Rule: AvoidLogicInTrigger

Message

Avoid logic in triggers

Description

As triggers do not allow methods like regular classes they are less flexible and suited to apply good encapsulation style. Therefore delegate the triggers work to a regular class (often called Trigger handler class).

See more here: https://developer.salesforce.com/page/Trigger_Frameworks_and_Apex_Trigger_Best_Practices

Priority

3

Example

trigger Accounts on Account (before insert, before update, before delete, after insert, after update, after delete, after undelete) {
    for(Account acc : Trigger.new) {
        if(Trigger.isInsert) {
            // ...
        }

        // ...

        if(Trigger.isDelete) {
            // ...
        }
    }
}