Trigger

(n.) In a DBMS, a trigger is a SQL procedure that initiates an action (i.e., fires an action) when an event (INSERT, DELETE or UPDATE) occurs. Since triggers are event-driven specialized procedures, they are stored in and managed by the DBMS. A trigger cannot be called or executed; the DBMS automatically fires the trigger as a result of a data modification to the associated table. Triggers are used to maintain the referential integrity of data by changing the data in a systematic fashion.

Each trigger is attached to a single, specified table in the database.

Triggers can be viewed as similar to stored procedures in that both consist of procedural logic that is stored at the database level. Stored procedures, however, are not event-drive and are not attached to a specific table as triggers are. Stored procedures are explicitly executed by invoking a CALL to the procedure while triggers are implicitly executed. In addition, triggers can also execute stored procedures.

A trigger can also contain INSERT, UPDATE and DELETE logic within itself, so when the trigger is fired because of data modification it can also cause another data modification, thereby firing another trigger. A trigger that contains data modification logic within itself is called a nested trigger.

(v.) To initiate an action.

Vangie Beal
Vangie Beal
Vangie Beal is a freelance business and technology writer covering Internet technologies and online business since the late '90s.

Related Articles

10 Quick Tips For Social Media Marketing

10 Quick Tips for Social Media Marketing Social Media Defined: Social media is a phrase used to describe a variety of Web-based platforms, applications and...

Digital Advertising

What is Digital Advertising? Digital advertising is marketing to a target audience through digital platforms, including social media, email, search engines, mobile apps, affiliate programs,...

E-Commerce

E-commerce, or electronic commerce, is online-conducted business, including marketing, sales, and fulfillment. Consumers and businesses place and track orders at least partially through the...

Virtualization Software

Virtualization software is a digital solution used to create an abstraction layer for hardware. The software creates multiple instances, or virtual machines (VMs), that...

ScalaHosting

ScalaHosting is a leading managed hosting provider that offers secure, scalable, and affordable...

HRIS

Human resources information system (HRIS) solutions help businesses manage multiple facets of their...

Best Managed Service Providers...

In today's business world, managed services are more critical than ever. They can...