Good! And good to know. Karl-Magnus
Från: Árni Geirsson [mailto:a...@alta.is] Skickat: den 12 april 2017 15:19 Till: Steve Toutant Kopia: Karl Magnus Jönsson; qgis-user@lists.osgeo.org Ämne: Re: [Qgis-user] Unique IDs in a PostGIS view I left the over clause empty. Based on your suggestion, I tried the following: SELECT row_number() over ( order by fillline_a.id<http://fillline_a.id>, (st_dumppoints(fillline_a.geom)).path, st_x((st_dumppoints(fillline_a.geom)).geom), st_y((st_dumppoints(fillline_a.geom)).geom) ) as id, (fillline_a.z)::real AS z, (st_dumppoints(fillline_a.geom)).path[1] as p, st_x((st_dumppoints(fillline_a.geom)).geom) as x, st_y((st_dumppoints(fillline_a.geom)).geom) as y, ((st_dumppoints(fillline_a.geom)).geom)::geometry(Point,3057) AS geom FROM v0103.fillline_a The problem here is that everything in the over clause remains constant for each line and therefore the row_number is not incremented for each point. Maybe I am doing something wrong. Anyway, I wonder if it should count as a bug in QGIS that I can use the nextval() method to see the correctly constructed view when listed as a table in DB Manager but not on the map canvas. Anyway, I found a simple way around the numbering problem: with t as ( select z, (st_dumppoints(fillline_a.geom)).geom from v0103.fillline_a) select row_number() over () as id, z, geom from t Problem solved :) Thanks for the input. Árni Árni Geirsson Alta ehf // +354 582 5000 // +354 897 9549 On 12 April 2017 at 12:48, Steve Toutant <steve.tout...@inspq.qc.ca<mailto:steve.tout...@inspq.qc.ca>> wrote: It would help to see how you used row_number and what field you put in it. You could create row_number after the dumping select row_number() OVER (ORDER BY path,st_x,st_y.......) AS id, * from (select .ST_DumpPoints..... from ...) -----"Qgis-user" <qgis-user-boun...@lists.osgeo.org<mailto:qgis-user-boun...@lists.osgeo.org>> a écrit : ----- A : Karl Magnus Jönsson <karl-magnus.jons...@kristianstad.se<mailto:karl-magnus.jons...@kristianstad.se>> De : Árni Geirsson Envoyé par : "Qgis-user" Date : 12/04/2017 07:13 Cc: "qgis-user@lists.osgeo.org<mailto:qgis-user@lists.osgeo.org>" <qgis-user@lists.osgeo.org<mailto:qgis-user@lists.osgeo.org>> Objet : Re: [Qgis-user] Unique IDs in a PostGIS view Thanks for the suggestion Karl. I have used row_number() also but in the case of dumping vertex points from a line, multiple points are created from each line feature and therefore, the row_number is repeated for all points on the same line. Árni Árni Geirsson Alta ehf // +354 582 5000<tel:582%205000> // +354 897 9549<tel:897%209549> On 12 April 2017 at 09:45, Karl Magnus Jönsson <karl-magnus.jons...@kristianstad.se<mailto:karl-magnus.jons...@kristianstad.se>> wrote: Hi! I’ve used something like this to get unique Ids: SELECT row_number() OVER (ORDER BY s.omrade_id, s.kod) AS id, …. ORDER BY s.omrade_id, s.kod; If the ordering isn’t necessary I guess you can skip that. https://www.postgresql.org/docs/current/static/functions-window.html Karl-Magnus Jönsson Från: Qgis-user [mailto:qgis-user-boun...@lists.osgeo.org<mailto:qgis-user-boun...@lists.osgeo.org>] För Árni Geirsson Skickat: den 12 april 2017 11:34 Till: qgis-user@lists.osgeo.org<mailto:qgis-user@lists.osgeo.org> Ämne: [Qgis-user] Unique IDs in a PostGIS view I am trying to create a view that extracts vertices from lines using ST_DumpPoints and to get unique IDs I have set up a sequence to generate the numbers using nextval(). The query executes normally in the DB Mananger and I see the results as a table in the table view. However, when I attempt to load the results of the view as a layer in QGIS, I get an error: "Database error: ERROR: cannot execute nextval() in a read-only transaction". No features are loaded. Are there any smart tricks out there to work around this or other means of generating the IDs? Árni Geirsson _______________________________________________ Qgis-user mailing list Qgis-user@lists.osgeo.org<mailto:Qgis-user@lists.osgeo.org> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user Si vous n'êtes pas le destinataire de ce message, veuillez le détruire près avoir informé l'expéditeur de son erreur. Par ailleurs, il est interdit de copier ou de modifier ce courriel sans l'autorisation de l'auteur. L'Institut national de santé publique du Québec n'assume aucune responsabilité à l'égard du contenu des messages personnels envoyés par ses employés.
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