Triggers allow applications to monitor and respond to database events. They execute automatically in response to data manipulation language (DML) statements like insert, update, delete or database definition language (DDL) statements like create, alter, drop. Triggers enforce business rules, data integrity, auditing and more. They are defined on tables, views, schemas or databases and specify when they are executed based on events and optional conditions. Triggers can update or insert data, prevent invalid transactions and maintain referential integrity across distributed databases.