Bonus cards, “Miles & more”, bonus points – don’t we all love and hate them at the same time? Recently we had an interesting use case which made me think about sharing some of the techniques we used in this area to reduce client code by writing some clever SQL. This post will show you […]

  © Renée Albe 2022 Case-insensitive search is a much-requested feature, partly (I suspect) to maintain compatibility with Microsoft SQL Server. There are several solutions to the problem, one of which is to use case-insensitive ICU collations. This works like a charm, except if you want to perform pattern matching. So let’s have a closer […]

© Laurenz Albe 2022 Next to character encoding, time zones are among the least-loved topics in computing. In addition, PostgreSQL’s implementation of timestamp with time zone is somewhat surprising. So I thought it might be worth to write up an introduction to time zone management and recommendations for its practical use. Time zones and the […]

Normalization by Osmosis Part 2: Practical Examples of Data Normalization in PostgreSQL Having gone through a theoretical introduction in part 1, it is now time to discuss some more practical examples. I’ll first talk about the… type modeling … of columns. It is important to realize that during the time Codd formulated the base 3 […]

Normalization by Osmosis Part 1: A Guide to Data Normalization in PostgreSQL  By Michał Małecki Introduction Although I installed my first PostgreSQL database on RedHat Linux (not RHEL) 6.0 around 1999, I probably limited my interaction with this 6.5 release to starting the server with SysinitV scripts. PostgreSQL was at that time an underdog to […]

PostgreSQL table partitioning is by far one of the most popular new PostgreSQL features. Many people look to partitioned tables as a way to improve performance and broaden scalability. However, partitioning comes with a little problem: How can you partition an existing table without locking up the database? The answer is: pg_rewrite can help you […]

Most of my readers will know about primary keys and all kinds of table constraints. However, only a few of you may have ever thought about the difference between a primary key and a UNIQUE constraint. Isn’t it all just the same? In both cases, PostgreSQL will create an index that avoids duplicate entries. So […]

© Laurenz Albe 2021 Both cursors and transactions are basic ingredients for developing a database application. This article describes how cursors and transactions interact and how WITH HOLD can work around their limitations. We will also see the dangers involved and how to properly use WITH HOLD cursors in a PL/pgSQL procedure. Cursors in PostgreSQL […]

In this article, I will answer the questions: why isn’t there a  SHOW TABLES command in PostgreSQL, when will SHOW TABLES in PostgreSQL be available, and how do I list tables with native PostgreSQL methods? Why isn’t there a SHOW TABLES command in PostgreSQL? People who come from MySQL are always asking the same question: […]

Most people in the SQL and in the PostgreSQL community have used the LIMIT clause provided by many database engines. However, what many do not know is that LIMIT / OFFSET are off standard and are thus not portable. The proper way to handle LIMIT is basically to use SELECT … FETCH FIRST ROWS. However, […]

© Laurenz Albe 2021 EXPLAIN ANALYZE is the key to optimizing SQL statements in PostgreSQL. This article does not attempt to explain everything there is to it. Rather, I want to give you a brief introduction, explain what to look for and show you some helpful tools to visualize the output. How to call EXPLAIN […]

© Laurenz Albe 2021 UPDATED 14.05.2022: Sometimes customers ask me about the best choice for auto-generated primary keys. In this article, I’ll explore the options and give recommendations. Why auto-generated primary keys? Every table needs a primary key. In a relational database, it is important to be able to identify an individual table row. If […]