2026-06-09 –, Palais Atelier
This talk explains how constraints work in Postgres by exploring the pg_constraint catalog and core concepts like table vs. column constraints, constraint triggers, domains and constraint deferrability through SQL queries. It then covers what’s new in Postgres 18 including temporal keys, NOT NULL as a first-class constraint, NOT ENFORCED and more.
PostgreSQL 18 introduces significant enhancements to constraints, the first line of defense for maintaining data integrity. This talk focuses on new capabilities in version 18, including non-overlapping PRIMARY KEY, UNIQUE, and foreign key constraints; NOT NULL constraints becoming first-class citizens; the introduction of NOT ENFORCED constraints and improved support for partitioned tables. We’ll look at what’s new, why it matters and how to apply these features in real-world systems.
We’ll begin with a detailed walkthrough of the pg_constraint catalog, covering less commonly discussed concepts such as constraint deferrability, constraint triggers, domains and related internals. From there, we’ll move on to what’s new in PostgreSQL 18. A major addition is temporal keys, bringing PostgreSQL a step closer to supporting temporal data models. Another key change is NOT NULL becoming a standard constraint along with the implications of that promotion. We’ll also explore NOT ENFORCED constraints and other recent additions and briefly look ahead to what’s coming in PostgreSQL 19.
Gülçin started working with PostgreSQL at a startup in 2012 and was immediately struck by how powerful it is. Since then, she has been an active member of the PostgreSQL community, organizing conferences, giving talks and contributing in various ways. In recognition of her commitment, she was elected to the PostgreSQL Europe Board in 2017 and recognized as a PostgreSQL contributor in 2024.
Driven by her interest in PostgreSQL automation and cloud technologies, Gülçin joined 2ndQuadrant where she led cloud development efforts until the company was acquired by EDB in 2020. She is also an active member of Postgres Women, advocating for greater diversity and inclusion in technical communities.
Gülçin currently works at Xata, where she continues to focus on PostgreSQL engineering. Beyond her professional work, she is a co-founder of Kadin Yazilimci (Women Developers of Turkey) and has led its core team for more than 11 years. In 2023, she launched the Diva: Dive into AI conference as a Kadin Yazilimci initiative and has been part of the organizing team since.
She lives in Prague where she is the co-founder and organizer of the monthly Prague PostgreSQL Meetup for over eight years. Gülçin remains deeply involved in the PostgreSQL community and is committed to contributing to the long-term health and sustainability of the project.