Union of tables to give a spatial view

Question

I have a series of tables that i am trying to join together and display in a view. Some of them have a slightly different structure. They all have either a east/north, easting or northing, or a centrex and centrey. I then want the centroids for each polygon. If i run the select statements seperatly they select what i want, however when i put a union in it gives the following error message :
ERROR at line 1:
ORA-22901: cannot compare nested table or VARRAY or LOB attributes of an object
type
The SQL is as follows :
CREATE or REPLACE VIEW ALLSITES_V AS
select
'SSSI' desg,SSSI_NAME site_name,SSSI_ID site_code,EAST CENTREX,NORTH CENTREY,TO_NUMBER(sssi_id) isis_id,MI_STYLE,MI_PRINX,GEOLOC,sdo_geom.sdo_centroid(geoloc,0.001)
from SSSI
union
select
'SPA' desig,SPA_NAME site_name,SPA_CODE site_code,EASTING CENTREX,NORTHING CENTREY,ISIS_ID isis_id,MI_STYLE,MI_PRINX,GEOLOC,sdo_geom.sdo_centroid(geoloc,0.001)
from SPA
union
select
'RAMSAR' desg,RAMSAR_NAME site_name,RAMSAR_CODE site_code,EASTING CENTREX,NORTHING CENTREY,ISIS_ID isis_id,MI_STYLE,MI_PRINX,GEOLOC,sdo_geom.sdo_centroid(geoloc,0.001)
from RAMSAR
union
select
'SAC' desg,SAC_NAME site_name, SITE_CODE site_code,ISIS_ID isis_id,CENTREX,CENTREY,MI_STYLE,MI_PRINX,GEOLOC,sdo_geom.sdo_centroid(geoloc,0.001)
from SAC
I am assuming it is because i have not used the SDO_GEOM function in it's correct format. I would also like the view to show the centrex and y and also the MBR. It is will be used when passed through a WMS. I have missed out something fairly fundermental but i am not sure how to incorperate it.

Answer 1

Hi,
I created view:
CREATE OR REPLACE VIEW VIEW_ALL as
SELECT
ID, GEOMETRIE_ZNACKA as GEOMETRIE
FROM
TAB_A
WHERE
GEOMETRIE_ZNACKA is not null
UNION ALL
SELECT
ID, GEOMETRIE_SIPKA as GEOMETRIE
FROM
TAB_B
WHERE
GEOMETRIE_SIPKA is not null
I inserted geometry metadata:
insert into mdsys.user_sdo_geom_metadata (table_name,column_name,diminfo,SRID)
values ('VIEW_ALL','GEOMETRIE',MDSYS.SDO_DIM_ARRAY (MDSYS.SDO_DIM_ELEMENT('X',431700, 904600,0.01),
MDSYS.SDO_DIM_ELEMENT('Y',935200, 1227300,0.01)),2065);
Tables TAB_A and TAB_B have spatial index on column with geometry.
When I view the view VIEW_ALL in the spatial view (Georaptor) we get an error "ORA-01446".
Geometry data of tables TAB_A and TAB_B (directly) is viewed in spatial view (Georaptor) corectly.
Thanks
Petr Soucek