Mastering PostgreSQL 12 - Third Edition

Writing triggers in Perl

Every stored procedure language that is shipped with the core of PostgreSQL allows you to write triggers in that language. The same, of course, applies to Perl. Since the length of this chapter is limited, I have decided not to include an example of a trigger written in Perl, but instead to point you to the official PostgreSQL documentation: https://www.postgresql.org/docs/10/static/plperl-triggers.html. Basically, writing a trigger in Perl doesn't differ from writing one in PL/pgSQL. All predefined variables are in place, and as far as return values are concerned, the rules apply in every stored procedure language.