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Saumya SumanSaumya Suman 

When we use before update event in trigger?

Meenu MathewMeenu Mathew
Hi Saumya,

We use before triggers to validate data or update fields on the same record being triggered.
We use update for events on existing records.

Before Update
  • It’s going to store the set record before update to database.
  • In Before Update we can change fields using trigger.new.
  • Updating of original object using an update DML operation is not allowed. A runtime error is thrown.
  • Deleting of original object using a delete DML operation is also not allowed. Runtime error will be thrown
Eg. for Before Update on Contact: 
list<account> acclist = new list<account>();
    for(contact acc:trigger.old){
        account c = new account();
        c.Name=acc.lastname;
        c.Phone=acc.phone;
        acclist.add(c);
    }
insert acclist;

You can refer the following links
https://www.janbasktraining.com/blog/what-is-trigger-in-salesforce/
http://www.sfdc99.com/2014/01/25/use-vs-triggers/

Thanks
Eden WheelerEden Wheeler
Hi ,
The "before update" event in a trigger is used to execute certain actions or modifications to data before a record is updated in the database.

A "before update" trigger is fired when a record is updated and allows you to access and modify the record's fields before the update is saved to the database. This trigger can be used to perform various operations like validation checks, calculations, and field updates.

For example, if you have a custom object called "Opportunity" and you want to update a field called "Amount" based on the value of another field called "Quantity," you can use a "before update" trigger to perform this calculation automatically when the "Quantity" field is updated.

Another use case for a "before update" trigger is data validation. For instance, you can ensure that certain fields are not left blank, or that a certain field value meets certain criteria before allowing the update to proceed.

In summary, the "before update" trigger event is used to execute certain actions or modifications before a record is updated to the database.

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