Chapter 34. Triggers
This chapter provides general information about writing trigger functions.
Trigger functions can be written in most of the available procedural
PL/pgSQL (Chapter 37),
PL/Tcl (Chapter 38),
PL/Perl (Chapter 39), and
PL/Python (Chapter 40).
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.