12:23:34.456+08:00",
"20130401T153445567Z")}
return [$di, $ti, $dti];
Result:
{ "date-interval": interval-date("2012-01-01, 2013-04-01") }, {
"time-interval": interval-time("12:23:34.456Z, 15:34:45.567Z") },
{
"datetime-interval": interval-datetime("2012-01-01T04:23:34.456Z,
2013-04-01T15:34:45.567Z") } ]
Notice the results show interval-date("date, date") which is
different
than
the functions that are used to create a date interval. Notice that
interval-date does not exists in AsterixDB and that the input is a
single
string of dates separated by a comma. Below are some ideas on how
to
create
a round-trip for intervals.
Options for round tripping:
a: Rename "interval-from-date" to "interval-date" and update the
output to
put both dates in quotes.
b: Add alias for "interval-from-date" to "interval-date" and
update
the
output to put both dates in quotes.
c: Create an interval date constructor (called interval-date) that
can
parse the string "date, date".
The same process should be used for intervals with time and
datetime.
Thoughts?
