---
title: "Triggers"
id: triggers
pg_version: "20devel"
---

<a id="triggers"></a>

# Triggers

## Table of Contents

- [37.1. Overview of Trigger Behavior](trigger-definition.md)
- [37.2. Visibility of Data Changes](trigger-datachanges.md)
- [37.3. Writing Trigger Functions in C](trigger-interface.md)
- [37.4. A Complete Trigger Example](trigger-example.md)

This chapter provides general information about writing trigger functions. Trigger functions can be written in most of the available procedural languages, including PL/pgSQL ([Chapter 41](plpgsql.md)), PL/Tcl ([Chapter 42](pltcl.md)), PL/Perl ([Chapter 43](plperl.md)), and PL/Python ([Chapter 44](plpython.md)). After reading this chapter, you should consult the chapter for your favorite procedural language to find out the language-specific details of writing a trigger in it. 

It is also possible to write a trigger function in C, although most people find it easier to use one of the procedural languages. It is not currently possible to write a trigger function in the plain SQL function language.