Need to Loop through Query/subquery result

Question

Account[] IPList = [SELECT Name,
                       (SELECT Product_Family__c 
                        FROM Product_Releases_del__r 
                        ORDER BY Product_Family__c ASC) 
                    FROM Account a 
                    WHERE ParentID =: AccountID];

I have the above query/subquery. It's a List of Lists that contains accounts and a list of account child objects. I need to essentially recreate the structure of the list of lists, so I can then exclude certain child objects based on their value. How would you go about iterating through both lists and adding the values to a list of Accounts/Child objects.

Answer 1

If the exclusions are simple you can do them at query time in the where:

IPList = [
        select Name, (
                select Product_Family__c
                from Product_Releases_del__r
                where ????
                ORDER BY Product_Family__c ASC
                )
        from Account
        where ParentID =: AccountID
        ];

Otherwise you will need to create your own class:

public AccountWrapper {
    public Account a {get; set;}
    public Product_Release_del__c[] prs {get; set;}
    public AccountWrapper(Account a) {
        this.a = a;
        this.prs = new Product_Release_del__c[] {}
    }
}

and do the filtering in Apex:

AccountWrapper[] ws = new AccountWrapper[] {};
for (Account a : [
        select Name, (
                select Product_Family__c
                from Product_Releases_del__r
                ORDER BY Product_Family__c ASC
                )
        from Account
        where ParentID =: AccountID
        ]) {
    AccountWrapper w = new AccountWrapper(a);
    for (Product_Release_del__c pr : a.Product_Releases_del__r) {
        if (pr ...) {
            w.prs.add(pr);
        }
    }
    ws.add(w);
}

because relationship collections can't be modified in Apex code once created via a query.

Answer 2

If you can't do the exclusions the way Keith C is suggesting, you can use a wrapper class to recreate the list, like this:

AccountWrapper[] wrapperList = new AccountWrapper[]{};
for (Account acct : IPList){
    AccountWrapper aw = new AccountWrapper();
    aw.acct = acct;
    if (!acct.Product_Release_del__c.isEmpty()){
        for (Product_Release_del__c : release : acct.Product_Release_del__c)
        aw.prodReleases.add(release);
    }
    wrapperList.add(aw);
}

public class AccountWrapper{
    Account acct {get;set;}
    Product_Releases_del__c[] prodReleases {get;set;}

    public AccountWrapper(){
        prodReleases = new Product_Releases_del__c[]{};
    }
}

Obviously you'll need to check the relationship names are correct, but this should do it.