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

[Steven Hawkins (JIRA)]

    [ https://issues.jboss.org/browse/TEIID-3301?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13037943#comment-13037943 ] 

Steven Hawkins commented on TEIID-3301:
---------------------------------------

>  I think it would simplify things if we didn't allow such functions to be pushed down.

That would be any of the st_geomfrom* functions, udfs, st_setsrid, and any of the other construction/manipulation functions from the spec that get added.  Ideally that should all be allowed as pushdown.

> 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.

No, there doesn't seem to be an official statement on the internal storage. Just other sites confirming the srid bytes + wkb format.

> WKB-based format is preferable IMO because it's more compact. ... Oracle does not support EWKT natively.

I'm only suggesting reading oracle values as ewkt since it's easy to do clob concatenation in the source query.  We'd then yes have to convert to wkb for internal which would make getting the srid for oracle doubly expensive - unless the geometrytype also tracked its format.

>  JTS IO classes do not fully support the "extended" formats.

It does directly support the srid / three dimensional aspects of ewkb, which would be useful for reading values from postgis.

I will be adding a validation to the current logic though to prohibit reading ewkb values so that it's fully compatible with the expectations of the st_geomfromwkb function.


> 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.



--
This message was sent by Atlassian JIRA
(v6.3.11#6341)