![]() ![]() ![]() Quote character varying ( 255 ) NOT NULL UNIQUE ,Īuthor_id INTEGER REFERENCES author (id ) ON DELETE CASCADE , Updated_at timestamp with time zone DEFAULT CURRENT_TIMESTAMP NOT NULL Name character varying ( 255 ) NOT NULL ,Ĭreated_at timestamp with time zone DEFAULT CURRENT_TIMESTAMP NOT NULL , In terms of Postgres Data Definition Language (DDL), the above ER diagram with two related entities translates to the following create table statements: CREATE TABLE author ( It can be represented in an ER diagram as follows (diagram generated with dbdiagram.io): One author can have multiple quotes and one quote will always have only one author. Author and Quotes example #įor this tutorial, you will use an example of an author and quotes. Given that is mentioned, you can continue with the guide now. Being able to read Entity Relationship (ER) diagrams will make it easier for you to understand the context.Previous understanding of how foreign keys work in RDBMS will be advantageous. ![]() Prior experience with any relations database management system (RDBMS) would be helpful.You can use a local Postgres Docker instance or simply use a free database on Elephant SQL or Neon.tech You should have a working Postgres server instance to test your code.In this guide, you will learn how to set up and use ON DELETE CASCADE in foreign keys in Postgres, let’s get going! Table of contents #īefore diving into the SQL code, below are some prerequisites for this tutorial: One of the useful features of PostgreSQL is on delete cascade that simplifies the code in your application. Postgres is one of the most popular open-source relational database systems in use today. ![]()
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