[teiid-issues] [JBoss JIRA] (TEIID-3301) Add GEOMETRY_COLUMNS view

[Tom Arnold (JIRA)]

    [ https://issues.jboss.org/browse/TEIID-3301?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13037745#comment-13037745 ] 

Tom Arnold commented on TEIID-3301:
-----------------------------------

{quote}
I'm saying that as long as the source query has the direct projection of a geometry value, then we'll easily be able to associate the srid - but for a query with functions creating geometry values or inline views (although the logic to trace the value would be easy in the engine) would be more difficult to associate the srid.
{quote}
Ahhh, right; I can see now how that could get complicated. I think it would simplify things if we didn't allow such functions to be pushed down. I've only looked at conversion functions and filters so far, and this doesn't seem like it would be a major limitation in those cases at least.

Let's talk about plan b:
{quote}
For mysql we could use their internal format, for pg we could use ewkb, and oracle could use ewkt.
{quote}
I think we should emulate MySQL internal format for all. Another option would be to make something similar to EWKT by simply doing a concat of the SRID and WKT strings. In either case, we would read the SRID off the beginning of the result and then set it on the geometry type.

Couple of notes...
* We might want to be careful using MySQL internal format because I cannot find any documentation specifying it that it is what it appears to be.
* WKB-based format is preferable IMO because it's more compact.
* Postgres is the only database that supports the "extended" formats; Oracle does not support EWKT natively. JTS IO classes do not fully support the "extended" formats.

> Add GEOMETRY_COLUMNS view
> -------------------------
>
>                 Key: TEIID-3301
>                 URL: https://issues.jboss.org/browse/TEIID-3301
>             Project: Teiid
>          Issue Type: Feature Request
>            Reporter: Tom Arnold
>            Assignee: Steven Hawkins
>              Labels: spatial
>             Fix For: 8.10
>
>
> Another OGC Simple Features implementation detail. Basically this is like a specialized version of SYS.COLUMNS, and would be used to support GIS software (like GeoServer).
> http://www.carocoops.org/resources/doc/postgis/x321.html
> {code}
>   CREATE TABLE GEOMETRY_COLUMNS ( 
>     F_TABLE_CATALOG VARCHAR(256) NOT NULL, 
>     F_TABLE_SCHEMA VARCHAR(256) NOT NULL, 
>     F_TABLE_NAME VARCHAR(256) NOT NULL, 
>     F_GEOMETRY_COLUMN VARCHAR(256) NOT NULL,
>     COORD_DIMENSION INTEGER NOT NULL, 
>     SRID INTEGER NOT NULL, 
>     TYPE VARCHAR(30) NOT NULL 
>   )
> {code}
> I think we could implement this by storing SRID & friends as column properties, and then creating a view on SYS.COLUMNS & SYS.PROPERTIES.



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