How do you write Apex triggers?

How do you write Apex triggers?

Get Started with Apex Triggers

1. Write a trigger for a Salesforce object.
2. Use trigger context variables.
3. Call a class method from a trigger.
4. Use the sObject addError() method in a trigger to restrict save operations.

What are Apex triggers?

Apex triggers enable you to perform custom actions before or after events to records in Salesforce, such as insertions, updates, or deletions. Triggers can be defined for top-level standard objects, such as Account or Contact, custom objects, and some standard child objects. Triggers are active by default when created.

What is Undelete trigger?

The after undelete trigger event only works with recovered records—that is, records that were deleted and then recovered from the Recycle Bin through the undelete DML statement. The after undelete trigger events only run on top-level objects. For example, if you delete an Account, an Opportunity may also be deleted.

How to write undelete triggers in Salesforce Stack Exchange?

AccountUndelete: execution of AfterUndelete caused by: System.FinalException: Record is read-only Trigger.AccountUndelete: line 5, column 1 You need to explicitly query Account record to update it.

What does trigger in before or after delete mean?

Trigger.old in Before or After delete : This will store the list of records which are already present in your database. Meaning that you are performing the delete operation on existing records in Salesforce. This will store the list of records which we are trying to delete.

How to delete Contact Records in apex trigger?

Whenever we try to update the phone of account record then update the related contact phone no. with the new account phone no. before account record is updated. When we delete the account record then delete the corresponding Contact records.

How does create trigger for update work in SQL Server?

For example, if CREATE TRIGGER FOR UPDATE is run for a table that already has an UPDATE trigger, an additional update trigger is created. In earlier versions of SQL Server, only one trigger for each INSERT, UPDATE, or DELETE data modification event is allowed for each table.