Certification & Career Progression Roadmap

1// Certification prep: Key concepts tested in PD1 and PD2
2
3// PD1 — Bulkification (most frequently tested concept)
4public class OpportunityService {
5    // BAD — Not bulkified (fails PD1 exam question)
6    public static void updateAccountRevenue_BAD(List<Opportunity> opps) {
7        for (Opportunity opp : opps) {
8            Account acc = [SELECT AnnualRevenue FROM Account WHERE Id = :opp.AccountId];
9            acc.AnnualRevenue = (acc.AnnualRevenue == null ? 0 : acc.AnnualRevenue) + opp.Amount;
10            update acc; // DML inside loop!
11        }
12    }
13    
14    // GOOD — Bulkified (correct PD1 answer)
15    public static void updateAccountRevenue_GOOD(List<Opportunity> opps) {
16        // 1. Collect all Account IDs
17        Set<Id> accountIds = new Set<Id>();
18        for (Opportunity opp : opps) {
19            if (opp.AccountId != null) accountIds.add(opp.AccountId);
20        }
21        
22        // 2. Query once
23        Map<Id, Account> accountMap = new Map<Id, Account>(
24            [SELECT Id, AnnualRevenue FROM Account WHERE Id IN :accountIds]
25        );
26        
27        // 3. Calculate in memory
28        for (Opportunity opp : opps) {
29            Account acc = accountMap.get(opp.AccountId);
30            if (acc != null) {
31                acc.AnnualRevenue = (acc.AnnualRevenue == null ? 0 : acc.AnnualRevenue) 
32                    + opp.Amount;
33            }
34        }
35        
36        // 4. Single DML operation
37        update accountMap.values();
38    }
39}
40
41// PD2 — Advanced concepts: Queueable chaining, dynamic Apex
42
43// Queueable with chaining (PD2 level)
44public class DataCleanupQueueable implements Queueable {
45    private List<String> objectsToClean;
46    private Integer currentIndex;
47    
48    public DataCleanupQueueable(List<String> objects, Integer startIndex) {
49        this.objectsToClean = objects;
50        this.currentIndex = startIndex;
51    }
52    
53    public void execute(QueueableContext context) {
54        String objectName = objectsToClean[currentIndex];
55        
56        // Clean up old records for current object
57        String query = 'SELECT Id FROM ' + objectName + 
58            ' WHERE CreatedDate < LAST_N_DAYS:365 LIMIT 10000';
59        List<SObject> oldRecords = Database.query(query);
60        
61        if (!oldRecords.isEmpty()) {
62            Database.delete(oldRecords, false); // AllOrNone = false
63        }
64        
65        // Chain to next object if more remain
66        if (currentIndex + 1 < objectsToClean.size()) {
67            System.enqueueJob(
68                new DataCleanupQueueable(objectsToClean, currentIndex + 1)
69            );
70        }
71    }
72}
73
74// Dynamic Apex (PD2 topic)
75public class DynamicQueryBuilder {
76    public static List<SObject> search(
77        String objectName, 
78        Map<String, Object> filters,
79        Integer limitCount
80    ) {
81        String query = 'SELECT Id, Name FROM ' + 
82            String.escapeSingleQuotes(objectName) + ' WHERE ';
83        
84        List<String> conditions = new List<String>();
85        for (String field : filters.keySet()) {
86            Object value = filters.get(field);
87            if (value instanceof String) {
88                conditions.add(field + ' = \'' + 
89                    String.escapeSingleQuotes((String)value) + '\'');
90            } else {
91                conditions.add(field + ' = ' + value);
92            }
93        }
94        
95        query += String.join(conditions, ' AND ');
96        query += ' LIMIT ' + limitCount;
97        
98        return Database.query(query);
99    }
100}