Book Image

Learn PostgreSQL

By : Luca Ferrari, Enrico Pirozzi
Book Image

Learn PostgreSQL

By: Luca Ferrari, Enrico Pirozzi

Overview of this book

PostgreSQL is one of the fastest-growing open source object-relational database management systems (DBMS) in the world. As well as being easy to use, it’s scalable and highly efficient. In this book, you’ll explore PostgreSQL 12 and 13 and learn how to build database solutions using it. Complete with hands-on tutorials, this guide will teach you how to achieve the right database design required for a reliable environment. You'll learn how to install and configure a PostgreSQL server and even manage users and connections. The book then progresses to key concepts of relational databases, before taking you through the Data Definition Language (DDL) and commonly used DDL commands. To build on your skills, you’ll understand how to interact with the live cluster, create database objects, and use tools to connect to the live cluster. You’ll then get to grips with creating tables, building indexes, and designing your database schema. Later, you'll explore the Data Manipulation Language (DML) and server-side programming capabilities of PostgreSQL using PL/pgSQL, before learning how to monitor, test, and troubleshoot your database application to ensure high-performance and reliability. By the end of this book, you'll be well-versed with the Postgres database and be able to set up your own PostgreSQL instance and use it to build robust solutions.
Table of Contents (27 chapters)
Section 1: Getting Started
Section 2: Interacting with the Database
Section 3: Administering the Cluster
Section 4: Replication
Section 5: The PostegreSQL Ecosystem


In this section, we will look at some interesting features of the insert statement:

  • How to make an upsert statement starting from an insert statement
  • How to make a SQL query that inserts the same data and returns the record inserted

UPSERT – the PostgreSQL way

In PostgreSQL, the upsert statement does not exist as in other DBMSes. An upsert statement is used when we want to insert a new record on top of the existing record or update an existing record. To do this in PostgreSQL, we can use the ON CONFLICT keyword:

INSERT INTO table_name(column_list) VALUES(value_list)
ON CONFLICT target action;

Here, ON CONFLICT means that the target action is executed when the record already exists (meaning when a record with the same primary key exists). The target action could be this:


Alternatively, it could be the following:

 DO UPDATE SET { column_name = { expression | DEFAULT } |
( column_name [, ...] ) = [ ROW ] ( { expression | DEFAULT } [, ...] ) |
( column_name...