A database trigger is a type of stored code that executes automatically in response to specific events on a specific table or view in a database. Triggers are used to ensure the accuracy and integrity of information in a database, such as creating new records in tables for taxes, vacations, and salaries when a new employee record is added. They can also be used to record historical data. Triggers can be designed to execute before, during, or after data manipulation operations like INSERT, UPDATE, and DELETE, and help ensure specific tasks, such as keeping an audit file, are carried out.
FAQs about Database Triggers
What is a database trigger?
A database trigger is a piece of procedural code that executes automatically in response to specific events on a specific table or view. It serves to ensure data accuracy in the database and can also be used to record historical data.
What events trigger a database trigger?
A database trigger is typically programmed to execute whenever there is a change to a table’s data. This can happen before, during, or after DML operations such as INSERT, UPDATE, and DELETE.
How does a database trigger help with database design?
Database triggers help the database designer ensure specific tasks are carried out, such as keeping an audit file. They are also used to make sure linked actions are performed in a coordinated manner.
What databases support triggers?
Triggers are supported by all major relational databases, although there may be implementation variations.
What are some practical examples of database triggers?
One example of a database trigger is sending a notification email to an employee’s manager after they submit a leave request. Another example is creating new records in tables for taxes, vacations, and salaries whenever a new employee is added to the employees table.
In In conclusion, a database trigger is an important tool for ensuring data accuracy and coordinating linked actions in a database. It is supported by all major relational databases and can be programmed to execute in response to specific events such as DML operations. Practical examples of database triggers include sending notifications and creating new records in related tables.