Salesforce II (Apex Focused)

Rules when working with databases

RULES:

• You cannot perform a callout after doing DML (database operations) in the same transaction. You must separate DML and callout using @future.

@future

• A decorator that runs a method later, asynchronously

• The new transaction has no uncommited DML and is allowed to make external API callouts

• When used:

  • To make callouts after DML

  • Separate DML and callouts

  • Offload long-running work

  • Keep UI/Triggers fast

• Key Rules:

  • Method must be static

  • Must return void

  • Arguments can only be primitive dtypes

• Exam Tips

  • Use on questions about DML / Callout

@InvocableMethod

• Method level. Makes a method callable from Flow, Process Builder, or external tools

• When Used:

  • For no-code Flow automation

  • Integrating Apex with automation tools

  • Calling Apex from a Flow to perform a task.

• Rules:

  • Must be static

  • Can only accept single-parameter types supported by Flow (list of primitives or sObjects)

• Exam Tips

  • Use for integration with Flow questions

Database.setSavepoint()

Creates a checkpoint in the current transaction

Database.rollback(savepoint)

rollsback database to the savepoint

@AuraEnabled

• Method or Property. Exposes Apex methods or properties to Lightning Components (Aura and LWC)

• Rules

  • Methods must be static to be called from LWC

  • Can specify cacheable=true to allow client-side caching

• Use cases:

  • Lightning Components calling Apex methods

  • Lightning Data Service Integrations

• Exam Tips

  • Frequently comes up in Lightning performance and caching questions

@TestMethod / @isTest

• Method/Class level. Marks methods or classes as unit tests

• Rules

  • Test methods cannot call future methods directly unless wraped in Test.startTest() / Test.stopTest()

  • Can be used on both classes and methods

• Use Cases

  • Writing Apex unit tests to satisfy coverage

  • Testing trigger and controller logic

• Exam Tips

  • PDII focuses heavily on testing best practices

@ReadOnly

• Method-level. Allows queries in read-only mode within Visualforce controllers or batch operations

• Rules

  • Cannot perform DML

  • Increases governor limits for queries

• Use Cases

  • Batch or high-volume query operations

  • Improving performance when only reading records

• Exam Tips

  • Use for optimization/performance questions

@Schedulable / @Scheduled

• Class-level. Allows the class to be scheduled to run at a specific time or interval

• Rules

  • Must implement Schedulable.execute() method

• Use Cases

  • Nightly updates, periodic reporting, data cleanup

@Batchable / @Database.Batchable

• Class-level. Marks a class as batch Apex, processing large datasets asynchronously

• Rules

  • Must implement start(), execute(), and finish()

  • Can be chained with other batch classes

• Use Cases

  • Large data updates or integrations

@Queueable

• Method/Class level. Enqueues Apex for asynchronous execution with more flexibility than @future

• Rules

  • Implements Queueable interface

  • Can chain jobs

  • Supports complex objects as parameters (unlike @future)

• Use Cases

  • Async callouts with complex objects

  • Background processing in trigger

@Deprecated

• Method/Class. Marks a method or class as deprecated, signaling that it should not be used in future development

• Use Cases

  • Legacy code maintenance

@InvocableVariable

• Property-level. Works with @InvocableMethod to expose input/output variables for Flow or Process Builder

• Use Cases

  • Define what a Flow is can pass to Apex

  • Define what Apex returns to Flow

@TestSetup

• Method level. Sets up common test data that can be reused across multiple test methods in a class.

• Use Cases

  • Reduces code deuplication in tests

  • Improves test performance

@Storable

@SeeAllData

• Method-level. allows test methods to access org data instead of creating mock records

• Use Cases

  • Quick testing without creating test records

@RestResource

• Class Level. Exposes an Apex class as a REST API endpoint

• Use Cases

  • Create RESTful web services for external systems

@HttpGet / @HttpPost / @HttpPut / @HttpDelete

• Method-level REST. Designates a method as handling a specific HTTP verb for a REST class

• Use Cases

  • Implement REST endpoints for CRUD operations