Q. What is the difference between trigger and validation rule?
Ans:
validation rules: Validation rules are used to confirm that the data entered into a record meet various data quality / business rules before letting the user save it.
Triggers: Triggers are pure custom coding(Apex) to create solutions for different business problems.it can be used for various different things and can be executed at different times.
Simply i can say validation rule is just blocking invalid data based on business rule, a trigger can do the same thing, but can do more.
