Using the h2 table function the sql would be somewhat like this:
select * from ST_Intersects(spatialTable, 'the_geom' ,
> ST_PolyFromText('POLYGON ((67 13, 67 18, 59 18, 59 13, 67 13))',1));
Here the function is in the FROM , not in the WHERE. Using index must be
transparent to users.
Le mardi 21 mai 2013 14:06:08 UTC+2, Noel Grandin a écrit :
>
> I don't understand the problem?
>
> What I'm saying is that you can define a function called ST_Intersects
> using CREATE ALIAS,
> and inside that function you can implement the necessary logic.
>
> From the perspective of a user of your extension, it should look like a
> normal part of the database.
>
> Or you are asking about something different?
>
> On 2013-05-21 13:27, Nicolas Fortin (OrbisGIS) wrote:
>
> I know function table but this lead to modifying the sql request and it is
> not in standard.
>
> Le mardi 21 mai 2013 11:52:15 UTC+2, Noel Grandin a écrit :
>>
>> See the section title "Using a function as a table" here
>> http://h2database.com/html/features.html#user_defined_functions
>>
>> On 2013-05-21 10:07, Nicolas Fortin (OrbisGIS) wrote:
>>
>> Discussion about user defined index on OTHER type.
>>
>> In spatial SQL the following request on an indexed geometry column would
>> use spatial index:
>>
>> select * from spatialTable where ST_Intersects(the_geom,
>>> ST_PolyFromText('POLYGON ((67 13, 67 18, 59 18, 59 13, 67 13))',1));
>>>
>>
>> Usage of ST_Intersects filter the_geom field by using BoundingBox stored
>> index of the spatialTable, then the method is applied on filtered rows.
>>
>> Can I do this by creating my own TableEngine ? There is an easier way
>> without modifying the sql request ? Maybe a way to let special kind of
>> function to alter the execution plan ?
>>
>> Thanks for your support.
>>
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