[postgis-users] Re: How to populate a column with results of isvalid

[Intengu Technologies]

Thanks Regina your solution was spot on.

On 12/31/08, Obe, Regina <robe.dnd at cityofboston.gov> wrote:
> You wouldn't use that for tagging.  That is used if you want to prevent
> people from adding invalid geometries into your table.  If you have
> already got invalid geometries it will just fail since you have already
> violated the rule you are trying to establish.
>
> To add a field
>
> ALTER TABLE mytable ADD COLUMN the_geom_is_valid boolean ;
> UPDATE mytable SET the_geom_is_valid = ST_IsValid(the_geom);  //will
> update existing
>
> Unfortunately you can't put in a default value that references another
> column which I think you may be looking for if you want to continually
> add new data and have that field automatically fill.  For that you'll
> need a (preferably BEFORE TRIGGER).
>
> Hope that helps,
> Regina
>
>
>
> -----Original Message-----
> From: postgis-users-bounces at postgis.refractions.net
> [mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of
> Intengu Technologies
> Sent: Wednesday, December 31, 2008 10:25 AM
> To: PostGIS Users Discussion
> Subject: [postgis-users] How to populate a column with results of
> isvalid
>
> I have loaded a polygon shapefile into postgis and would like to tag
> each row with the results of st_isvalid in a new field. I found this
> query in the postgis manual "ALTER TABLE mytable ADD CONSTRAINT
> geometry_valid_check CHECK (isvalid((the_geom));" when I run the query
> it picks an invalid geometry and stops
>
> --
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> Sindile Bidla
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