[QGIS-trac] [Quantum GIS] #2043: Merging multi-polygon-features on PostGIS fails

[Quantum GIS]

#2043: Merging multi-polygon-features on PostGIS fails
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   Reporter:  fritz123                                         |              Owner:  nobody
       Type:  bug                                              |             Status:  new   
   Priority:  major: does not work as expected                 |          Milestone:        
  Component:  Digitising                                       |            Version:  HEAD  
   Keywords:  postgis, merge, multipolgon, st_union, st_multi  |   Platform_version:        
   Platform:  Debian                                           |           Must_fix:  No    
Status_info:  0                                                |  
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 QGIS 1.3.0 can't merge features as described below:

 "The union operation would result in a geometry type that is not
 compatible with the current layer and therefore is canceled"

 Imagine a PostGIS-geometry-table, using the type multipolygon. Some of the
 features therein have islands, others don't. If you try to merge two
 features without islands, the resulting feature is type polygon. This also
 happens, when you try it manually using st_union. Since there is a
 constraint on the geometry column, the resulting feature can't be
 inserted. Using st_multi helps on database level.

 PostGIS-Version is 1.3.6.

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Ticket URL: <https://trac.osgeo.org/qgis/ticket/2043>
Quantum GIS <http://qgis.org>
Quantum GIS is an Open Source GIS viewer/editor supporting OGR, PostGIS, and GRASS formats