Triggers – 2 marks in Database Management Systems
Anna University third semester
1. What is trigger?
A trigger is a statement that system automatically executes as a result of side effect of modification to the database.
2. What are two requirements to be met to design a trigger mechanism?
1. specify when a trigger is to be executed
2. Specify what actions to be taken when trigger executes
This is called event-condition-action model for triggers
3. Who is responsible for executing triggers?
Database systems
4. What is the need for triggers?
Triggers are useful mechanisms for altering humans for starting out certain tasks automatically when certain conditions are met.
5. Applications where the triggers are used
1. Triggers are used for replication of the database
2. System designers use it for maintaining summary data
6. What is the future of triggers?
Triggers are replaced by stored procedures for security reasons
Note: triggers are otherwise called as rules
7. What is an audit-trial in database
An audit trial is a log of all changes that are performed to the database along with information such as which user performed the change and when did they perform the modification to the database.
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