(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.
If hackers get their hands on your company's data, they can wreak havoc on customer relationships and cause tremendous damage to your brand and... Read More »Windows XP: Move Along, There's Nothing to See Here
After more than 12 years of holding the title of most popular operating system in the world, Windows XP is taking center stage for its final... Read More »Report: The Role of Big Data in the Marketing Industry
According to a new study from Infogroup Targeting Solutions, we can expect to see companies spend heavily on big data marketing initiatives in... Read More »
Creating desktop shortcuts to a websites is useful. When you double-click the icon from your desktop it automatically launches the browser and... Read More »Flash Data Storage Vendor Trends
Although it is almost impossible to keep up with the pace of ongoing product releases, here are three recent highlights in the flash data storage... Read More »15 Important Big Data Facts for IT Professionals
Keeping track of big data trends, research and statistics gives IT professionals a solid foundation to plan big data projects. Here are 15... Read More »
Stay up to date on the latest developments in Internet terminology with a free weekly newsletter from Webopedia. Join to subscribe now.
- Check out eWeek's new Research Center, a central and comprehensive library of whitepapers, eBooks, eseminars, webcasts, and more from top industry brands and independent tech journalists »
- Watch Datamation's editor James Maguire moderate roundtable discussions with tech experts from companies such as Accenture, Dell, Blue Jeans Network, Microsoft and more »