Setting a field value to the same object with a Trigger

Question

I have two fields.

Cost_price__c & Previous_book_value__c

Currently, I use a Trigger on my Asset object to create a bunch of other objects and related records. However, I need to map the field of Previous_book_value__c to the same as Cost_price__c to work with them both.

I can't use the Previous_book_value__c as a formula field, I need them both to remain as a Currency field.

My plan is to add a second Trigger Context variable to deal with the field before inserting as inserting afterwards won't work. I feel like it's simple and I'm over complicating the entire process.

Could I get some indication on where to get started please?

Many thanks

Code:

trigger CreateProjectfromAsset on Asset (before insert, after insert, after update) {

if(Trigger.isInsert){
    if(Trigger.isAfter){
        AssetCreationController.assetCreation(Trigger.new);
    }
    if(Trigger.isBefore){
      System.debug('Need to set the field value of Previous_book_value__c to be the same as Cost_price__c');
    }

    }

}

if(Trigger.isUpdate ){
    AssetCreationController.assetUpdate(Trigger.new);
}

}

Answer 1

Just put this logic in a Workflow Rule Field Update. Using an Apex Trigger for this functionality is overkill, and it's usually better to use declarative functionality over code where it will work.