Answer / Harminder Kaur

A trigger in SQL and PL/SQL is a special kind of stored procedure that automatically responds to certain events (such as insert, update, or delete) on a specific table. Triggers are used to enforce business rules, maintain data integrity, and perform auditing functions. An example of a trigger in SQL would be creating an AFTER INSERT trigger on the 'employees' table to automatically assign a unique ID to each newly inserted record:

```sql
CREATE TRIGGER auto_id_insert
AFTER INSERT ON employees
FOR EACH ROW
BEGIN
SET new.id = (SELECT MAX(id) + 1 FROM employees);
END;
```
In this example, the trigger 'auto_id_insert' is created to be activated after an insert operation on the 'employees' table. For each row inserted, the new value of 'id' will be set to the maximum 'id' from the 'employees' table plus one.

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