Question

Here is the query which will get me all the contacts have HD quality orders.

`Orderc__c[] orders = [SELECT id,customer__c, Customer__r.Number_of_HD_Orders__c,` `Quality_Code__c FROM Orderc__c where Quality_Code__c='HD'];`

then I change use these code to update the number of HD orders for each contact:

for(Orderc__c o: orders){
    if(o.Customer__r.Number_of_HD_Orders__c==null)
    o.Customer__r.Number_of_HD_Orders__c=0.0;
    o.Customer__r.Number_of_HD_Orders__c++;
}

now, the question is how can I update the contacts. as “update orders;” will not update the contacts.

Answer 1

You just need to add all the contacts to a new collection and then update that:

map<Id, Contact> contacts = new map<Id, Contact>();

for(Orderc__c o: orders) {
    if(o.Customer__r.Number_of_HD_Orders__c == null) {
        o.Customer__r.Number_of_HD_Orders__c=0.0;
    }

    Contact sContact = contacts.get(o.Customer__c);

    if(sContact != null) {
        sContact.Number_of_HD_Orders__c++;
    } else {
        o.Customer__r.Number_of_HD_Orders__c++;
        contacts.put(o.Customer__c, new Contact(id = o.Customer__c, Number_of_HD_Orders__c = o.Customer__r.Number_of_HD_Orders__c));
    }
}

update contacts.values();

Note this is very rough, doesn’t check for too many contacts in an update etc., but it should get your thinking in the right direction!