Easy Apex Trigger Practice Problems

Problem Statement

Write a before insert / before update trigger on Account.

Set the Rating field based on AnnualRevenue:

• Revenue > 1,000,000 → Rating = Hot
• Revenue 100,000 – 1,000,000 → Rating = Warm
• Revenue < 100,000 → Rating = Cold

Must handle bulk operations of up to 200 records without hitting governor limits.

Trigger Context Variables

• Trigger.isBefore — true when running in a before context
• Trigger.isInsert — true on insert events
• Trigger.isUpdate — true on update events
• Trigger.new — list of new/updated records (available on insert & update)

Constraints

• No SOQL inside the loop
• Must be fully bulkified
• Handle null AnnualRevenue gracefully

Problem Statement

Write a before insert / before update trigger on Opportunity that prevents saving a record when the CloseDate is set to a date in the past.

Use addError() to surface a user-friendly validation message directly on the field.

Requirements

• Trigger must fire on before insert and before update
• Compare CloseDate against Date.today()
• Call opp.CloseDate.addError() with a descriptive message
• Handle bulk operations — no SOQL inside the loop
• Allow CloseDate equal to today (same-day close is valid)

Example

CloseDate = yesterday → Error: "Close Date cannot be in the past."
CloseDate = today     → OK
CloseDate = tomorrow  → OK

Problem Statement

Write a before insert / before update trigger on Employee__c that validates the Salary__c field.

• Salary must not be null
• Salary must be greater than 0
• Salary must not exceed $500,000

Use addError() on the field so the error appears inline in the UI.

Example

Salary__c = null    → Error: "Salary is required."
Salary__c = -1000  → Error: "Salary must be greater than 0."
Salary__c = 600000 → Error: "Salary cannot exceed $500,000."
Salary__c = 90000  → OK

Problem Statement

Write a before insert / before update trigger on Account that normalizes the Website field.

If the Website is set but does not start with http:// or https://, prepend https:// automatically.

Examples

Website = null              → unchanged (skip)
Website = 'example.com'    → 'https://example.com'
Website = 'http://x.com'   → unchanged
Website = 'https://x.com'  → unchanged

Problem Statement

Write a before insert / before update trigger on Opportunity that validates the Amount field must be greater than zero.

Null and zero amounts are both invalid — attach the error to the Amount field using addError().

Constraints

• Bulk-safe — no SOQL inside the loop
• Error must be on the Amount field, not on the record

Problem Statement

Write a before insert / before update trigger on Case that automatically sets the Priority field based on keywords in the Subject.

• Subject contains urgent, critical, or asap → Priority = High
• Subject contains help or question → Priority = Low
• All other non-null subjects → Priority = Medium
• Null subject → skip (no change)

Matching is case-insensitive.

Problem Statement

Write a before insert trigger on Lead that sets a custom Lead_Score__c field based on LeadSource:

• Web → 80
• Phone Inquiry → 60
• Trade Show → 40
• Everything else → 20

Problem Statement

Write a before insert, before update trigger on Opportunity that validates:

• Amount must be greater than 0
• CloseDate must not be in the past

If either condition fails, call addError() on the record with a descriptive message.

Problem Statement

Write a before delete trigger on Opportunity that prevents deletion of any Opportunity with StageName = 'Closed Won'.

Add an error message: "Cannot delete a Closed Won opportunity."

Problem Statement

Write a before insert trigger on Case that sets a custom text field Created_By_Name__c to the full name of the user inserting the record.

Use UserInfo.getUserId() to get the current user, then query the User object to get Name.

Problem Statement

Write a before insert trigger on Lead that sets default values for missing fields:

• If LeadSource is null, set it to "Web"
• If Status is null, set it to "New"
• If Rating is null, set it to "Cold"

Key Concept — Before Insert Trigger

In a before insert trigger, Trigger.new contains the new records before they are saved. Records have no Id yet. You can modify fields directly — no DML needed. Trigger.old is null in before insert because there are no prior versions.

Constraints

• Only use before insert — do not trigger on update
• Do not overwrite values that are already set
• Must be bulkified — handle 200 records in one transaction

Problem Statement

Write an after insert trigger on Account. Whenever a new account is created with Industry = 'Technology', automatically create a Contact for that account using:

• Contact.LastName = Account.Name
• Contact.Phone = Account.Phone
• Contact.AccountId = the new account's Id

Best Practices

• Use after insert (Ids are available after insert).
• Build the full list of new Contacts first, then insert in a single DML call.
• Skip accounts without Industry = 'Technology' silently.

Problem Statement

Write a before insert / before update trigger called OpportunityProbabilityTrigger on Opportunity that automatically sets the Probability field based on StageName using the following mapping:

Requirements

• Fire on before insert and before update
• Use a Map<String, Integer> to store the stage-to-probability mapping
• Only set Probability when StageName is non-null and exists in the map
• Leave Probability unchanged for stages not in the map
• Bulk-safe — handle up to 200 records with no SOQL inside the loop

Problem Statement

Write a before insert / before update trigger on Opportunity that prevents reps from setting a CloseDate in the past.

If CloseDate < Date.today(), call addError() on the CloseDate field with the message 'Close Date cannot be in the past.'

Best Practices

• Use a before trigger — no DML needed.
• Delegate logic to a handler class OpportunityTriggerHandler.
• Bulkify: iterate Trigger.new, not a single record.
• Guard null: only validate when CloseDate != null.

Problem Statement

Write a before insert / before update trigger on Account that automatically sets a custom field Revenue_Tier__c based on AnnualRevenue:

• > 10,000,000 → Enterprise
• 1,000,000 – 10,000,000 → Mid-Market
• 100,000 – 1,000,000 → SMB
• < 100,000 or null → Startup

Best Practices

• No SOQL — purely in-memory classification.
• Handle null AnnualRevenue (classify as Startup).
• Bulkify: handle 200 records in one invocation.
• Delegate to handler class AccountTriggerHandler.

Problem Statement

Write a before insert / before update trigger on Contact that rejects any Email address that does not end with @salesforce.com.

Requirements

• Fires on before insert and before update.
• Skip Contacts where Email == null — null emails are allowed.
• Call c.Email.addError('Email must be a @salesforce.com address.') to highlight the specific field.
• Store the allowed domain in a constant (final String ALLOWED_DOMAIN).

Best Practices

• Use .toLowerCase().endsWith() for case-insensitive comparison.
• Call addError() on the field (c.Email.addError()), not on the record — this highlights the field in the UI.
• Use a named constant for the domain string — never a magic string in the condition.
• No SOQL or DML needed — pure in-memory validation.

Problem Statement

Write a before insert / before update trigger on Account with handler AccountRatingHandler that sets Rating based on AnnualRevenue.

Rating Rules

• Hot — AnnualRevenue ≥ 10,000,000
• Warm — AnnualRevenue 1,000,000 – 9,999,999
• Cold — AnnualRevenue < 1,000,000 or null

Best Practices

• On updates, skip records where AnnualRevenue has not changed.
• Handle null AnnualRevenue explicitly (assign Cold).
• Tests cover all four paths: Hot, Warm, Cold (low), Cold (null), and unchanged update.

Problem Statement

Write a before delete trigger on Opportunity that prevents any closed Opportunity (IsClosed = true) from being deleted.

Requirements

• Fires on before delete — use Trigger.old.
• Loop Trigger.old; if opp.IsClosed == true, call opp.addError('Closed Opportunities cannot be deleted...').
• No SOQL or DML needed — pure in-memory check on the record being deleted.

Best Practices

• Use the formula field IsClosed — it is automatically true for both Closed Won and Closed Lost, so you do not need to check each stage name.
• addError() on the record (not a field) prevents the delete and shows the message to the user.
• No SOQL needed — all required data is available on Trigger.old.

Problem Statement

Implement a Trigger + Handler that automatically sets LeadSource to 'Web' when a Lead is inserted without a source.

Trigger Requirements

• Fire on before insert only
• No logic in the trigger — delegate to the handler

Handler Requirements

• Store the default value in a named constant
• Only set LeadSource when it is blank/null — never overwrite an existing value
• Bulk-safe: iterate over the full list

Test Class Requirements

• Assert blank source defaults to 'Web'
• Assert existing source is preserved
• Bulk test with 200 leads

Problem Statement

Write an Apex trigger PreventAccountDeletion on the Account object that fires before delete.

If the Account being deleted has one or more related Opportunity records, call addError() on that Account to block the deletion with the message:
"Cannot delete an account with related opportunities."

Requirements

• Bulk-safe: handle multiple Account deletions in one transaction.
• Use a single SOQL query outside any loop.
• Add the error on the Account record, not a field.

Expected Behaviour

• Account with 0 Opportunities → deleted successfully.
• Account with ≥ 1 Opportunity → blocked with error message.

Problem Statement

Write an Apex trigger PreventAccountDeletionContacts on Account that fires before delete.

If any Account being deleted has one or more related Contact records, block deletion with addError() and the message:
"Cannot delete an account with related contacts."

Requirements

• Bulk-safe — use aggregate SOQL, not a per-record query.
• Use a Map<Id, Integer> to track counts per Account.

Problem Statement

Write an Apex trigger AccountForContact on Contact that fires after insert.

When a Contact is inserted with a non-null AccountId, set the checkbox field Contact_Created__c = true on the related Account.

Requirements

• Collect all Account IDs from the batch in one pass.
• Query only Accounts that need to be updated.
• Issue a single bulk DML update.

Problem Statement

Write an Apex trigger DefaultContactOnAccount on Account that fires after insert.

For every newly created Account, automatically create a default Contact with the following values:

• FirstName = 'Info'
• LastName = 'Default'
• Email = 'info@websitedomain.tld'
• AccountId = the new Account's Id

Requirements

• Create one Contact per Account in the batch.
• Use a single bulk insert — no insert inside a loop.

Problem Statement

Write an Apex trigger AutoAssignCaseOwner on Case that fires before insert.

If a Case is being created with Priority = 'High', automatically assign its OwnerId to the Id of the queue named 'High Priority Cases'.

Requirements

• Query the Group object where Type = 'Queue' and Name = 'High Priority Cases'.
• Guard against the queue not existing — only assign if the queue is found.
• This is a before trigger — set OwnerId directly on the Case record.

Problem Statement

Write an Apex trigger PrefixDrTrigger on the Lead object that fires before insert and before update.

For every Lead, if FirstName is not null and does not already start with 'Dr ', prepend 'Dr ' to FirstName.

Requirements

• Fires on both insert and update.
• Skip leads where FirstName is null or already starts with 'Dr '.
• Bulk-safe: handles multiple leads in one transaction.

Problem Statement

Write an Apex trigger UpdateAccountRating on the Opportunity that fires after insert and after update.

Whenever StageName is 'Closed Won', set the related Account's Rating to 'Hot'.

Requirements

• Bulk-safe: one SOQL outside loop, one DML update.
• Only update accounts linked to Closed Won opportunities.

Problem Statement

Write an Apex trigger UpdateAccountNameWithPhone on the Account that fires before update.

When the Phone field changes and is not null, set
Name = Name + ' - ' + Phone.

Requirements

• Only fire when Phone actually changed.
• Skip if the new Phone is null.
• Bulk-safe.

Problem Statement

Write an Apex trigger SyncAccountCityToOpportunities on the Account that fires after update.

When City__c changes, update all related Opportunity City__c to match.

Requirements

• Only sync when City__c actually changes.
• Bulk-safe: one SOQL, one DML.
• Use Trigger.newMap to get the new city value for each Opportunity.

Problem Statement

Write an Apex trigger CascadePhoneFromOpportunity on the Opportunity that fires after update.

When TestPhoneOpportunity__c changes, sync the new value to the related Account's TestPhoneAccount__c and all related Contacts' TestPhoneContact__c.

Requirements

• One SOQL with parent-to-child Contacts subquery.
• Bulk-safe: one SOQL, separate DML for accounts and contacts.

Problem Statement

Write an Apex trigger AddTaskOnClosedWon on the Opportunity that fires after insert and after update.

When StageName becomes 'Closed Won' (and was NOT already Closed Won on update), create a Task: Subject = 'Follow Up Test Task', WhatId = Opportunity Id, Status = 'Not Started', Priority = 'Normal'.

Requirements

• On update: only create task when StageName transitions TO 'Closed Won'.
• Bulk-safe: collect tasks, insert once.

Problem Statement

Write an Apex trigger DivideAccountBalance on the Account that fires after insert and after update.

For each Account with Balance__c > 0 and related Contacts, divide Balance__c equally by setting each Contact's IndividualBalance__c.

Requirements

• Use parent-to-child SOQL with Contacts subquery.
• Skip Accounts with no Contacts.
• Bulk-safe: one SOQL, one DML.

Problem Statement

Write an Apex trigger AddContactForHighRevenue on the Account that fires after insert.

For every new Account where AnnualRevenue > 50000, create a Contact with FirstName = 'Smriti', LastName = 'Sharan', AccountId = Account Id.

Requirements

• Only fires on insert.
• Only create contact when AnnualRevenue is not null and > 50000.
• Bulk-safe: collect contacts, insert once.

Problem Statement

Write an Apex trigger CreateContactForBanking on the Account that fires after insert.

For every new Account where Industry == 'Banking', create a Contact with LastName = Account Name, Phone = Account Phone, AccountId = Account Id.

Requirements

• Fires only on insert, only when Industry = 'Banking'.
• Bulk-safe: collect contacts, insert once.

Problem Statement

Write an Apex trigger SetCaseFieldsOnEmailOrigin on the Case that fires before insert.

For every new Case where Origin == 'Email', set Status = 'New' and Priority = 'Normal'.

Requirements

• Fires only on insert, only when Origin = 'Email'.
• No DML needed — it is a before trigger.
• Bulk-safe.

Problem Statement

Write an Apex trigger SetLeadRatingBySource on the Lead that fires before insert.

For every new Lead: if LeadSource == 'Web' → Rating = 'Hot'; otherwise → Rating = 'Cold'.

Requirements

• Fires only on insert. No DML needed. Bulk-safe.

Problem Statement

Write an Apex trigger SetContactOtherPhone on the Contact that fires before insert.

For every new Contact with an AccountId, look up the related Account's Phone and set the Contact's OtherPhone to that value.

Requirements

• Skip contacts without AccountId.
• One SOQL outside loop, Map for lookups.
• No DML — before trigger.

Problem Statement

Write an Apex trigger AssignOwnerByIndustry on the Account that fires before insert.

For every new Account where Industry == 'Education', assign ownership to the User with username 'smriti@sfdc.com'.

Requirements

• Query User once outside loop. Guard if not found.
• Only assign when Industry = 'Education'.

Problem Statement

Write an Apex trigger CascadeAssistantPhone on the Contact that fires after update.

When AssistantPhone changes and is not null, sync it to the related Account's Phone and all related Opportunities' Phone__c.

Requirements

• Only sync when AssistantPhone actually changes.
• One SOQL with Account + Opportunities subquery. Bulk-safe.

Problem Statement

Write a before insert, before update trigger on the standard object Account that automatically sets a custom field Rating__c to "Hot" whenever AnnualRevenue exceeds 1,000,000.

Best Practices

• Separate trigger logic into a handler class (AccountTriggerHandler).
• Field-only logic belongs in before context — no DML/SOQL needed.
• Bulkify: handle up to 200 records in one trigger invocation.

Objects / Fields

• Account — AnnualRevenue (standard Currency), Rating__c (custom Picklist: Hot/Warm/Cold)

Problem Statement

Write a before update trigger on the standard object Opportunity that blocks the StageName from being changed to "Closed Won" if Amount is null or 0.

Add a field error on Amount using addError().

Best Practices

• Only trigger the check on an actual transition into Closed Won (compare against Trigger.oldMap).
• Handler class pattern, bulk-safe for up to 200 records.

Objects / Fields

• Opportunity — StageName, Amount (both standard)

Problem Statement

Write a before insert trigger on the standard object Lead that checks for duplicate leads based on Email and blocks insertion if a Lead with that email already exists.

Best Practices

• Collect all incoming emails into a Set<String> — one SOQL query total.
• Never query per record inside a loop.

Objects / Fields

• Lead — Email (standard)

Problem Statement

Write a before insert trigger on the custom object Invoice__c that auto-generates a unique Invoice_Number__c using the pattern INV-00001, INV-00002, etc.

Best Practices

• Use one aggregate SOQL (MAX(...)) to find the last used sequence — no per-record query.
• Pad the number using String.leftPad().
• Production caveat: this pattern has a race condition under concurrent inserts. A native Auto Number field type is safer at scale — this exercise is for learning the aggregate-query + padding technique.

Objects / Fields

• Invoice__c — Invoice_Sequence__c (Number), Invoice_Number__c (Text)

Problem Statement

Write a before update trigger on the custom object Employee__c that validates Manager__c is not self-referencing — an employee cannot be their own manager.

Best Practices

• Only relevant on before update — on insert, the record has no Id yet, so self-reference is impossible at that point.
• Pure in-memory check — no SOQL required.

Objects / Fields

• Employee__c — Manager__c (self-lookup to Employee__c)

Problem Statement

Write a trigger CreateCaseOnVipDowngrade on Account that fires after update.

Whenever an Account's Customer_Tier__c changes from 'VIP' to 'Standard', automatically insert a follow-up Case for that Account.

Requirements

• Only create a Case when the tier actually transitions VIP → Standard.
• Collect all Cases into a list and insert once, outside any loop.

Problem Statement

Write a trigger PreventContactWithoutMobileForPremium on Contact that fires before insert.

If a new Contact's parent Account has Customer_Tier__c = 'Premium' and the Contact's MobilePhone is blank, block the insert with addError().

Requirements

• Use a single bulk SOQL query against Account, outside any loop.
• Bulk-safe: handle multiple Contact inserts in one transaction.

Problem Statement

Write a trigger CreateTaskOnContractActivation on Contract that fires after update.

When a Contract's Status transitions to 'Activated', automatically create a follow-up Task assigned to the Contract's OwnerId for renewal planning.

Requirements

• Only fire when the status actually becomes Activated (not if it was already Activated).
• Collect Tasks into a list and insert once, outside any loop.

Problem Statement

Write a trigger PreventCaseReopenAfterFinalClosure on Case that fires before update.

If a Case was Closed with its Final_Closure__c checkbox selected, block any attempt to change its Status away from 'Closed'.

Requirements

• Only block when the Case was actually Closed AND flagged as a final closure.
• Editing other fields on a finally-closed Case (without reopening it) must still work.

Business Scenario

Support wants to proactively fast-track large customers. Whenever an Account is saved, set its checkbox VIP_Support__c to true if both AnnualRevenue >= 5,000,000 and NumberOfEmployees >= 250 — otherwise false.

Requirements

• Runs on both insert and update, before save (no DML needed for the current record).
• Both thresholds must hold — a huge company with no revenue on file, or a small high-revenue company, should not qualify.
• Null AnnualRevenue/NumberOfEmployees must never qualify.

Business Scenario

Sales reps enter Contact phone numbers in inconsistent formats (1234567890, 123-456-7890, (123) 456 7890...). Standardize every 10-digit US phone number to (XXX) XXX-XXXX on save.

Requirements

• Strip all non-digit characters first, then reformat.
• Only reformat when there are exactly 10 digits — leave anything else (international numbers, extensions, partial numbers) untouched.
• Skip blank Phone values entirely.

Business Scenario

Cases created through the company's public web form arrive with SuppliedEmail populated (a self-service field) but sometimes no Origin set. Default Origin to "Web" whenever a new Case has a SuppliedEmail but no Origin yet.

Requirements

• Only applies on creation — never override an Origin an agent later changes.
• Never override an Origin the web form (or an integration) already set.
• Only defaults when SuppliedEmail is present — internally-created Cases with no SuppliedEmail are unaffected.

Business Scenario

Data quality wants every Account's Industry field backfilled automatically the first time an Opportunity is created for it, inferring the industry from the Opportunity's LeadSource (e.g. a simple lookup table). Accounts that already have an Industry must be left alone.

Requirements

• After insert trigger on Opportunity.
• Only update Accounts whose Industry is currently blank.
• If multiple new Opportunities in the same batch reference the same Account, only one update per Account should be attempted.

Best Practices

• Query Accounts once with WHERE Industry = null so the trigger never touches an Account that already has a value — no redundant/overwriting updates.
• Bulkify with Sets and Maps: one SOQL query and one DML statement regardless of how many Opportunities/Accounts are in the batch.
• Wrap the update in try/catch(DmlException).

Business Scenario

Sales wants every new Lead to automatically get a follow-up Task assigned to its owner, due the next day, so no new Lead is ever missed.

Requirements

• After insert trigger on Lead.
• Create one Task per Lead: subject referencing the Lead's name, related to the Lead via WhoId, owned by the Lead's owner, due tomorrow.
• Must handle a bulk insert of up to 200 Leads in one operation.

Best Practices

• Build the full list of Tasks in memory first, then insert once — never insert inside the loop.
• Wrap the DML in try/catch(DmlException) so one problematic Task (e.g. an owner without task-creation permission) doesn't throw an unhandled exception that blocks the whole trigger.

Business Scenario

Account Management wants a custom field Last_Purchase_Date__c (Date) on Account automatically updated whenever one of its Opportunities transitions into Closed Won, reflecting the most recent purchase date.

Requirements

• After update trigger on Opportunity.
• Only act on a real transition into Closed Won (was not already Closed Won).
• If several Opportunities for the same Account close in the same transaction, use the latest CloseDate among them.

Best Practices

• Detect the transition using an index loop over Trigger.new/Trigger.old rather than Trigger.oldMap, since both lists are already index-aligned in an update context.
• Aggregate the latest CloseDate per Account in a Map before any DML — one bulk update regardless of how many Opportunities closed.
• Guard the update with a not-empty check and wrap it in try/catch(DmlException).