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

[PostGIS]

#1319: [raster] Make raster_columns a constraint-based view, replace
AddRasterColumn with ApplyRasterConstraints 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):

 Replying to [comment:37 mloskot]:
 > Replying to [comment:31 pracine]:
 > > Replying to [comment:30 mloskot]:
 > > > Indeed, ST_SameAlignment can not be used as replacement for the
 regular_blocking flag.
 > >
 > > Agreed. But you don't need regular_blocking anymore right?
 >
 > This constraint is supposed to serve certain use-cases where a table
 stores regular grid of tiles, so a client application can recognize this
 kind of configuration quickly and easily, and treat it in such specific
 case. The tiles storage/cache is one of important use cases for PostGIS
 Raster. Please, with all my respect, don't be scientific-ignorant here
 guys and don't make PostGIS Raster just another GRASS, please.
 >

 scientific-ignorant?  You'll have to elaborate on that.  Evidently, the
 research I'm involved with isn't scientific according to you.

 > If you decide to get rid of this flag, then the only way to determine if
 a table is tiles storage or not is to perform slow (!) query.
 >

 From the looks of it in the AddRasterColumn function, regular_blocking is
 just a boolean value passed with no true validation of making sure that no
 tiles overlap and there are no gaps.  As the appropriate constraints won't
 be added until after PostGIS 2.0 is released, we could just add a garbage
 constraint to indicate that a column is regularly blocked.

 > Per analogia, where vector folks here store SRID information?

 You're going to have to be more descriptive here.  Typically, SRID is
 found in the serialized data of geometry or raster.

-- 
Ticket URL: <https://trac.osgeo.org/postgis/ticket/1319#comment:39>
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