trigger

trigger

(1) 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.

(2) 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.

(3) 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.

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trigger

Machinery a device that releases a spring-loaded mechanism or a similar arrangement

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Trigger

Roy Roger’s horse. [TV: “The Roy Rogers Show” in Terrace, II, 260]

See : Horse

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(database)

trigger - An action causing the automatic invocation of a procedure, for instance to preserve referential integrity. A triggers goes into effect when a user attempts to modify data with an insert, delete, or update command. A trigger can instruct the system to take any number of actions when a specified change is attempted. By preventing incorrect, unauthorized, or inconsistent changes to data, triggers help maintain the integrity of the database. [Sybase SQL Server Release 10.0 Transact-SQL User's Guide].