Salesforce apex triggers with practice examples

The database operations in Salesforce can handle either individual records or thousands of records simultaneously. Salesforce automatically divides incoming records into chunks of up to 200 records. Failing to bulkify the trigger code can quickly lead to reaching governor limits. Therefore, optimizing the trigger code for bulk record operations is crucial.

In order to bulkify resource intensive operations, use apex collections such as list, set and maps.

Here is a sample trigger

1. Query parent case records in trigger - Not bulkified

public class caseTriggerHandler{

    public static void beforeInsert(){
        List<Case> newCases = Trigger.new;
        for(Case caseRec : newCases){
            //Find the parent case ids from current case record
            Case parentCase = [Select id, caseNumber from Case where id =:caseRec.parentId limit 1];
        }
    }
}

2. Query parent case records in trigger - Bulkified

public class caseTriggerHandler{
            
    public static void beforeInsert(){
        List<Case> newCases = Trigger.new;
        List<Id> parentIds = new List<Id>();
        Map<Id,Case> mapIdParentCase = new Map<Id,Case>();
        
        //Find all parent case id's
        for(Case caseRec : newCases){
            parentIds.add(caseRec.parentId);
        }
        
        //Query all parent cases in one single query and use map to store them
        for(Case caseRec : [Select id,caseNumber from Case where id IN :parentIds]){
            mapIdParentCase.put(caseRec.id, caseRec);
        }

        for(Case caseRec : newCases){
            //Find the parent case ids from current case record -  no query inside for loop
            Case parentCase;
            if(mapIdParentCase.containsKey(caseRec.Id)){
                parentCase = mapIdParentCase.get(caseRec.Id)
            }
        }
    }
}

If you're looking to become an expert in Salesforce custom development, practicing writing efficient triggers is very critical. We've set up a number of scenarios where you can practice writing your own Apex code. Additionally, we have set up test cases to ensure that the code is working as expected and following Salesforce best practices. Following are a few sample scenarios.

1. Before Insert Trigger

Apex trigger to automatically populate the company field on leads

Company name on lead is a required field and inserting leads without company will cause the DML operation to fail. Solve the before insert apex trigger event to add a company name if the given lead doesn't have a company name populated.

Solve this practice example

2. After Insert Trigger

Apex trigger to log tasks automatically when a case is created

A company requires to automatically log a task when an inbound case is created with origin as phone.

Solve this practice example

Sometimes, business scenarios result in updating records in the same object within trigger contexts, which ends up running the same trigger that initiated the transaction. This will likely cause recursion if not handled correctly.

To avoid recursion in Apex triggers, identify the business logic that is likely to run again and isolate it with a static variable. Static variables retain their values between trigger contexts. Default the value of the static variable to false and execute your specific code only if the value is false. Once the code is executed, set it to true so that it will not rerun the next time.

In Salesforce, the order of execution outlines how different tasks unfold when saving or updating a record. It's important for developers to know this sequence to organize the execution of business logic when customizing an apex triggers.

The following is the execution flow of Apex triggers