Cross-Cutting Platform Patterns

Salesforce Order of Execution (Record Save)

The full sequence when a record is saved. Every Apex and Flow developer needs this memorized.

Key implications:

• •Before-save Flows (step 4) run before before triggers (step 5)
• •Validation rules run twice — once before triggers, once after
• •Workflow field updates (step 11) can re-fire triggers, causing unexpected re-entry
• •After-save Flows (step 12) run after triggers but before commit — they share the transaction
• •Nothing is committed until step 16. Any unhandled exception rolls back everything

Governor Limits Philosophy

Salesforce is multi-tenant. Governor limits exist to prevent any single transaction from monopolizing shared resources.

Key principles:

• •Limits are per transaction, not per trigger or class
• •A trigger that calls a helper that calls a service — all share the same limits
• •Async contexts (Batch, Queueable, @future) get fresh limits per execution
• •Limits class methods let you check consumption at runtime

The multi-tenant mental model: Your org shares compute, storage, and I/O with thousands of other orgs on the same pod. Limits are the contract that keeps everyone honest.

Sharing Model Overview

Salesforce record access is deny by default — users see nothing unless access is explicitly granted.

Access Grant Hierarchy (evaluated in order)

OWD Settings

Apex Sharing Keywords

Rule of thumb: Use with sharing by default. Use without sharing only when the business logic requires seeing all records (e.g., a rollup service). Use inherited sharing for utility classes that shouldn't make their own sharing decision.

Security Model

Profile vs Permission Set

CRUD and FLS

Enforcement in Apex:

// Option 1: SOQL-level enforcement (Spring '20+)
List<Account> accts = [SELECT Name FROM Account WITH SECURITY_ENFORCED];

// Option 2: Strip inaccessible fields from results
SObjectAccessDecision decision = Security.stripInaccessible(
    AccessType.READABLE,
    [SELECT Name, AnnualRevenue FROM Account]
);
List<Account> safe = decision.getRecords();

// Option 3: Manual check (oldest approach)
if (Schema.sObjectType.Account.fields.Name.isAccessible()) {
    // safe to read
}

Platform Events

Publish/subscribe messaging on the Salesforce platform.

When to Use Platform Events

Key Characteristics

• •Fire-and-forget — publisher doesn't wait for subscribers
• •Survive transaction rollback — published events persist even if the publishing transaction fails (when using EventBus.publish after setSavepoint/rollback)
• •Replay — subscribers can replay events from the last 72 hours (or 3 days)
• •Governor limits — publishing counts against DML limits; subscribing via trigger counts against trigger limits
• •AFTER_COMMIT vs AFTER_EACH — controls when the trigger fires relative to the batch

// Publishing
MyEvent__e evt = new MyEvent__e(Payload__c = 'data');
Database.SaveResult sr = EventBus.publish(evt);

// Subscribing (Apex trigger)
trigger MyEventTrigger on MyEvent__e (after insert) {
    for (MyEvent__e evt : Trigger.new) {
        // process event
    }
}

Custom Metadata Types vs Custom Settings

Modern guidance: Prefer Custom Metadata Types for anything that should travel with your metadata deployments. Use Custom Settings only when you need mutability in Apex or per-user/profile configuration.