[postgis-users] Updated shapefile to update postgres database

Paragon Corporation lr at pcorp.us
Sat Jun 7 13:17:46 PDT 2008

Here is a thought, but not sure how slow this will be

DELETE FROM mystreets_table
WHERE street = 'N/A' AND 
EXISTS (SELECT n.street FROM mystreets_table n  WHERE (n.street <> 'N/A' AND
n.street > '')  AND ST_Equals(n.the_geom, mystreets_table.the_geom))

The st_equals might be better to replace with ~=  if you want to match exact
vertices.  I presume ~= is actually more efficient

Hope that helps,

-----Original Message-----
From: postgis-users-bounces at postgis.refractions.net
[mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of SenTnel
Sent: Saturday, June 07, 2008 2:25 AM
To: postgis-users at postgis.refractions.net
Subject: Re: [postgis-users] Updated shapefile to update postgres database

Hello! Im confused about this issue: 

I have a street (polyline) duplicated, one on top of the other, exact same
features, same "the_geom", but one bears the street name (column:"street")
"main street" and the other bears "N/A" as street name. Now my maps shows
the street but the name that shows is "N/A", and I would like to delete the
"N/A" polyline, how can i do basically this:

delete from mystreets_table street = 'N/A' where 'N/A' = street 'main
street'.the_geom (delete from mystreets table the street named 'N/A' where
the_geom in 'N/A'
equals the_geom in street "main street") another words, delete only the N/A
streets that the_geom is same as "main street", I hope you understand,


SenTnel wrote:
> Thanks Regina, Chris and all of you for your help. Im truly newby but 
> with such help Im ready to start the procedures, Ill keep you posted 
> of my progress or else if some issue comes along that may require some 
> light from you, Thanks again and I hope my problem/solution may be of 
> help to many others,
> Thanks again! 
> SenTnel wrote:
>> Hello!
>> I would like some help updating a postgres database. This is the problem:
>> We created the database using shp2pgsql to convert a shapefile that 
>> contains a city's street details (centerline), after we created the 
>> database we also created an aditional column to classify the street 
>> types
>> (eg: street, avenues, highways, etc.), now we are working on the 
>> original shapefile, updating new roads, changes made to highways due 
>> to constructions modifications, etc., and we want to upload the "updated"
>> shapefile, without afecting the actual database, another words, we 
>> would like to convert to postgres the updated shapefile with the new 
>> information (it cuold be the whole shapefile) but to keep the added 
>> clasiffication column intact. How can we do that?
>> Thanks

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