Hi all,

I have Responses__c and Response_Type__c objects . Response_Type__c is parent to Responses__c . Now I have Response_Type__c Id so written Query as follows to get Response_type__c fields as well as Responses__c fields 

List<Response_type__c> rtList = [select id,name,(select id,name from responses__c) from Response_type__c  where id =: rt.id];

Now it raising error 

Error: TestController Compile Error: Didn't understand relationship 'responses__c' in FROM part of query call. If you are attempting to use a custom relationship, be sure to append the '__r' after the custom relationship name. Please reference your WSDL or the describe call for the appropriate names.

then I changed the query as follows

List<Response_type__c> rtList = [select id,name,(select id,name from responses__r) from Response_type__c  where id =: rt.id];

still the same error 

Error: TestController Compile Error: Didn't understand relationship 'responses__r' in FROM part of query call. If you are attempting to use a custom relationship, be sure to append the '__r' after the custom relationship name. Please reference your WSDL or the describe call for the appropriate names.

so please help me in resolving this. please explain what is root cause