Salesforce Developer – Custom Settings & Metadata Questions

Custom Settings & Metadata - Q&A

1. Q1. What are Custom Settings and how do they differ from Custom Objects?
   Ans: Custom Settings are: - Cached in memory for fast access - Available in both Setup and non-Setup contexts - Two types: List and Hierarchy Key differences from Custom Objects: * No storage limits (excluded from data storage) * Faster retrieval (cached) * Specialized for configuration data * No triggers or validation rules
2. Q2. Explain the two types of Custom Settings and their use cases.
   Ans: Types: - List Custom Settings: * Store named collections of data * Global settings (e.g., API endpoints) * No user/organization hierarchy - Hierarchy Custom Settings: * User/profile-based overrides * Organization defaults with user exceptions * Profile-level settings with user overrides
3. Q3. How do you access Custom Settings in Apex?
   Ans: Access patterns:

   // List Custom Setting
   MyListSetting__c setting = MyListSetting__c.getInstance('SettingName');
   String value = setting.Field__c;
   
   // Hierarchy Custom Setting
   MyHierarchySetting__c userSetting = MyHierarchySetting__c.getOrgDefaults();
   String orgValue = userSetting.Field__c;
   
   // With user context
   MyHierarchySetting__c userSetting = MyHierarchySetting__c.getInstance(userId);
   String userValue = userSetting.Field__c;

4. Q4. What are the limitations of Custom Settings?
   Ans: Key constraints: - 1,000 List records per org - 300 Hierarchy records per org - 300 fields per setting - No triggers or validation rules - Cannot be used in SOQL WHERE clauses - Limited to 32KB per record
5. Q5. How do Custom Metadata Types differ from Custom Settings?
   Ans: Key differences: - Custom Metadata: * Deployable via Change Sets * Supports relationships * Can be used in formulas * Protected in managed packages * Supports custom fields - Custom Settings: * Faster runtime access * Hierarchy support * No deployment support * Limited field types
6. Q6. What is the Metadata API and when would you use it?
   Ans: The Metadata API: - Programmatic access to Salesforce metadata - CRUD operations on components (objects, fields, etc.) - Deployment automation - Package creation Common use cases: * CI/CD pipelines * Dynamic configuration * Org-to-org migrations
7. Q7. How do you implement Custom Settings for multi-currency scenarios?
   Ans: Implementation pattern:

   public class CurrencySettings {
     public static Decimal getExchangeRate(String currencyCode) {
       CurrencySetting__c setting = CurrencySetting__c.getInstance(currencyCode);
       return setting != null ? setting.Rate__c : 1.0;
     }
   }

   Considerations: - Cache frequently accessed values - Handle missing settings gracefully - Implement update mechanisms
8. Q8. What are the security considerations for Custom Settings?
   Ans: Security aspects: - No FLS enforcement (use with caution) - Visible to all users with object access - No sharing rules - Audit sensitive configuration data - Protect in managed packages - Consider encryption for PII
9. Q9. How do you test Custom Settings in unit tests?
   Ans: Testing approach:

   @isTest
   private class CustomSettingsTest {
     @isTest static void testHierarchySetting() {
       // Create test setting
       MySetting__c orgDefault = new MySetting__c(
         SetupOwnerId = UserInfo.getOrganizationId(),
         Field__c = 'TestValue'
       );
       insert orgDefault;
       
       // Test access
       MySetting__c retrieved = MySetting__c.getOrgDefaults();
       System.assertEquals('TestValue', retrieved.Field__c);
     }
   }

10. Q10. How do you handle Custom Settings in managed packages?
    Ans: Packaging considerations: - Use Protected settings for internal use - Public settings for subscriber customization - Document all settings clearly - Provide upgrade paths - Consider namespace prefixes - Test with and without namespace
11. Q11. What are the performance implications of Custom Settings?
    Ans: Performance factors: - Cached in memory (fast access) - No SOQL queries required - Minimal impact on governor limits - Consider bulk operations - Monitor record count limits - Use selective getInstance() calls
12. Q12. How do you migrate Custom Settings between orgs?
    Ans: Migration approaches: - Data Loader for List settings - Ant Migration Tool for metadata - Custom Apex scripts - Salesforce DX for version control - Manual creation for Hierarchy settings - Consider dependencies and references
13. Q13. What are the best practices for Custom Settings architecture?
    Ans: Recommended patterns: - Separate configuration from business logic - Use constants for field names - Implement caching layers - Validate setting values - Document all settings - Handle missing settings gracefully - Monitor usage and cleanup
14. Q14. How do you implement feature flags using Custom Settings?
    Ans: Feature flag pattern:

    public class FeatureManager {
      public static Boolean isFeatureEnabled(String featureName) {
        FeatureFlag__c flag = FeatureFlag__c.getInstance(featureName);
        return flag != null ? flag.Enabled__c : false;
      }
    }

    Benefits: - Gradual rollout control - Environment-specific features - Quick rollback capability - A/B testing support
15. Q15. Explain real-world Custom Settings scenarios.
    Ans: Practical applications: - API endpoint configuration - Email template settings - Integration credentials (encrypted) - Business process parameters - User preference storage - Org-wide defaults with overrides