It’s true that you can’t define a GEOMETRY column in a foreign table. But you 
can define a VARCHAR column and apply the ST_GeomFromText to it, or if you want 
a point you can define a pair of DOUBLE columns and apply the ST_Point function.

In essence, our implementation of GEOMETRY is only an in-memory format right 
now, not an on-disk format. It’s a little less efficient than a native GEOMETRY 
data type but hopefully over time we will write optimizer rules that push down 
filters etc. so we don’t literally construct an in-memory geometry object for 
every row, only the rows we are interested in.

Julian

> On Nov 27, 2017, at 2:59 AM, Christian Tzolov <[email protected]> wrote:
> 
> Hey there,
> 
> I'm exploring the new Spatial (https://calcite.apache.org/docs/spatial.html)
> functionality and i've been trying to figure out what are the minimal
> requirements for using it with my custom adapter.
> 
> Following the guidelines i've set LENIENT  conformance in my jdbc URL (
> jdbc:calcite:conformance=LENIENT;
> ​model=...my model​
> ​
> ​
> ​)
> 
> But I am not sure how define the GEOMETRY column types?​
> 
> Currently my custom Schema/Table factory implementation infers the column
> types from the underlaying system's field types.
> 
> So it seems that i need to change my implementation and somehow to hint
> which fields needs to be mapped to GEOMETRY types?  Or perhaps i can try to
> do some expensive casting in SQL?
> 
> Are there any guidelines, examples ​for using Spatial functionality on 3rd
> party (e.g. custom) adapters?
> 
> Thanks,
> Christian

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