Spatial query inside the exists clause return ora-13226

Question

The following does not work:
select b.state, b.county from counties b where exists
(select 's' from states a where a.state = 'New Jersey'
and mdsys.sdo_relate (b.geom, a.geom, 'mask=INSIDE querytype=WINDOW' ) = 'TRUE');
ERROR at line 1:
ORA-13226: interface not supported without a spatial index
ORA-06512: at "MDSYS.MD", line 1723
ORA-06512: at "MDSYS.MDERR", line 8
ORA-06512: at "MDSYS.SDO_3GL", line 302
ORA-06512: at line 1
The following does work:
select b.* from states a,
counties b where a.state = 'New Jersey'
and mdsys.sdo_relate (b.geom, a.geom, 'mask=INSIDE querytype=WINDOW') = 'TRUE';
I found bug 1243095 telling that this is not a bug but a limitation of the spatial operator. It cannot be invoked on a table that is not spatially indexed. In fact, the table is indexed but oracle cannot find the spatial index because table b(counties) is declared outside the EXISTS clause.
In my case, I use object table. I cannot use the workaround specified above because I should use the DISTINCT clause but I cannot define the MAP and ORDER function (this is a general query).
I've found another workaround :
select b.state, b.county from counties b where exists
(select 's' from states a where a.state = 'New Jersey'
and mdsys.sdo_relate (a.geom, b.geom, 'mask=CONTAINS querytype=WINDOW') = 'TRUE');
but sdo_relate still doesn't use the spatial index of table b (even if I specify it explicitely in the operator) and the query is very slow (more than 15 minutes).
Is there a better workaround ?

Answer 1

OK but I work in object model.
And if I don't use the EXISTS clause, I must use the distinct clause.(I used the exists because of that)
If I will to retrieve all the country that have at least a state beginning with the C letter, I will wrote :
select c.* from country c, table(c.states) s where s.column_value.name like 'C%';
(It is a simplified request to express the problem)
In this case, I must use the distinct clause to select one occurence of each country objet (one country may contains more than one state beginning with C).
select distinct c.* from country c, table(c.states) s where s.column_value.name like 'C%';
For that, I must define a MAP or ORDER function for EACH type used in the country object.
My first question is : I must retrieve all different country objects. Why the request doesn't use the MAP or ORDER function of the country type to distinct them ? Is there another syntax (or a hint) to express that ?
In this case, it will make an ORA-00932 : incoherent datatype because the type of the nested table column cannot contain map or order method.
Any suggestion ?
Thanks in advance.