ADF BC selectOneChoice- populating an LOV based on another LOV

Question

scenario:
country:country_id, country_nme ViewObj: CityVO
city: city_id, country_id, country_nme ViewObj:CountryVO
cc: cc_id, country_id(FK), city_id(FK) ViewObj:CCVO
i have got two combo boxes(selectOneChoice) displaying
coutntry LOV which i created by selecting
base data source:CCVO, list datasource:countryVO
mapped attribute:country_id, display attrib:country_nme
similarly,city LOV which i created by selecting
base data source:CCVO, list datasource:cityVO
mapped attribute:city_id, display attrib:city_nme
objective:
now i need to populate the city LOV based on the country selected.
i added valueChangeListener on countryLOV so that it will get the country_id and execute view criteria on cityVO
problem:
problem is that i can not get country_id value! i explored methods on the selectOneChoice variable accessor and ValueChangeListerner component but no luck!
as i am displaying the country_nme so i have to use DCIteratorBinding to actually reach to the country_id value.
this seems to be a tedious way! plus if country selected again it gives nullPointerException on 3rd line:
DCBindingContainer dcBc = (DCBindingContainer)getBindings();       
DCIteratorBinding  iter = dcBc.findIteratorBinding("CountryVO1Iterator");    
Row row = iter.getRowAtRangeIndex(vce.getNewValue().toString()); //[error-prone] first time returns the database row of the selected country record.gives exception on 2nd time
Q1. is there any direct way of getting country_id, based on the display name?
Q2. is there any way to refresh the iterator? iter.release(), iter.clear() did not help
Regards,
Rabs

Answer 1

Hi
This is not possible in Discoverer 4i. The concept of Cacading lists of values was only introduced in Discoverer 10g R2 (10.1.2).
Now there's a good reason to upgrade :-)
Best wishes
Michael