normally Salesforce Triggers are simllary to database triggers, they run when you do a dml operation on a object nonally triggers are used to
do complex validations that validation rules doesnt support
execute logics such as field updates , inserting/updating other object recirds , processes etc that should always execute inrrespective of from where dml operations is tirggered (when data is entered via interface as well as back end operations such as dataloading)
nonally triggers are used to