Customer relationship between a Party and party_contact in oracle

How to get active user partyId in istore: 

RequestCtx.getPartyId()

Query to retrieve Organization contacts associated with account.

1) 

SELECT party_id
  INTO l_party_id
  FROM hz_cust_accounts
 WHERE account_number = p_customer_account_number;

--Pass this party_id as subject id to the below query to get organization contact;

SELECT *
  FROM hz_parties
 WHERE party_id IN (
          SELECT object_id
            FROM hz_relationships
           WHERE subject_id = l_party_id
             AND relationship_code LIKE 'CONTACT'
             AND status = 'A');

2)

select * from fnd_user where user_id in(

SELECT distinct f.user_id

                FROM oe_order_headers_all oh,              

                       hz_cust_accounts ca, 

     hz_cust_account_roles car,            

                       hz_parties p,            

                       hz_relationships prel  ,

     fnd_user f ,

     jtf_um_usertype_reg jutr             

                WHERE  ca.account_number=1000158 

    AND oh.sold_to_org_id=ca.cust_account_id        

                AND ca.party_id=p.party_id   

                AND p.party_type='ORGANIZATION'                

                AND car.cust_account_role_id=oh.sold_to_contact_id

                AND car.status='A'                              

                AND prel.party_id=car.party_id                  

                AND prel.status='A'

    AND f.customer_id=car.party_id                 

                AND jutr.user_id=f.user_id(+)                    

                AND jutr.status_code<>'REJECTED'

Customer relationship between a Party and party_contact in oracle:

=>  select header_id,sold_to_org_id,sold_to_contact_id into l_header_id,l_sold_to_org_id,l_sold_to_contact_id from oe_order_headers_all where order_number='p_order_number';

=>   select party_id into l_contact_party_id from HZ_CUST_ACCOUNT_ROLES where cust_account_role_id=l_sold_to_contact_id and cust_account_id=l_sold_to_org_id;