Hi,

Forgive me if this seems like a silly question. However, I have been googling for some time on this subject.

I was wondering about the best way to add additional form validation and error message handling. For example, if I have a column that is a number, what is the best way to present a pretty error message if the user enters characters?

I looked into custom validation through the ConstraintValidator interface. For this kind of validation, this does not appear to be the correct methodology.

I am looking to do add pretty user error messages if:
  • Entry in form should be a number and user enters characters
  • Unique constraint violations
  • Database issues such as connection errors
  • User tries to delete a child that has a parent assigned


What is the best methology for adding these kinds of validations?