Can a trigger on one object update all records?
The records that fire the after trigger are read-only. A trigger on one object cannot update values of any related record (child or parent) without using DML. There’s simply no way around that 1. If your trigger is on Account, you will need to use DML and have your Contact records fire their own trigger (s).
How to update field values from another object?
Now, if the values match then another field called X in A has to be populated with the value of X which is in object B. I’ve written a trigger for this on Object B but while trying to dataload few records of B i’m getting this error Execution Of AfterUpdate Caused By: System.ListException: Duplicate Id In List.
When to update custom objects in apex trigger?
First, it is normally better to update other objects in an “after” trigger. If this runs in the before insert, the OBJ.ID will be null. Also, the way this is currently written, you will only get the last updated/inserted custom object to work correctly. You’ll need to “bulkify” this to work for the whole list of custom objects.
What is the purpose of the after trigger?
After triggers are used to access field values that are set by the system (such as a record’s Id or LastModifiedDate field), and to affect changes in other records, such as logging into an audit table or firing asynchronous events with a queue. The records that fire the after trigger are read-only.
When to compare Old and new field values in trigger?
For example, we may have requirement that send an email to VP of company or do some task when an opportunity status is changed to Closed Won. So, we have to compare old and new field values in trigger to make it sure.
How to update before trigger in Salesforce developer community?
In the above code you are specificalluy pointing to Contact record with id=0039000000Mehth. When trigger excutes, it will take into the consideration all the records which meet criteria, like here we have Before Update; so any contact record which will get updated will fire the trigger and then the description will be updated.
Can You update the contact record before trigger?
Above code is updating the Contact record in it’s before trigger but the statement in the book says something else. Please explain. It means you can not do any dml like update or delete for the object on which you are writing trigger. Your trigger is updating the contact itself.