itemize more upgrade GOTCHAS

git-svn-id: http://svn.osgeo.org/postgis/trunk@7543 b70326c6-7e19-0410-871a-916f4a2858ee

diff --git a/MIGRATION b/MIGRATION
index a2efc71bbed838c3d884ea65822a66efe115888e..1dd4493b1c1333cf7ddd8f7f688f76d421be6a41 100644 (file)
--- a/MIGRATION
+++ b/MIGRATION
@@ -30,6 +30,31 @@ a table to a view.
   * Applications reading metadata from ``geometry_columns`` should expect
     that the geometry type strings will be mixed case and include the
     dimensionality modifiers. For example: PointZM, MultiLineStringZ.
+    
+  * If you have views built the old constraint way or that use processing functions to return new geometries, 
+       they will not register correctly in geometry_columns.  They will all appear as Geometry with srid=0.
+       In order to fix this, you have to cast the geometries in the view.
+       So for example, If you had a view that looked like this:
+       CREATE OR REPLACE VIEW vwparcels AS
+               SELECT gid, parcel_id, 
+                       ST_Transform(geom, 26986) As geom_26986, -- a transformed geometry
+                       geom, --one that used constraints before
+                       ST_Centroid(geom) As cent_geom -- one that used processing function
+               FROM parcels;
+               
+       You will need to drop and recreate the view. 
+       Sadly CREATE OR REPLACE will not work since the casting
+       makes geometries be treated as a different type as far as CREATE OR REPLACE is concerned
+       ---note for this might help to lookup in geometry_columns to see the raw table srid/type
+       Alternatively you can convert some of your table columns to typmod, then you would
+       only need to CAST when doing processing.  This however still requires you rebuild your dependent views
+       DROP VIEW vwparcels;
+       CREATE OR REPLACE VIEW vwparcels AS
+               SELECT gid, parcel_id, 
+                       ST_Transform(geom, 26986)::geometry(MultiPolygon,26986) As geom_26986,
+                       geom::geometry(MultiPolygon, 2249) As geom,
+                       ST_Centroid(geom)::geometry(Point,2249) As cent_geom
+               FROM parcels;
 
     
 Restoring data from prior versions -- GOTCHAS
@@ -50,4 +75,12 @@ file after the restore.  If you don't you will run into "function is not unique"
 The other issue with having the old functions is the old functions you restore will be bound to the old postgis library which is incompatible with the
 new postgis geometry structures.
 
-If you still require legacy functions, you can install the legacy.sql file after the uninstall_legacy.sql.
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+If you still require legacy functions, you can install the legacy.sql file after the uninstall_legacy.sql.
+
+GOTCHA with uninstall_legacy.sql
+--------------------------------
+The uninstall_legacy.sql will not be able to uninstall functions and will output errors detailing objects 
+using these functions that are currently being used in views and sql functions.
+If you run it in PgAdmin, the whole script will rollback not uninstalling anything. So you should run it in PSQL mode.
+If you get errors in uninstall_legacy.sql -- convert those views and sql functions to use the newer equivalent functions
+and then rerun the script again.
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