In this chapter, we covered the topic of triggers and rules. We explored rules and triggers using some identical examples. We established that rules are simple event handlers and triggers are complex event handlers.
We introduced the concept of trigger variables:
- NEW
- OLD
- TG_OP
As well as data-manipulation-based triggers, we briefly introduced the PostgreSQL event triggers that allow developers and database administrators to have more control over firing and executing functions.
We have come to understand that triggers are extremely complex event handlers. In this chapter, we started to show the power of these tools made available to the PostgreSQL DBA; in the next chapter, we will talk about partitioning and we will utilize the topics covered in this chapter.
In the next chapter, we will return to talking about triggers and we will use triggers to create a certain type of partitioning present in PostgreSQL.