(90 minute tutorial) Writing a PostgreSQL procedural language is an effective way to get used to the PostgreSQL source code and how to function within it, and provides some interesting insights into things like interpreter/compiler development, PostgreSQL's context-based memory model, and SPI. This tutorial will cover how to use Flex and Bison, the tokenizer and parser systems at the heart of PL/LOLCODE (as well as PL/pgSQL, the PostgreSQL query parser, and several contrib modules), the Server Programming Interface, how Datums move around inside PostgreSQL, and how language handlers work.