APEX TRAINING -4:

This trigger uses boolean context variables
trigger myAccountTrigger on Account(before delete, before insert, before update,
after delete, after insert, after update) {
if (Trigger.isBefore) {
if (Trigger.isDelete) {
// In a before delete trigger, the trigger accesses the records that will be
// deleted with the Trigger.old list.
for (Account a : Trigger.old) {
if (a.name != 'okToDelete') {
a.addError('You can\'t delete this record!');
}
}
} else {
// In before insert or before update triggers, the trigger accesses the new records
// with the Trigger.new list.
for (Account a : Trigger.new) {
if (a.name == 'bad') {
a.name.addError('Bad name');
}
}
if (Trigger.isInsert) {
for (Account a : Trigger.new) {
System.assertEquals('xxx', a.accountNumber);
System.assertEquals('industry', a.industry);
System.assertEquals(100, a.numberofemployees);
System.assertEquals(100.0, a.annualrevenue);
a.accountNumber = 'yyy';
}
// If the trigger is not a before trigger, it must be an after trigger.
} else {
if (Trigger.isInsert) {
List<Contact> contacts = new List<Contact>();
for (Account a : Trigger.new) {
if(a.Name == 'makeContact') {
contacts.add(new Contact (LastName = a.Name,
AccountId = a.Id));
}
}
insert contacts;
}
}
}}}