[postgis-devel] [PostGIS] #1319: [raster] Make raster_columns a constraint-based view, replace AddRasterColumn with AddRasterConstraints and expand # of constraints on raster columns

[PostGIS]

#1319: [raster] Make raster_columns a constraint-based view, replace
AddRasterColumn with AddRasterConstraints and expand # of constraints on
raster columns
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 Reporter:  robe            |       Owner:  dustymugs    
     Type:  task            |      Status:  assigned     
 Priority:  critical        |   Milestone:  PostGIS 2.0.0
Component:  postgis raster  |     Version:  trunk        
 Keywords:                  |  
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Comment(by dustymugs):

 Patch attached for implementing raster_columns and raster_overviews as
 views.  Existing raster_columns and raster_overviews are renamed by
 prefixing "deprecated_" to the table name to give users time to run the
 functions AddRasterConstraints and AddOverviewContraints.

 The function sets for AddRasterColumn, DropRasterColumn and
 DropRasterTable still exist though in a limited capability as there are no
 raster_columns and raster_overviews tables.  This is so that the current
 python raster2pgsql.py loader can still be used until the C raster2pgsql.c
 is merged into trunk.

 Once the C raster2pgsql.c is merged into trunk, the functions for
 AddRasterColumn, DropRasterColumn and DropRasterTable will be deleted.
 The deprecated raster_columns and raster_overviews tables (prefixed with
 deprecated_) will not be touched as it is up to the user to drop those
 tables.

 With this change from tables to views, 3rd party plugins should be able to
 confidently use the information in the raster_columns and raster_overviews
 views as the data underlying the views are derived from existing table
 constraints.  If a value isn't present in the view, the corresponding
 constraint does not exist for that specific raster column.

 I plan on making an announcement on the postgis-devel list after I've made
 the commit so that people can understand the change, see how to establish
 constraints for their raster columns and apply the overview constraint to
 their overviews.  The announcement will be made on Monday 2011-12-05 as
 it's Friday evening (for me at least) and I don't expect many people to be
 active.

-- 
Ticket URL: <http://trac.osgeo.org/postgis/ticket/1319#comment:47>
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