Create a related Contact when an Account is created triggers in Salesforce

 Here's an Apex Trigger that creates a related Contact automatically whenever an Account is created.

trigger CreateContactOnAccountInsert on Account (after insert) {

    List<Contact> contactsToInsert = new List<Contact>();

    for (Account acc : Trigger.new) {

        // Create a Contact for each new Account

        Contact con = new Contact();

        con.FirstName = 'Default';

        con.LastName = acc.Name; // Use Account Name as LastName

        con.AccountId = acc.Id;

        contactsToInsert.add(con);

    }

    // Perform bulk insert of Contacts

    if (!contactsToInsert.isEmpty()) {

        insert contactsToInsert;

    }

}

Explanation of the Code

1. Trigger Event:

   • Runs on the after insert event since the Account ID is needed to associate the Contact with its parent Account.

2. Logic:

   • Loops through all the newly created Account records in Trigger.new.
   • Creates a Contact record for each Account with:
     • A default FirstName (Default in this case).
     • The Account Name as the LastName.
     • Links the Contact to the Account using the AccountId field.

3. Bulk Processing:

• Collects all Contact records in a list and performs a single bulk insert, which is more efficient and avoids governor limits.

@isTest

private class CreateContactOnAccountInsertTest {

    @isTest

    static void testCreateContactOnAccountInsert() {

        // Create a list of Accounts for bulk testing

        List<Account> accounts = new List<Account>{

            new Account(Name = 'Account 1'),

            new Account(Name = 'Account 2'),

            new Account(Name = 'Account 3')

        };

        // Insert the Accounts

        insert accounts;

        // Verify that Contacts are created

        List<Contact> createdContacts = [SELECT FirstName, LastName, AccountId FROM Contact WHERE AccountId IN :accounts];

        System.assertEquals(3, createdContacts.size(), 'Three Contacts should be created for three Accounts');

        // Verify Contact details for the first Account

        Contact contact1 = [SELECT FirstName, LastName FROM Contact WHERE AccountId = :accounts[0].Id];

        System.assertEquals('Default', contact1.FirstName, 'Contact FirstName should be Default');

        System.assertEquals('Account 1', contact1.LastName, 'Contact LastName should match Account Name');

    }

}