Types of Triggers in PL/SQL and Their Usage

Triggers in PL/SQL are event-driven pieces of code that are executed in response to certain actions or events performed on a database table. There are several types of triggers in PL/SQL, each serving a specific purpose:

1. Row Trigger: Row triggers fire for each row affected by the triggering statement. They are commonly used to enforce complex business rules or data integrity constraints.
2. Statement Trigger: Statement triggers fire once for each triggering SQL statement, regardless of the number of rows affected. They are often used for auditing or logging purposes.
3. Before Trigger: Before triggers execute before the triggering statement is performed, allowing you to validate or modify the data before it is actually changed in the table.
4. After Trigger: After triggers execute after the triggering statement has been performed, useful for implementing complex post-processing logic.
5. Instead of Trigger: Instead of triggers are used on views and allow you to override the default DML behavior, enabling you to perform custom actions when data manipulation operations are attempted on the view.

Each type of trigger has its own specific use case and can be utilized to enforce data integrity, enhance performance, or implement custom business logic within your PL/SQL code.