[postgis-devel] [PostGIS] #944: typmod support for PostGIS geometry

PostGIS trac at osgeo.org
Sat May 7 08:37:47 PDT 2011

#944: typmod support for PostGIS geometry
 Reporter:  robe         |       Owner:  pramsey      
     Type:  enhancement  |      Status:  new          
 Priority:  medium       |   Milestone:  PostGIS 2.0.0
Component:  postgis      |     Version:  trunk        
 Keywords:               |  

 You said you are planning to put typmod for geometry, but didn't see a
 ticket in place for it.

 Have you thought about all the side issues.  I would be willing to help on

 Issues I think need to be addressed:

 What happens to geometry_columns.  Do we keep it as a table and create a
 view called ST_Geometry_Columns (which is what I believe SQL/MM says it
 should be called anyway).  This seems least invasive, though I see it
 posing problems for viewing and mapping tools.

 What happens with AddGeometryColumns, Populate etc.  Do they still
 register in geometry_columns and create constraints or do they do the
 typmod thing, register in geometry_columns (assuming its still a table) as

 I think you asked me once about why typmod wouldn't work in all cases.
 One thought I have is (which I need to test), it won't work for
 inheritance models where the geometry column type is different for each
 child table.

 The reason is I don't think geometry(POINT,...)  and geometry(POLYGON,...)
 will be considered the same type.  So the what we discussed in chapter 3
 of our book won't work with typmod. Would still be better with the old
 model of adding constraints. I still still need to verify that though. But
 really don't see how it would work since for example varchar(20) and
 varchar(50) are not legal in the same inheritance column.

 Anyway sorry to make this long and painful and raise all these issues.

Ticket URL: <http://trac.osgeo.org/postgis/ticket/944>
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