Interesting that DB2 does not allow VALID_END = NULL. Oracle does allow
this (although documentation for this is thin - the best I can find is this
example in the docs:
http://docs.oracle.com/cd/E16655_01/appdev.121/e17620/adfns_design.htm#CACJBAJJ
)
Agreed that closed-open semantics require (? >= VALID_START AND ? <
VALID_END) - my mistake. (But how does this support models which records
information at a point in time?)
On Tue, Dec 3, 2013 at 2:31 AM, Christian Mueller <
[email protected]> wrote:
> Hi Martin, DB2 does not allow VALID_END to be null. I am using 2999-12-31
> for example.
>
> DB2 also uses a closed/open period, the query should be
>
> (? >= VALID_START AND ? < VALID_END)
>
> I am wondering here, because using (less then or equal instead of less
> then)
>
> (? >= VALID_START AND ? <= VALID_END)
>
> would allow 2 historical versions for a point in time. The first version
> has this point in time as the end time, the second as the start time. Does
> this make sense ?, I think not.
>
>
> Cheers
> Christian
>
>
>
>
> On Mon, Dec 2, 2013 at 11:47 PM, Martin Davis <[email protected]> wrote:
>
>> Further to this issue, there's good news and bad news.
>>
>> The good news is that including the TIME= parameter eliminates the error,
>> and appears to work *as designed*. (Although it would be nice to be able
>> to omit the TIME= parameter and have some sensible default in place to
>> avoid the error. Perhaps the default could be TIME=<current time> ?)
>>
>> The bad news is that the temporal query emitted by GeoServer does not
>> match the temporal semantics of Oracle, and thus does not return enough
>> data. For a query of a time instant:
>>
>> GeoServer emits: SELECT ... WHERE ((? >= VALID_START AND ? <=
>> VALID_END) AND SDO_FILTER(... )
>>
>> As I mentioned before, Oracle uses a closed-open period model, with
>> VALID-END = NULL representing an open period. Therefore to return all
>> records current at the given time the query should be:
>>
>> SELECT ... WHERE ((? >= VALID_START AND (? <= VALID_END OR VALID_END IS
>> NULL) AND SDO_FILTER(... )
>>
>> In my particular case there are many records which have a NULL VALID_END,
>> and none of these get returned by the current GeoServer query.
>>
>> I suspect that other temporal databases (such as DB2) have similar
>> semantics.
>>
>> Any thoughts on how this might be addressed?
>>
>>
>>
>>
>>
>> On Mon, Dec 2, 2013 at 12:51 PM, Martin Davis <[email protected]> wrote:
>>
>>> We are attempting to use the WMS TIME parameter with a temporal view on
>>> Oracle 12c. The view is based on a join of several tables, one of which
>>> has geometry, and another of which has a valid time period defined using
>>> the columns VALID_START and VALID_END. According to Oracle 12c practice,
>>> rows which are do not have a set end time have VALID_END = NULL.
>>>
>>> When we set the Time dimension columns on the Layer, when a WMS request
>>> with no TIME parameter is made, we see an error:
>>>
>>> Caused by: java.io.IOException: Problem visiting CUT_BLOCK_FULL visiting
>>> CUT_BLOCK_FULL.fid--2a68243e_142b4b4a4e4_-4d8b:java.lang.NullPointerException
>>> at
>>> org.geotools.data.store.ContentFeatureSource.accepts(ContentFeatureSource.java:698)
>>> at
>>> org.geotools.data.store.ContentFeatureCollection.accepts(ContentFeatureCollection.java:121)
>>> at org.geoserver.wms.WMS.getCurrentTime(WMS.java:1044)
>>> at org.geoserver.wms.WMS.getTimeElevationToFilter(WMS.java:1208)
>>> at org.geoserver.wms.GetMap.executeInternal(GetMap.java:337)
>>> at org.geoserver.wms.GetMap.run(GetMap.java:201)
>>> at org.geoserver.wms.GetMap.run(GetMap.java:111)
>>> ... 104 more
>>> Caused by: java.lang.NullPointerException
>>> at java.sql.Timestamp.compareTo(Timestamp.java:513)
>>> at java.sql.Timestamp.compareTo(Timestamp.java:70)
>>> at org.geotools.feature.visitor.MaxVisitor.visit(MaxVisitor.java:104)
>>> at
>>> org.geotools.data.store.ContentFeatureSource.accepts(ContentFeatureSource.java:689)
>>>
>>> Is this expected behaviour? Is the TIME parameter required on all
>>> requests?
>>>
>>
>>
>>
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>
>
> --
> DI Christian Mueller MSc (GIS), MSc (IT-Security)
> OSS Open Source Solutions GmbH
>
>
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