A mechanism that initiates an action when an event occurs such as reaching a certain time or date or upon receiving some type of input. A trigger generally causes a program routine to be executed.
In a database management system (DBMS), a trigger is an SQL procedure that is executed when a record is added or deleted. It is used to maintain referential integrity in the database. A trigger may also execute a stored procedure. Triggers and stored procedures are built into DBMSs used in client/server environments. See intelligent database
A condition that initiates the harmful effects of a logic bomb such as many viruses and worms. Many forms of malicious software use particular dates as triggers. Some viruses count the number of infections and trigger their payloads at a specific number.